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A-type Natriuretic Peptide  (ANP)
22–77 pg/mL; SI units: 22–77 ng/L
. Lavender-top tube. Immediately send to lab on ice. Specimen
may need to be fasting; check with lab.
■ Secreted by atrial myocardium; exerts an antihypertensive
effect by increasing the renal excretion of sodium and water.
■ Secreted from the atria in response to atrial wall stretch.
■ Less useful than B-type natriuretic.
Acid-fast Bacillus Stain (AFB)
Negative for acid-fast organisms
. Sputum specimen sent in a sterile collection cup. Gastric
washings/aspirates, urine, cerebral spinal fluid (CSF), other body
fluids, or tissue samples may also be tested.
■ Sputum samples should be induced in the early morning to
obtain the best specimen.
■ Collect specimens for 3 days.
■ Tests for Mycobacterium tuberculosis, atypical mycobacteria,
or other acid-fast bacteria. See Tuberculosis Culture.
Acid Phosphatase (ACP, Prostatic Acid Phosphatase, PAP)
2.6 ng/mL or 0.5 IU/L; SI units: 2.2 – 10.5 U/L
. Red-top tube.
■ Assess prostate cancer metastasis, treatment effectiveness.
■ Infrequently done; usual test is PSA, prostate-specific antigen.
ACTH (Adrenocorticotropic Hormone)
AM: 80 pg/mL; SI units: 18 pmol/L
PM: 50 pg/mL; SI units: 11 pmol/L
. Green-top tube.
■ Assess signs and symptoms of adrenocortical dysfunction.
■ Sample must be iced and sent to lab immediately.
ACTH Stimulation Test (Cosyntropin Stimulation Test)
7 g/dL over baseline in rapid screening test
40 g/dL over baseline in 1- or 3-day test
. Green-top tube.
■ Differentiate between pituitary-induced adrenal dysfunction
and adrenal insufficiency.
■ Test involves obtaining a baseline ACTH level, administering
cosyntropin (a synthetic ACTH-like drug) over a prescribed
period, and drawing repeat ACTH levels.
Activated  Partial Thromboplastin Time  (aPTT)
See Partial Thromboplastin time (PTT).
Antithrombin III (AT-III)
21–30 mg/dL; SI units: 210–300 mg/L
. Blue- or red-top tube.
■ Assess patients with thromboses.
■ Patients with low levels are resistant to heparin therapy.
Alanine aminotransferase (ALT)
10–35 U/L; SI units: 0–0.58 mkat/L
. Red-top tube.
■ Enzyme found in liver cells.
■ Used in diagnosis of liver, biliary, and pancreatic disease.
Adult: 3.5–5 g/dL; SI units: 35–50 g/L
Child: 3.8–5.4 g/dL; SI units: 38–54 g/L
. Red-top tube.
■ Main plasma protein; helps maintain osmotic pressure.
Decreased albumin causes fluid shifts and resultant edema.
■ Levels decrease in renal or hepatic disease, acute infection,
malnutrition, malignancy, diabetes, and many other chronic
and acute conditions.
Albumin Cobalt Binding Test (ACB Test) (Ischemia-modified
Albumin [IMA])
 85 U/mL
. Red-top tube.
■ A new cardiac marker test. The binding properties of albumin
change when it comes into contact with ischemic heart tissue
(ischemia-modified albumin [IMA]) making it less able to bind
with cobalt. When a cobalt solution is added to the serum,
cobalt binds to the normal albumin but not to IMA. More free,
or unbound, cobalt indicates the presence of abnormal
■ Level rises within a few minutes of the onset of cardiac
ischemia. Allows a greater window of time for therapeutic
intervention as other markers only detect cardiac muscle
necrosis, not ischemia.
■ Used in conjunction with ECG and troponin levels to evaluate
etiology of chest pain.
Albumin/Globulin Ratio (A/G Ratio)
. Calculated from total protein and albumin levels.
■ Total protein – albumin  globulins. Albumin ÷ globulins  A/G
■ Serum protein electrophoresis has replaced the A/G ratio.
Aldosterone, Serum
7–30 ng/dL; SI units: 190–832 pmol/L (drawn in upright position)
3–16 ng/dL; SI units: 80–440 pmol/L (drawn in supine position)
. Red-or green-top tube.
■ Aldosterone is a potent mineralocorticoid that regulates sodium,
potassium, and water balance.
■ Used with plasma rennin levels to distinguish between primary or
secondary (more common) hyperaldosteronism.
Aldosterone, Urine
2–26 g/24 hr; SI units: 6–72 nmol/24 hr
. 24-hr urine collection.
■ Aldosterone is a potent mineralocorticoid that regulates sodium,
potassium, and water balance.
■ Used to diagnose primary or secondary hyperaldosteronism.
Alkaline Phosphatase (ALP)
Adult: 42–136 U/L
Child: 50–230 U/L
. Red-top tube.
■ Enzyme found predominately in the liver, biliary tract, and bone.
■ Useful in assessing liver and bone disease.
■ ALP isoenzymes distinguish between liver and bone disease. ALP1 is
hepatic; ALP2 is from bone.
Alpha-Fetoprotein (AFP, a-Fetoprotein)
Men, Nonpregnant Females: 16 ng/mL; SI Units: 16 mL
Pregnant Females at 15–18 Weeks’ Gestation: 10–150 ng/mL; SI units:
10–150 mL
. Red-top tube.
■ In men and nonpregnant females as a tumor marker to aid in
diagnosis of hepatocellular carcinoma, testicular tumor, ovarian
cancer. May be elevated in alcoholic cirrhosis.
■ In pregnancy to detect fetal neural tube defect, multiple pregnancy,
fetal distress, fetal death.
Adult: 15–45 g/dL; SI units: 11–35 mol/L
Child: 29–70 g/dL; SI units: 29–70 mol/L
. Green-top tube.
■ Ammonia forms when protein is broken down by bacteria in the
intestinal tract. It is then converted to urea by the liver and excreted
by the kidneys.
■ Elevated in liver failure. Elevations manifest as encephalopathy
(lethargy, confusion, tremors, coma).
Amylase, Serum
Adult: 60–160 Somogyi U/dL; SI units: 30–70 U/L
. Red-top tube.
■ Secreted by the pancreas and elevated in pancreatic disorders.
■ Damaged or obstructed pancreatic cells cause amylase to spill into
lymph ducts and the peritoneum where excess amylase is picked up
by by the blood.
Anion Gap (AG)
8–16 mEq/L
. Calculated from electrolyte values.
■ Anion gap equals the difference between the cations (sodium and
potassium) and the anions (chloride and bicarbonate).
■ (Na
) – (Cl-
-)  AG
■ Elevated AG (17 mEq/L) is associated with metabolic acidosis.
■ Decreased AG (8 mEq/L) is associated with metabolic alkalosis
(see ABG section in this Tab).
Antibodies, Auto
◆ Anticentomere antibody
◆ Anti-DNA antibody
◆ Antiglomerular basement membrane antibody
◆ Antimicrosomal antibody
◆ Antimitochondrial antibody
◆ Antimyocardial antibody
◆ Antineutrophil cytoplasmic antibody (ANCA)
◆ Antinuclear antibody (ANA)
◆ Antiparietal cell antibody
◆ Antiscleroderma antibody (SCL 70)
◆ Antismooth muscle antibody
◆ Sjögren syndrome antibody (SS-A)
Negative. Reference ranges and measurement units for
individual tests vary as does the amount of detectable antibody
that constitutes a positive result. Results may be reported as the
amount of antibody detected and if the values are considered
negative, positive, or equivocal.
. Red-top tube.
■ Autoantibodies are proteins created by the immune system
that attack the body’s own tissues or organs.
■ Autoantibodies represent a failure by the immune system
to distinguish between foreign proteins and the body’s own
■ Elevated autoantibody levels are found in people with
autoimmune disorders such systemic lupus erythematosus
■ Autoimmune disorders may be organ specific as in Graves’
disease, or systemic, as in vasculitis.
Antidiuretic Hormone (ADH); ADH Suppression Test
ADH: 1–5 pg/mL; SI units: 1.5 ng/L
ADH suppression test: 80% of waterload excreted in 5 hr; Urine
osmolality ≥100 mmol/kg; Urine to serum osmolality ratio 100;
Urine specific gravity 1.003.
. Red-top tube, plastic.
■ ADH controls the amount of water resorbed by the kidney.
■ Inadequate ADH secretion results in diabetes insipidus (DI).
■ Excess secretion of ADH related to various cancers (lung,
pancreas, urinary tract, blood) results in syndrome of
inappropriate ADH (SIADH).
Antistreptolysin O/Antistreptococcal O Titer (ASO)
Adult and preschool age child: 100 IU/mL
Child (school age) : 200 IU/mL
. Red-top tube
■ Streptolysin is an enzyme secreted by beta-hemolytic strep-tococci. It causes an antibody response that begins to rise 1
week after streptococcal infection and peaks in 2–3 weeks.
■ High serum ASO levels are seen with acute rheumatic fever,
poststreptococcal glomerulonephritis, and collagen
Coventional SI Units
Apo A-I
◆ Male
◆ Female
Apo B
◆ Male
◆ Female
Lipoprotein (a)
◆ Caucasians
• Male
• Female
◆ African-Americans
• Male
• Female
. Red-top tube.
■ Proteins that transport cholesterol in the bloodstream.
■ Used to evaluate the risk of corobary artery disease.
■ Ratio of Apo-I to Apo B is calculated to further stratify risk.
81–166 mg/dL
80–214 mg/dL
46–174 mg/dL
46–146 mg/dL
2.2–49.4 mg/dL
2.1–57.3 mg/dL
4.6–71.8 mg/dL
4.4–75 mg/dL
0.81–1.66 g/L
0.8–2.14 g/L
0.46–1.74 g/L
0.46–1.46 g/L
0.02–0.49 g/L
0.02–0.57 g/L
0.05–0.72 g/L
0.04–0.75 g/L
7 Arterial Blood Gases (ABGs)
Normal ABG Results (US System of Measurements)
pH PaO2 PaCO2 O2 Saturation HCO3 Base Excess
7.35–7.45 80–100 mm Hg 35–45 mm Hg 95–100% 21–28 mEq/L -2 to 2 mEq/L
Normal ABG Results (SI Units)
pH PaO2 PaCO2 O2 Saturation HCO3 Base Excess
7.35–7.45 10.6–12.6 kPa 4.66–5.98 kPa 95–100% 21–28 mmol/L -2 to 2 mmol/L
Critical Levels: pH: 7.25 or 7.55; PaCO2: 20 or 60; PaO2: 45; HCO3: 15 or 40; Base Excess:  3
. Collect in an air-free heparinized syringe. Send in ice slurry to lab immediately.
■ ABGs provide information about acid-base balance and the levels of O2 and CO2 in the blood.
■ ABG results may indicate decreased O2 levels (hypoxia), decreased or increased CO2 levels (hypo- or
hypercapnia), acidosis (decreased pH), alkalosis (increased pH), and the degree of compensation.
■ ABGs are drawn to establish the diagnosis and severity of respiratory failure and manage patients with
respiratory dysfunction, cardiac failure, renal or hepatic failure, trauma, multisystem failure, diabetic
ketoacidosis, sepsis, and other serious conditions.
■ An indicator of hydrogen ion concentration. Controlled primarily by the ratio of bicarbonate ions (HCO3
to carbonic acid (H2CO3). The body can tolerate only small changes in blood pH. Levels outside this range
lead to coma and death because vital proteins lose structural integrity and function.
■ Acidosis and alkalosis refer to processes that alter the pH of blood.
■ Metabolic acidosis, metabolic alkalosis, respiratory acidosis, and respiratory alkalosis are the four ways in
which pH is altered. A patient often has two processes occurring simultaneously; for example, a
metabolic acidosis and a respiratory alkalosis. One process dominates and the other partially
■ In metabolic processes, the bicarbonate concentration in the blood changes. Bicarbonate is a
base controlled by the kidneys. Decreases in bicarbonate result in metabolic acidosis and
increases result in metabolic alkalosis.
■ In respiratory processes, blood pH is affected by carbon dioxide (CO2) levels. Though CO2 is
technically a gas, it is regarded as a respiratory acid—the only acid that can be exhaled.  It is the
waste product of cellular metabolism and is carried by the blood to the lungs for excretion. If the
lungs are unable to excrete it, CO2 levels rise. Increased CO2 levels in the blood result in
respiratory acidosis.  Decreased levels of carbon dioxide result in respiratory alkalosis.
■ An indirect measure of oxygen content. Measures the tension (or partial pressure) of oxygen in
the blood.
■ Measures the partial pressure of carbon dioxide in the blood. CO2 content is controlled by the
lungs, and PCO2 is therefore a measure of how adequately the lungs are ventilating.
O2 Saturation
■ Indicates the oxygen content of the blood expressed as a percentage.
HCO3-■ Indicates the bicarbonate ion concentration in the blood, which is regulated by the kidneys. It is
directly related to blood pH.
Base Excess/Deficit
■ A calculated result that indicates the number of buffering anions in the blood and reflects the
metabolic component of the patient’s acid-base balance.LABS
Aspartate Aminotransferase (AST)
Adult, child: 0–35 U/L; SI units: 0–0.58 kat/L
Newborn: 15–60 U/L
. Red-top tube.
■ Enzyme found in cardiac muscle, liver, and skeletal muscle.
■ Used primarily to evaluate patients with symptoms of liver
disease (jaundice, liver enlargement, fatigue, weight loss,
ascites, etc.).
B-type Natriuretic Peptide
0–100 pg/mL SI units: 0–100 ng/L
. Lavender-top plastic tube. Put on ice immediately. Specimen may
need to be fasting; check with lab.
■ Secreted by ventricular myocardium; acts as a vasodilator and
increases renal excretion of sodium and water.
■ Suppresses sympathetic tone and the renin-angiotensin
■ Aids in the diagnosis of CHF.
Bence Jones Protein (Immunofixation [IFE], Protein
. Random or 24-hr urine collection. Refrigerate during collection.
■ Identifies types of proteins abnormally present in urine.
■ Used in the diagnosis of monoclonal gammopathies,
lymphoproliferative diseases, multiple myeloma,
macroglobulinemia of Waldenström, and amyloidosis.
Bilirubin, Total, Direct, Indirect
Adult, child: Total: 0.3–1 mg/dL; SI units: 1.7–20.5 mol/L
Direct: 0.1–0.3 mg/dL; SI units: 1.7–5.1 mol/L
Indirect: 0.1–0.8 mg/dL; SI units: 1.7–12 mol/L
Newborn: 1–12 mg/dL; SI units: 17.1–205 mol/L
Critical Level: Newborn: 15 mg/dL; SI units: 257 mol/L
. Red-top tube.
■ Bilirubin is a by-product of the the breakdown of hemoglobin.
■ Most bilirubin is chemically attached (conjugated) to another
substance. This is called direct bilirubin.  Unconjugated
builirubin is called indirect bilirubin. Conjugated bilirubin is
excreted in bile.
■ High bilirubin levels cause jaundice and are seen in liver disease
and biliary obstruction.
■ In newborns, elevated bilirubin occurs with Rh or ABO
incompatibility. Brain jaundice (kernicterus) develops at higher
levels and can result in mental retardation, cerebal palsy, or
Bilirubin, Urine
. Random urine. Protect from light.
■ Used to detect bilirubin in the urine, which is not normal and
indicates liver or biliary disease.
Bleeding Time
1–9 min (Ivy)
. Assessed by making a 1mm deep incision and noting time it takes
for bleeding to stop.
■ Prolonged bleeding time may indicate defective platelet function,
thrombocytopenia, von Willebrand’s disease.
■ Affected by drugs including dextran, indomethacin, and NSAIDs.
Blood Cultures
. Blood culture bottles—one aerobic and one anaerobic.
■ Isolate and identify potentially pathogenic organisms causing
bacteremia; establish the diagnosis of endocarditis.
■ Obtained when sepsis, meningitis, osteomyelitis, arthritis,
bacterial pneumonia, fever of unknown origin, or occult abscess
is suspected.
■ Strict aseptic technique and skin preparation are essential to
■ Several sets of blood cultures are taken.
Blood Urea Nitrogen (BUN)
Adult: 10–20 mg/dL; SI units: 3.6–7.1 mmol/L
Child: 4–16 mg/dL; SI units: 1.4–5.7 mmol/L
Critical Levels:
40 mg/dL (not dehydrated/no history of renal disease)
100 mg/dL (patient with history of renal disease)
20 mg/dL increase in 24 hr (indicates acute renal failure)
. Red-top tube.
■ BUN, a by-product of protein metabolism, is excreted
primarily by the kidneys and therefore reflects kidney
■ Elevated BUN (azotemia) occurs in most renal diseases;
also rises with GI bleeding, dehydration, high protein diet,
and CHF.
CD4/CD8 Ratio
See Lymphocyte Immunophenotyping.
C. difficile toxin (Pseudomembranous Colitis Toxic Assay)
. Small amount of stool in a sterile container.
■ Assist in the diagnosis of antibiotic-related diarrhea.
■ The C.difficile bacterium releases a toxin that causes the
epithelial lining of the colon to become necrotic.
C-reactive Protein (CRP); High-sensitivity CRP (hs CRP)
10 mg/L; SI units: 10 mg/L
. Red-top tube. Some labs require a fasting sample.
■ Abnormal protein manufactured in the liver in response to
inflammation and infection. Useful in evaluating
autoimmune and infectious diseases and in monitoring
treatment effectiveness.
■ CRP levels usually rise to 100 mg/L or more in the presence
of inflammation and infection. For this purpose, the plain
CRP test is used because it measures CRP in the 10–1000
mg/L range.
■ The high-sensitivity CRP test is used to assess risk of
atherosclerosis in otherwise healthy adults. It measures
CRP in the 0.5–10 mg/L range. Higher levels within this
range are associated with an increased risk of
CA 15–3
30 U/mL SI units: 30 kU/L
. Red-top tube.
■ Tumor marker monitored to assess response to treatment
of invasive breast cancer.
■ Assess for recurrence of the disease.
■ Relative fall of CA 15–3 value reflects treatment
CA 19–9
37 U/mL; SI units: 37 kU/L
. Red-top tube.
■ Tumor marker monitored to assess gastrointestinal,
pancreatic, liver, and colorectal malignancies.
■ Monitor response to cancer treatment and assess for
CA 125
0–35 U/mL; SI units: 35 kU/L
. Red-top tube.
■ Elevated in 80% of women with ovarian cancer.
■ Tumor marker monitored to assess effectiveness of
treatment and assess for recurrence.
Adult: Males: 40 pg/mL; SI units: 40 ng/L. Females: 25
pg/mL; SI units: 25 ng/L
. Green-top tube or chilled red-top tube. Specimen must be
■ Hormone produced by the thyroid gland.
■ Calcitonin reduces circulating calcium levels by increasing
calcium’s deposition in bone.
■ Used in the assessment of thyroid medullary cancer, lung
cancer, pernicious anemia.
Calcium, Ionized
Adult: 4.4 to 5.3 mg/dL; SI units: 1.05–1.3 mmol/L
Child: 4.4 to 6.0 mg/dL; SI units: 1.2–1.38 mmol/L
Critical levels:  6.29 mg/dL; SI units: 1.57 mmol/L or 3.1
mg/dL; SI units:  0.78 mmol/L
. Red-top tube.
■ Ionized calcium is the metabolically active form of calcium.
■ Level is affected by the albumin level, blood pH, phosphate,
magnesium, and bicarbonate levels.
■ Decreased by factors that bind calcium (citrate from
transfused blood or free fatty acids from total parenteral
nutrition [TPN]).
■ Decreased levels affect heart rhythm and neurologic status.
Calcium, Total
Adult: 8.2 to 10.5 mg/dL; SI units: 2.05–2.54 mmol/L
Child: 8.6–11.2 mg/dL; SI units: 2.15–2.79 mmol/L
Critical levels: 12 mg/dL; SI units: 2.99 mmol/L (coma, death).
7mg/dL; SI units: 1.75 mmol/L (tetany, death)
. Red-top tube.
■ 50% of calcium in blood is bound to albumin and is inactive;
the other 50%, called free or ionized calcium, is metabolically
active. Total calcium is a measurement of both bound and free
■ Assess for diseases of the parathyroid gland or kidneys.
Carbon Dioxide Content  (CO2)
Adult: 22–30 mEq/L; SI units: 22–30 mmol/L
Child: 20–28 mEq/L; SI units: 20–28 mmol/L
. Red-top tube.
■ Used in the evaluation of pH and electrolytes.
■ Blood CO2 measures the total amount of carbon dioxide in the
blood (bicarbonate [HCO3]], dissolved carbon dioxide gas
[CO2], and carbonic acid [H2CO3]). It is essentially a measure
of serum bicarbonate (HCO3) because 95% of CO2 is present
as HCO3.
■ Do not confuse with PaCO2, which measures the partial
pressure of carbon dioxide.
■ Increased: compensation for respiratory acidosis and
metabolic alkalosis. Decreased: compensation for respiratory
alkalosis and metabolic acidosis.
Carbon Monoxide (Carboxyhemoglobin)
Nonsmoker: 2%; Smoker: 9%; Toxic: 15%
Critical Levels: 20%
. Lavender-top tube.
■ Used to evaluate patients exposed to smoke, fumes, and fires.
■ Levels 20% cause dizziness and headache; 30%,
tachycardia, hypotension, and confusion; >60%, coma and
Carcinoembryonic Antigen (CEA)
Nonsmokers: 3 ng/mL; SI units 3 g/L
Smokers: 5 ng/mL; SI units 5 g/L
. Red-top or lavender-top tube, depending on lab.
■ Used to monitor treatment response and possible recurrence
of breast, colon, or pancreatic cancer.
■ Not a screening test since CEA can be elevated in benign
diseases and smokers.
■ Heparin use interferes with results. Hold for 2 days prior to
Cardiac Biomarkers
See individual tests for reference ranges.
■ Enzymes, proteins, and hormones used in the diagnosis of acute
myocardial infarction.
■ Biomarkers rise, peak, and return to normal in predictable time
frames allowing health care providers to monitor the progress of
the infarction.
■ These laboratory tests include:
◆ Albumin cobalt binding
◆ Creatinine kinase (CK) (or creatine phosphokinase) and CK-MB
isoenzyme (less frequently used)
◆ Troponin (most widely used to assess heart damage)
◆ Myoglobin (less frequently used; may be ordered with
◆ B-type natriuretic peptide (used to assess heart function)
Catecholamines and Vanillylmandelic Acid (VMA)
Epinephrine: 0–20 g/24 hr; SI units: 0–109 nmol/day
Norepinephrine: 15–80 g/24 hr; SI units: 89–473 nmol/day
Dopamine: 65–400 g/24 hr; SI units: 424–2612 nmol/day
VMA: 6.8 mg/24 hr; SI units: 35 mol/24 hr
Epinephrine: 4–10 yrs: 10 g/24 hr; SI units: 54.6 nmol/day
Norepinephrine: 4–10 yr: 8–65 g/24 hr; SI units: 47–384 nmol/day
Dopamine: 1–4 yrs: 10–260 g/24 hr; SI units: 65–1698 mol/L/day
VMA: 2–18 yr: 1–5 mg/ 24 hr; SI units: 30 mol/24 hr
. 24-hr urine collection.
■ Used to screen for neuroendocrine tumors including
■ Test is affected by multiple foods and drugs. Check with lab
about withholding medications or changing diet prior to and
during the test.
Cerebrospinal Fluid Analysis (CSF Analysis)
Pressure: 50–180 mm H2O
Appearance: Clear and colorless
Total protein: 15–45 mg/dL; SI units: 150–450 mg/L
Protein electrophoresis:
◆ Prealbumin: 2–7%
◆ Albumin: 56–76%
◆ Alpha1 globulin: 2–7%
◆ Alpha2 globulin: 4–12%
◆ Beta globulin: 8–18%
◆ Gamma globulin: 3–12%; SI units: 0.3–0.12
◆ Oligoclonal bands: none
◆ IgG: 3.4 mg/dL;  SI units: 34 mg/L
Glucose: 50–80 mg/dL; SI units: 2.8–4.4 mmol/L
Cell count: 0–5 WBCs; no RBCs
Chloride: 118–132 mEq/L; SI units: 118–132 mmol/L
Lactate dehydrogenase: 10% of serum level
Lactic acid: 10–20 mg/dL; SI units: 1.1–2.2 mmol/L
Cytology: No malignant cells
Culture: No growth
Gram stain: Negative
India ink: Negative
VDRL: Nonreactive
Critical Values: Positive Gram’s stain, India ink preparation, or
. Sterile test tubes, numbered in the order they were filled.
Send to lab immediately. Do not refrigerate.
■ Obtained by lumbar puncture, which requires careful
patient preparation, postprocedure care, and informed
■ Used to aid in the diagnosis of meningitis, intracranial or
subarachnoid bleeding, brain injury, neurosyphilis,
degenerative brain diseases, CNS cancer or metastases,
autoimmune disorders, multiple sclerosis, and other
Chlamydia Group Antibody
Negative: 0.91; Equivocal: 0.91–1.09; Positive: 1.10
. Red-top tube.
■ Used in the diagnosis of chlamydial infection.
■ Detects IgG antibodies to C. trachomatis, C. pneumoniae, and
C. psittaci.
■ Other methods, including swabs from infected areas for C.
trachomatis, and urine samples are also used to detect
Chlamydia infections.
Chloride (Cl)
Adult: 96–106 mEq/L; SI units: 96–106 mmol/L
Child: 90–110 mEq/L; SI units: 90–110 mmol/L
Critical levels: 80 mEq/L or 115 mEq/L
. Red-top or green-top tube.
■ Aids in maintenance of electrical neutrality, fluid and acid-base balance, and osmolality of body fluids (with sodium).
Assessed with other electrolytes.
■ Decreased in vomiting, gastric suctioning, ketoacidosis, renal
disease with loss of sodium.
■ Increased with diarrhea, dehydration, total parenteral
Cholesterol, Total; High-density Lipoprotein Cholesterol (HDL,
HDL-C); Low-density Lipoprotein Cholesterol (LDL, LDL-C); Very
Low-density Lipoprotein (VLDL)
Total Cholesterol
Adult: 200 mg/dL; SI units: 5.2 mmol/L
Child: 125–200 mg/dL; SI units: 3.27–5.2 mmol/L
HDL Cholesterol
Adult: 50 mg/dL; SI units: 1.40 mmol/L
LDL Cholesterol
Adult: 100 mg/dL; SI units: 2.56 mmol/L
VLDL Cholesterol
. Red-top tube. Fasting sample; no alcohol for 24 hr prior to test.
■ Blood lipids synthesized in the liver and integral to the
formation of cell membranes, bile salts, and hormones.
■ Implicated in atherosclerosis and MI.
■ HDL levels 60 mg/dL are protective against heart disease.
Coagulation Factors
◆ Factor II (prothrombin)
◆ Factor V (proaccelerin or labile factor)
◆ Factor VII (proconvertin or stable factor)
◆ Factor VIII (antihemophilic factor A, antihemophilic globulin)
◆ Factor IX (antihemophilic factor B, plasma thromboplastin
component, Christmas factor)
◆ Factor X (Stuart-Prower factor)
◆ Factor XI (plasma thromboplastin antecedent)
◆ Factor XII (Hageman factor)
One-stage Assay: Intrinsic Coagulation System
Factor VIII: 55–145% of control
Factor IX: 60–140% of control
Factor XI: 65–135% of control
Factor XII: 50–150% of control
One-stage Assay: Extrinsic Coagulation System
Factor II: 50–200% of control
Factor V: 50–150% of control
Factor VII: 65–135% of control
Factor X: 45–155% of control
. Blue-top tube.
■ Coagulation is a cascade of events involving over 30 different
substances. It causes circulating substances within the blood
to coagulate into a gel, forming a protective barrier over
injured body tissues or blood vessels.
■ Although the completion of clotting follows a common path,
clotting can be initiated by either the intrinsic or the extrinsic
pathway. Both pathways are usually triggered in tissue or
blood vessel injury; however, in hemophilic diseases,
alterations in intrinsic factors cause the bleeding disorder. In
DIC, multiple clotting factor abnormalities occur.
■ In addition to the above eight factors, tissue factor (tissue
thromboplastin) released by damaged cells, thrombin,
fibrinogen, and calcium are integral to clot formation.
■ Clotting factors are assessed to determine the cause of
bleeding disorders. Fibrin degradation products, D-dimers,
and plasminogen are also measured in coagulopathies and
represent the process of clot dissolution or the fibrinolytic
Cold Agglutinin Titer
Negative (1:16)
. Red-top tube. Do not refrigerate.
■ Cold agglutinins are antibodies that cause red blood cells to
agglutinate (clump together).
■ Used in the diagnosis of primary atypical pneumonia,
Mycoplasma pneumoniae, hemolytic anemia, gangrene,
Raynaud’s disease, and other diseases.
Complement, Total
Adult: 75–160 U/mL; SI units: 75–160 kU/L
. Red-top tube.
■ Proteins involved in immunological and inflammatory
■ Diagnose angioedema; assess treatment/status of various
diseases including systemic lupus erythematosus nephritis
and other types of nephritis.
■ Deficiency associated with increased susceptibility to
Complement C3 and C4
C3: 55–120 mg/dL; SI units: 0.55–1.2 g/L
C4: 20–50 mg/dL; SI units: 0.2–.05 g/L
. Red-top tube.
■ Commonly assessed components of the complement
■ Increased levels associated with rheumatoid arthritis, some
cancers, and acute viral hepatitis.
■ Decreased levels associated with SLE, glomerulonephritis,
DIC, gram-negative sepsis.
Complete Blood Count with Differential (CBC with diff)
Test Conventional SI Units
Red Blood Cell
Hemoglobin (Hgb)
Hematocrit (Hct)
White Blood Cells
WBC Differential
◆ Neutrophils,
◆ Neutrophils,
◆ Lymphocytes
◆ Monocytes
◆ Eosinophils
◆ Basophils
Critical levels:
Hgb: 5 g/dL or 20 g/dL
Hct: 15% or 60%
WBC: 500 mm3
or 50,000/ mm3
Platelets: 50,000  or 999,000/mm3
. Lavender-top tube.
■ A CBC reveals
◆ Information about general health.
◆ Number of red blood cells (RBC).
Male: 4.6–6.2  106
cells /L
Female: 4.2–5.9  106
cells / L
Male: 13–18 g/dL
Female: 12–16 g/dL
Male: 45–52%
Female: 37–48%
80 to 100 m3
27 to 31 pg/cell
32 to 36 g/dL
4.6–6.2  1012
cells /L
4.2–5.9  1012
cells /L
Male: 130–180 g/L
Female: 120–160 g/L
Male: 0.45–0.52
Female: 0.37–0.48
80 to 100 m3
27 to 31 pg/cell
32 to 36 g/dL
4.3–10.8  109
150–450 x 109
◆ Number of white blood cells (WBC) and differential (see
White Blood Cells for more information).
◆ Total amount of hemoglobin in the blood (Hgb).
◆ Fraction of blood composed of red blood cells (Hct).
◆ Volume of Hgb in each RBC (MCV [mean corpuscular
◆ Weight of the Hgb in each RBC (MCH [mean corpuscular
◆ Proportion of Hgb contained in each RBC (MCHC [mean
corpuscular hemoglobin concentration]).
◆ Number of platelets, which are critical to clot formation (see
Platelets for more information).
■ MCV, MCH, and MCHC values are useful in the diagnosis of
various types of anemia. See below for description of
Types of Anemia
Type of Anemia Possible Causes
(normal cell size; normal
amount of Hgb)
(small cell size; low amount
of Hgb)
(small cell size; normal
amount of Hgb)
(large cell size; normal
amount of Hgb)
◆ Microcytic— MCV less than normal (80 fL)
◆ Normocytic— MCV within normal range (80–100 fL)
◆ Macrocytic— MCV greater than normal (100 fL)
◆ Hypochromic—MCH less than normal (27 pg)
◆ Normochromic—MCH within normal range (27–31 pg)
◆ Hyperchromic—MCH greater than normal (31 pg)
Acute blood loss, aplastic anemia,
prosthetic heart valves, sepsis,
Iron deficiency, lead poisoning,
Erythropoietin deficiency
secondary to renal failure
Chemotherapy, folate deficiency,
vitamin B12 deficiency
Coombs’ Test, Direct  (Direct Antiglobulin)
Negative; no agglutination
. Lavender-top tube.
■ Assess for immunoglobulins (antibodies) on surface of red
blood cells
■ Positive results occur in hemolytic transfusion reactions,
hemolytic anemias, erythroblastosis fetalis
Coombs’Test, Indirect (Indirect Antiglobulin, Autoantibody Test)
. Red-top tube.
■ Part of a cross-match for blood transfusion.
■ Positive result indicates incompatibility.
Cortisol, Free
Adult: 50 g/24; SI units: 138 nmol/day
Child: 38 g/24 hr; SI units: 104 nmol/day
. 24-hr urine collection.
■ Used to screen for adrenal hyperfunction.
■ Result from urinary free cortisol test is a better indication of
cortisol secretion than a single plasma level.
■ Best test for diagnosing Cushing’s syndrome.
Cortisol, Plasma
Adult:  8 AM–10 AM: 5–23 g/dL; SI units: 138–635 mmol/L.
4 PM–6 PM: 3–13 g/dL; SI units:  83–359 mmol/L
Chlid:  8 AM–10 AM: 15–25 g/dL
4 PM–6 PM: 5–10 g/dL
. Green-top tube.
■ Powerful glucocorticoid secreted by the adrenal cortex in
response to ACTH. Higher in the morning.
■ Affects gluconeogenesis, fat and protein metabolism; aids
in regulation of immune system; is increased during
physical or emotional stress.
■ Assessed in the evaluation of Cushing’s syndrome and
Addison’s disease.
Creatinine Phosphokinase, (CPK, Creatine Kinase, CK);
CPK Isoenzymes
Adult: Male: 55–170 U/L; SI units: 55–170 U/L. Female: 30–135 U/L;
SI units: 30–135 U/L
Newborn: 68–580 U/L
CPK-MM: 100%; CPK-MB: 0%; CPK-BB: 0%
. Red-top tube.
■ CPK is an enzyme critical to intracellular energy.
■ The MB isoenzyme is a cardiac marker (but is not as specific
as troponin). Elevations occur in acute MI and are used in the
diagnosis of MI.
■ CPK-MB ratio to total CPK is calculated to increase diagnostic
accuracy. A ratio of 2.5 correlates with cardiac damage.
■ MM elevations occur in crush injuries, seizures, malignant
Creatinine, Serum
Adult: Male: 0.6–1.2 mg/dL; SI units: 53–106 mol/L. Female: 0.5–1.1
mg/dL; SI units: 44–97 mol/L
Child: 0.3–0.7 mg/dL
. Red-top tube.
■ Breakdown product of creatine phosphate in muscle.
■ Produced at a constant rate by the body and excreted by the
kidney. Blood level rises in renal impairment.
■ Creatinine level is a sensitive indicator of renal function but is
dependent on kidney function and muscle mass. Patients with
decreased muscle mass do not exhibit a rise in creatinine
levels as readily as those with more muscle mass and should
have an estimated glomerular filtration rate (GFR) reported as
Creatinine, Urine
1–2 g/24 hr; SI units: 8.8–17.7 mmol/day
. 24-hr urine collection. Refrigerate.
■ Creatinine is a by-product of muscle breakdown. It is filtered
(removed from plasma) by the kidneys and excreted in the
■ Elevated levels of creatinine indicate impaired renal function.
Creatinine Clearance
Male: 107–139 mL/min; SI units: 1.78–2.32 mL/s. Female: 85–105
mL/min; SI units: 1.45–1.78 mL/s.
. Timed urine sample (12 or 24 hr) with a blood sample taken
the morning of or sometime during the test.
■ Creatinine clearance refers to the amount of blood that can
be cleared of creatinine in 1 min.
■ It is calculated using the volume of urine, the amount of
creatinine excreted, and the amount of creatinine in the
■ It is used to determine safe dosing of nephrotoxic drugs.
Creatinine clearance of 10–20 mL/min is indicative of renal
failure and the need for dialysis.
 0.4% or none detected
■ Abnormal proteins present in various immune, hematologic,
collagen vascular, and oncologic disorders.
■ Levels 5 mg/mL are associated with multiple myeloma and
■ Levels between 1 and 5 mg/mL are associated with
rheumatoid arthritis.
Cystatin C
Adult: 0.5–1 mg/L
Child: 0–3 mo: 0.8–2.3 mg/L; 4–11 mo: 0.7–1.5 mg/L;
1–17 yr: 0.5–1.3 mg/L
. Red-top tube.
■ A cysteine protease inhibitor that is freely filtered
(removed) by the glomeruli and thus can be used to assess
for changes in glomerular filtration rate.
■ High levels of cystatin C suggest impaired renal function.
■ It is thought to be superior to creatinine as a marker of
glomerular filtration rate because it is not affected by
muscle mass, diet, or acute inflammatory processes.
10–100 mg/24 hr
. 24-hr urine collection.
■ Used to detect cystinuria or identify cause of kidney stones.
Cytomegalovirus (CMV) Antibodies
IgM  1:8; IgG  1:16
. Red-top tube.
■ CMV is a virus in the herpes family.
■ Active infection significant in pregnant women, potential
transplant patients and immunocompromised patients.
■ If active infection is suspected, a second sample is assessed
in 10–14 days.
Negative (250 ng/mL; SI units: 250 g/L)
. Blue-top tube.
■ A fibrin degradation product produced only after a clot has
formed and is in the process of being broken down.
■ Used in the diagnosis of deep vein thrombosis (DVT),
pulmonary embolism (PE), or disseminated intravascular
coagulation (DIC).
Dexamethasone Suppression Test
Low Dose
Overnight: 8 AM plasma cortisol: 5 g/dL
Standard: Urinary free cortisol on day 3: 10 g/day
High Dose
Overnight: 50% reduction in plasma cortisol.
Standard: 90% reduction in urinary free cortisol.
. Red-top tube.
■ Administration of dexamethasone suppresses ACTH and
should suppress cortisol levels in healthy people.
■ Helpful in determining cause of increased cortisol levels
(adrenal tumor, pituitary tumor, or ectopic ACTH-producing
Drug Levels, Therapeutic and Toxic
Conventional (US System of Measurements)
Drug Therapeutic Level Toxic Level
aminocaproic acid
bepridil HCl
chloral hydrate
5–20 g/mL
10–50 ng/mL
peak: 20–30 g/mL
trough: 4–8 g/mL
100–400 g/mL
10–20 g/mL
0.5–2.5 g/mL
120–150 ng/mL
200–400 ng/mL
200–500 ng/mL
1–2 ng/mL
5–12 g/mL
2–12 g/mL
10–20 g/mL
1–5 g/mL
50–300 ng/mL
75–250 g/mL
15–60 ng/mL
100–300 ng/mL
150–300 ng/mL
0.5–2 mg/L
0.8–2 ng/mL
50–200 ng/mL
2–5 g/mL
150–300 ng/mL
40–100 g/mL
0.2–1 g/mL
peak: 6–10 g/mL
trough:  2 g/mL
40 g/mL
75 ng/mL
peak: 35 g/mL
trough: 10 g/mL
400 g/mL
20 g/ml
2.5 g/mL
500 ng/ml
500 ng/mL
500 ng/mL
2 ng/mL
12 g/mL
20 g/mL
25 g/mL
5 g/mL
750 ng/mL
250 g/mL
80 ng/mL
85 or 500 ng/mL
500 ng/mL
3 mg/L
2 ng/mL
200 ng/mL
7 g/mL
400 ng/mL
150 g/mL
1 g/mL
peak: 12 g/mL
trough: 2 g/mL
(Continued on following page)
Drug Therapeutic Level Toxic Level
mezlocillin sodium
tocainide HCl
valproic acid
3–20 ng/mL
1–30 ng/mL
150–300 ng/mL
20–25 g/mL
1.5–5 g/mL
0.5–1.5 mEq/L
0.4–0.7 g/mL
 0.01 mol
0.5–2 g/mL
35–45 g/mL
150–250 ng/mL
10–80 ng/mL
0.028–0.05 g/mL
0.025–0.1 g/mL
50–150 ng/mL
15–30 g/mL
10–20 g/mL
5–12 g/mL
4–10 g/mL
0.5–3 g/mL
50–100 ng/m
2–5 g/mL
10–30 mg/dL
10–20 g/mL
peak: 6–10 g/mL
trough:  2 g/mL
4–10 g/mL
500–2000 ng/mL
50–100 g/mL
peak: 20–40 g/mL
trough: 5–10 g/mL
0.08–0.3 g/mL
42 ng/mL
100 ng/mL
500 ng/mL
35 g/mL
5 g/mL
1.5 mEq/L
1 g/mL
10 mol in 24 hr
2 g/mL
45 g/mL
250 ng/mL
200 ng/mL
0.05 g/mL
0.1 g/mL
500 ng/mL
40 g/mL
20 g/mL
12 g/mL
10 g/mL
3 g/mL
150 ng/mL
6 g/mL
35 mg/dL
20 g/mL
peak: 12 g/mL
trough: 2g/mL
12 g/mL
4000 ng/mL
100 g/mL
peak: 80 g/mL
trough: 10 g/mL
0.3 g/mL
SI Units (International System of Units)
Drug Therapeutic Range Toxic Level
salicylic acid
valproic acid
peak: 34–51 mol/L
trough: 7–14 mol/L
433–903 nmol/L
21–51 mol/L
40–200 nmol/L
281–1125 nmol/L
0.35–3.5 nmol/L
1–2.6 nmol/L
9–18 mol/L
280–708 mol/L
0.5–2.4 mol/L
peak:12–21 mol/L
trough:4 mol/L
610–1670 nmol/L
6–21 mol/L
0.5–1.5 mmol/L
190–570 nmol/L
86–172 mol/L
40–80 mol/L
23–55 mol/L
17–42 mol/L
6–15 mol/L
1–2 mmol/L
28–111 mol/L
peak: 13–21 mol/L
trough:  4 mol/L
350–700 mol/L
peak: 14–28 mol/L
trough: 3–7 mol/L
peak: 60 mol/L
805 nmol/L
51 mol/L
260 nmol/L
1500 nmol/L
17.5 nmol/L
2.6 nmol/L
 21 mol/L
1062 mol/L
2.4 mol/L
peak: 21 mol/L
1785 nmol/L
39 mol/L
2 mmol/L
1900 nmol/L
172 mol/L
158 mol/L
55 mol/L
51 mol/L
29 mol/L
3.6 mmol/L
111 mol/L
peak: 21 mol/L
1386 mol/L
peak: 28 mol/L
. Red-top tube.
■ Drug levels are obtained both to enhance therapeutic
efficacy and to assess for toxicity/overdose/poisoning.
■ Therapeutic drug monitoring (TDM) is the measurement of
serum drug levels so that dosages may be adjusted to
achieve optimum clinical benefit.
■ Therapeutic drug monitoring is used with
◆ cardiac glycosides (e.g., digoxin)
◆ antiarrhythmics (e.g., lidocaine, procainamide)
◆ anticonvulsants (e.g., phenytoin, carbamazepine)
◆ lithium
◆ theophylline
◆ aminoglycoside antibiotics (gentamicin, tobramycin)
◆ salicylates
■ For TDM, blood samples must be obtained at the
appropriate time and after sufficient number of doses have
been administered for valid interpretation of results.
■ Peak and trough levels are drawn with some drugs,
especially antibiotics. Peak levels are drawn at the point of
maximum drug absorption; trough levels are drawn just
before the next dose.
Electrolytes, Serum
See individual tests for normal values.
. Red-top tube.
■ Electrolytes are minerals present in body tissues and blood
as dissolved salts.
■ They are electrically charged particles that help maintain
fluid and acid-base balance. They help move nutrients into
cells and waste products out.
■ An electrolyte panel measures sodium (Na
), potassium
), chloride (Cl-), and bicarbonate (HCO3-), which is
measured indirectly as CO2.
■ See individual tests and Anion Gap for more information.
Electrolytes, Urine
Conventional Units SI Units
. 24-hour urine collection
■ Provides information about hydration status, the kidneys’ ability
to conserve or excrete sodium.
■ Calcium levels are increased in hyperthyroidism, immobilization,
multiple myeloma, Paget’s disease, and bone metastases.
Erythropoietin (EPO)
5–35 IU/L
. Red-top tube.
■ Hormone produced by the kidney to stimulate RBC production.
■ Decreased in patients with renal disease, primary polycythemia.
Estradiol, Serum (Estrogen Fraction)
Adult: Female: Follicular phase: 20–150 pg/mL; Midcycle phase:
100–500 pg/mL; Luteal phase: 60–260 pg/mL; Pregnancy: 1st
tri: 1–5
ng/mL; 2nd tri: 5–15 ng/mL; 3rd tri: 10–40 ng/mL; Postmenopause:
30 pg/mL. Male: 15–50 pg/mL
. Red-top tube.
■ An estrogen fraction useful in evaluating fetal well-being,
menstrual and fertility problems in women, precocious puberty
in girls, gynecomastia.
■ Used to assess amenorrhea to determine if cause is menopause,
pregnancy, or a medical problem.
■ Serial measurements are used to monitor follicle development in
the ovary prior to in vitro fertilization.
■ Estrone, the major estrogen after menopause, and estriol, the
major estrogen in pregnant women, are the other major
30–280 mEq/day
110–250 mEq/day
40–80 mEq/day
Male: 275 mg/day;
Female: 250 mg/
0.9–1.3 g/day
150 mg/day
30–280 mmol/day
110–250 mmol/day
40–80 mmol/day
Male: 6.8 mmol/day;
Female: 6.2
29–42 mmol/day
3–4.3 mmol/day
Ethanol (blood alcohol)
. Red-top tube. Use povidone-iodine swab not alcohol to clean
venipuncture site.
■ Levels 0.8% are considered to be proof of intoxication in
most states.
Febrile Agglutinin Titer
Negative (1:80)
. Red-top tube. Do not warm.
■ Febrile agglutinins are antibodies that cause RBCs to
agglutinate (clump together) at high temperatures.
■ Febrile agglutinin titers are used in the diagnosis of some
bacterial infections (salmonellosis, tularemia, Rocky
Mountain spotted fever, typhus, brucellosis).
Fecal Fats (Fecal Lipids)
2–6 g/24 hr; SI units: 7–21 mmol/day
. 72-hr stool collection. Keep refrigerated during collection.
■ Assist in the diagnosis of malabsorption or pancreatic
■ A high fat diet should be eaten for 3 days before and
throughout the collection time period and should refrain
from laxative use.
Fecal Occult Blood (FOB, Stool for Occult Blood)
. Stool sample
■ Used to detect microscopic bleeding into the GI tract.
■ Routine screening test for patients over 50 years old.
■ Positive in ulcers, polyps, hemorrhoids, tumors,
inflammatory bowel disease, diverticulosis, and other
disorders of the GI tract.
Adult: Female: 10–150 ng/mL; SI units: 10–150 g/L. Male: 12–300
ng/mL; SI units: 12–300 g/L
Child 1 year: 7–140 ng/mL; SI units: 7–140 g/L
. Red-top tube.
■ Indicates available iron stores in the body.
■ Level below 10 ng/mL diagnostic of iron deficiency anemia.
Fibrin Split Products (Fibrin Degradation Products, FDP, FSP)
5 g/mL; SI units: 5 mg/L
. Blue-top tube (check with lab).
■ Blood clots in the vascular system stimulate the production
of plasmin, which breaks down clots into fibrin split
■ Elevated amounts of fibrin split products in the blood
indirectly indicate the presence of blood clots or a
fibrinolytic disorder such as DIC.
150–400 mg/dL; SI units: 1.5–4 g/L
Critical Levels: 100 mg/dL
. Blue-top tube.
■ Fibrinogen is essential to clot formation. Decreased
fibrinogen levels result in prolonged PT and PTT.
■ Usedful in diagnosis of DIC.
Folic Acid (Folate)
 2 ng/mL (radioimmunassay); SI units: 5 mmol/L
. Red-top tube.
■ Normal levels essential for properly functioning red and
white blood cells.
■ Decreased in malabsorption, malnutrition, liver disease,
Follicle-stimulating Hormone (FSH)
Adult: Males: 5–15 IU/L. Females: follicular or luteal phase: 5–20
IU/L, midcycle: 30–50 IU/L, postmenopause: 50 IU/L.
Prepubertal children: 6 IU/L
. Red-top tube.
■ Pituitary hormone involved in maturation of ovarian follicle
in women and spermatogenesis in men.
Gamma-Glutamyl Transpeptidase  (GGT, SGGT)
Adult: Male: 9–50 IU/L. Female: 8–40 IU/L
. Red-top tube.
■ Liver enzyme sensitive to biliary and liver disorders,
including alcoholic liver disease.
Fasting: 100 pg/mL; SI units: 47.7 pmol/L
Postprandial: 95–140 pg/mL; SI units: 45.3–66.7 pmol/L
. Red-top tube.
■ Hormone that stimulates secretion of gastric acid.
■ Elevated in pernicious anemia, Zollinger-Ellison syndrome,
stomach cancer, peptic ulcer, atrophic gastritis, renal
insufficiency, steroid administration, H2 blockers.
Adult: 50–100 pg/mL; SI units: 50–100 ng/L
Child: 0–148 pg/mL; SI units: 0–148 ng/L
. Lavender-top tube, chilled. Fasting sample.
■ Hormone secreted by the alpha cells of the islets of
■ Glucagon deficiency may occur with pancreatitis, pancreatic
cancer, cystic fibrosis.
■ Elevated glucagon levels occur with glucogonoma (cancer
of the alpha islet cells), diabetes, acute pancreatitis,
cirrhosis, stress, renal failure, rejection of transplanted
Glucose, Fasting
Adult: 70–105 mg/dL; SI units: 3.9–5.8 mmol/L
Child  2 years old: 60–100 mg/dL
Critical Levels: 50 or 400 mg/dL
. Red-top tube. Fasting sample.
■ Assessed to diagnose or monitor Type 1 and 2 diabetes.
■ An elevated fasting blood glucose level above 126 mg/dL
on at least two occasions typically indicates diabetes.
Glucose-6-Phosphate Dehydrogenase (G-6-PD) Screening Test
and G-6-PD Assay
Screening Test
7.0–20.5 U/g of hemoglobin; SI units: 0.45–1.29 mU/mol (reference
ranges vary with testing methodology)
. Lavender- or green-top tube.
■ G-6-PD is an enzyme found in RBCs; its function is to protect
hemoglobin from oxidation.
■ People with a G-6-PD deficiency are susceptible to hemolysis
when exposed to an oxidative stressor such as systemic
infections, septicemia, metabolic acidosis, and exposure to
oxidant drugs (aspirin, sulfa drugs, antimalarials, thiazide
diuretics, quinidine, antipyretics, sulfanomides,
chloramphenical, phenacetin, probenicid, and tolbutamide).
Glucose Tolerance Test, Standard  Oral
Fasting: 126 mg/dL; SI units: 7 mmol/L
2-hr: 200 mg/dL; SI units 1.1 mmol/L
. Red-top tube. Fasting sample.
■ Blood glucose levels are assessed twice. The first is a fasting
sample, the second sample is taken 2 hr after ingestion of
75 g of glucose. Samples may be assessed at other times as
■ Useful for screening for gestational diabetes but usually
unnecessary for diagnosing diabetes as fasting blood glucose
126 mg/dL or a random blood glucose level 200 mg/dL is
ususally considered diagnostic.
Glycosylated Hemoglobin (A1C, GHb, Glycohemoglobin, HBA1)
Nondiabetic:  5%
Diabetes well controlled: 2.5–6%
Diabetes not well controlled:  8%
. Lavender-top tube.
■ Prolonged blood glucose elevation causes a greater
percentage of RBCs to become saturated with glucose
■ Used for monitoring average diabetic control for preceding 3
months as blood cells typically live for 2–3 months.
■ Asessed two times per year for patients with type 2 diabetes
not on insulin and four times per year for patients with type
1 or 2 diabetes on insulin.
Growth Hormone (GH, Human Growth Hormone [HGH],
Somatotropin Hormone [SH]), Growth Hormone Suppression
Test, and Growth Hormone Stimulation Test
Adult: Males: 5 ng/mL; SI units: 5 g/L. Females: 10 ng/mL;
SI units: 10 g/L
Chlidren: 0–10 ng/mL; SI units: 0–10 g/L
Newborns: 10–40 ng/mL; SI units: 10–40 g/L
. Red-top tube.
■ Growth hormone is produced in episodic bursts by the
pituitary gland.
■ Assessed to evaluate possible dwarfism, growth retarda-tion, or gigantism in children and acromegaly in adults.
Adult: 60–270 mg/dL; SI units: 0.6–2.7 g/L
Newborn: 0–10 mg/dL; SI units: 0–0.1 g/L
. Red-top tube.
■ A protein produced by the liver that binds to hemoglobin
when it is released from hemolyzed RBCs.
■ Increased in many inflammatory diseases.
■ Decreased in hemolytic conditions (e.g., transfusion
reaction, anemia), hepatic disease.
Helicobacter pylori Antibody Titers
. Red-top tube.
■ Organism associated with gastic ulcer and gastritis.
■ Also may be assessed by culture, biopsy, or breath test.
Hematocrit (Hct)
Adult: Male: 45–52%; SI units: 0.45–0.52. Female: 37–48%;
SI units: 0.37–0.48.
Child: 1–6 yr: 30–40%; SI units: 0.30–0.40; 6–18 yrs: 32–44%;
SI units: 0.32–0.44
Critical Levels: 15% or 60%
. Lavender-top tube.
■ Hematocrit is the percentage of whole blood that is made up
of red blood cells. It is expressed as a percentage or a decimal
fraction. (A hematocrit value of 35% means that there is 35 mL
of red blood cells in 100 mL of blood.)
■ Increased in dehydration and increased production of RBCs.
■ Decreased in anemia, when RBC production is impaired or
there is increased destruction of RBCs, in chronic disease,
blood loss, and fluid volume excess.
■ See Complete Blood Count.
Hemoglobin (Hgb)
Adult: Male: 14–18 g/dL; SI units: 8.7–11.2 mmol/L. Female: 12–16
g/dL; SI units: 7.4–9.9 mmol/L.
Child: 1–14 ys: 11.3–14.4 g/dL; SI units: 113–144 mmol/L.
Critical Levels: 5 or 20 g/dL
. Lavender-top tube.
■ Hemoglobin is the main protein in erythrocytes. It carries
oxygen to and removes carbon dioxide from red blood cells.
■ Increased in dehydration, COPD, high altitudes, polycythemia
■ Decreased in fluid volume excess, hematologic cancers,
hemolytic disorders, blood loss, anemia.
■ See Complete Blood Count.
Hemoglobin Electrophoresis (Hemoglobinopathy Profile)
Hgb A1: 95–98%
Hgb A2: 2–3%
Hgb F: 0.8–2%; Newborn: 50–80%;  6 mo old: 1–2%
Hgb C, S, or E: 0%
. Lavender-top tube.
■ Used to screen for abnormal hemoglobins.
■ Hemoglobin A, A2 and F are normal hemoglobins. Hgb F is the
predominant fetal hemoglobin.
■ Hgb S is the predominant hemoglobin found in people with
sickle cell disease.
■ Hgb C and Hgb E produce mild hemolytic anemia and
splenomegaly. They are considered relatively benign. Hgb E is
extremely common in Southeast Asia.
Hepatitis Testing
. Red-top tube.
■ Screening for hepatitis A, B, C, D, or E.
■ May test for antigens, antibodies, IgG, or IgM
■ Viral hepatitis serologic testing patterns need to be interpreted
to determine if disease is active, acute, chronic, or historical
(carrier state).
Hexosaminidase, Total, A, A and B (Hex A)
Total Hexosaminidase
Noncarrier: 589–955 nmol/hr/mL; SI units: 9.9–15.9 U/L
Heterozygote: 465–675 nmol/hr/mL: SI units: 7.8–11.3 U/L
Tay-Sachs homozygote: 1027 nmol/hr/mL; SI units: 17.2 U/L
Hexosaminidase A
Noncarrier: 456–592 nmol/hr/m; SI units: 7.2–9.9 U/L
Heterozygote: 197–323 nmol/hr/mL; SI units: 3.3–5.39 U/L
Tay-Sachs homozygote: 0 nmol/hr/mL; SI units: 0 U/L
Hexosaminidase B
Noncarrier: 12–32 nmol/hr/mL; SI units: 0.2–0.54 U/L
Heterozygote: 21–81 nmol/hr/mL; SI units: 0.35–1.35 U/L
Tay-Sachs homozygote: 305 nmol/hr/mL; SI units: 5.1 U/L
. Red-top tube
■ Hexosaminidase is an enzyme necessary for metabolism of
gangliosides. Deficiency results in accumulation of
gangliosides in the brain.
■ Used to diagnose Tay-Sachs disease, which is caused by a lack
of hexosaminidase A and results in mental retardation,
blindness, weakness, and death by age 5.
■ Sandhoff’s disease is a variant of Tay-Sachs and results from a
deficiency of both hexosaminidase A and B.
High-density Lipoprotein Cholesterol
See Cholesterol.
4–17 mol/L
. Red-top tube
■ Elevated levels are a risk factor for coronary artery disease.
■ Increased in renal failure and secondary to some medications.
Human Chorionic Gonadotropin, Serum (HCG)
Nonpregnant state:  0.01 IU/mL
4 weeks pregnant: 0.10–1.0 IU/mL
16 weeks pregnant: 10–50 IU/mL
. Red-top tube.
■ Hormone produced by the placenta.
■ Levels peak at about 16 weeks and then decline.
Human Immunodeficiency Virus (HIV) Testing
HIV Antibody, ELISA: negative
HIV Western Blot: negative
HIV Antigen (P-24 Antigen): negative
HIV Viral  load: 50 copies/mL
. Red-top tube.
■ Used to diagnose HIV infection.
■ Viral load tests are used to inform treatment strategies and
monitor disease progression.
Human Leukocyte Antigens (HLA)
Match or nonmatch
. Green-top tube.
■ Used to assess tissue compatibility.
■ Useful in assessing compatibility for organ transplants.
5-Hydroxyindoleacetic Acid
2–8 mg/24 hr; SI units: 10.4–41.6 mmol/24 hr
. 24-hr urine collection.
■ Used in the diagnosis of carcinoid tumors (a tumor found in
the appendix or intestinal wall that secretes high levels of
serotonin leading to symptoms including hypertension,
facial flushing, abdominal cramps, and heart valve
■ Certain foods and medications must be avoided before
urine collection. These include: bananas, pineapple, red
plums, avocado, walnuts, kiwi, tomatoes, cough medicines,
muscle relaxants, acetaminophen, caffeine, fluorouacil,
iodine solutions, phenacetin, MAO inhibitors, isoniazid, and
phenothiazine drugs such as Compazine and Thorazine.
IgG (10 years old): 650–1700 mg/dL; SI units: 6.5–17 g/L
IgA (10 years old): 40–390 mg/dL; SI units: 0.40–3.90 g/L
IgM (2 years old): 25–210 mg/dL; SI units: 0.25–2.1 g/L
IgD: (Adults): 0.5–3 mg/dL; SI units: 0.005–0.03 g/L
IgE: (Adults): 0.01–0.04 mg/dL; SI units: 0–430 mg/L
. Red-top tube.
■ Used to evaluate immunity.
■ Monitor other diseases such as multiple myeloma,
lymphoma, bacterial infection, malnutrition, sarcoidosis.
International Normalized Ratio (INR)
See Prothrombin Time.
Iron Tests (Serum Iron, Total Iron Binding Capacity, Serum
Transferrin, Transferrin Saturation)
Serum Iron
Adult: 35–165 g/dL; SI units: 10–27 mol/L
Child 6 mo–2 yr: 40–100 g/dL; SI units: 7.16–17.9 mol/L
Total Iron Binding Capacity (TIBC)
250–460 g/dL; SI units: 45–82 mol/L
Serum Transferrin
200–430 mg/dL; SI units: 2–3.8 g/L
Transferrin Saturation
Male: 30–50%
Female: 20–35%
. Red-top tube.
■ Iron is critical to proliferation and maturation of red blood
■ 65% of iron is found in hemoglobin. Most of the rest is
stored as ferritin in in the liver, bone marrow, and spleen.
■ Transferrin is the major transporting protein of iron.
■ Increased in excessive iron intake and decreased
production of erthrocytes. Decreased in iron deficiency
anemia, normochromic anemia associated with chronic
17-Ketosteroids (17-Ketogenic Steroids, 17-KGS,
Adult: Male: 8–25 mg/24 hr; SI units: 27–85 mol/24 hr. Female:
5–15 mg/24 hr; SI units: 17–52 mol/24 hr.
Child: 1–3 mg/24 hr (age dependent; the younger the child, the
lower the normal range); SI units: 3–10 mol/24 hr.
. 24-hr urine collection.
■ Aids in the diagnosis of adrenal cortex dysfunction.
■ Increased in Cushing’s syndrome, stress, adrenocortical
cancer, testicular and ovarian cancers, infection, pituitary
■ Decreased in Addison’s disease, nephrosis, pituitary
Lactate Dehydrogenase (LD, LDH), LDH Isoenzymes
Adult: 100–190 U/L but may differ significantly from lab to lab
LDH Isoenzymes
LDH-1: 17–27%
LDH-2: 27–37%
LDH-3: 18–25%
LDH-4: 3–8%
LDH-5: 0–5%
. Red-top tube.
■ Enzyme present in many body tissues.
■ Elevated levels occur in many disease states including MI,
cancer, liver disease, muscle disease, and trauma.
Lactic Acid (Lactate)
Venous: 0.5–1.5 mEq/L or 8.1–15.3 mg/dL; SI units: 0.5–1.5 mmol/L
Arterial: 0.5–2 mEq/L or 11.3 mg/dL; SI units: 0.5–2 mmol/L
Critical Levels: (venous or arterial) 5 or 45 mg/dL; SI units:
5 mmol/L
. Green or gray-top tube. Send to lab on ice.
■ Sensitive indicator of tissue hypoxia.
■ Accumulation of excess lactic acid due to hypoxia coupled
with decreased hepatic clearance leads to lactic acidosis.
■ Lactic acid levels are increased in hemorrhage, shock, sepsis,
DKA, strenuous exercise, cirrhosis.
Adult: 0–25 g/dL; SI units: 0–1.2 mmol/L
Child: 10–20 g/dL; SI units: 0.48–0.966 mmol/L
Critical Levels: Adult: 40 g/dL; Child: 30 g/dL
. Lavender-, navy-, or green-top tube (check with lab).
■ Excessive lead accumulation results in neurologic impairment;
children are especially sensitive to lead poisoning.
■ Lethargy and coma are seen in adults with levels 60 mg/dL.
Legionnaire’s Antibody Test
. Red-top tube.
■ Requires two specimens; first is taken at acute onset and second
is taken at least 3 weeks later.
■ Considered diagnostic of Legionnaire’s disease (acute respiratory
infection with pneumonia) if the titer quadruples or if a single
titer is 1:256.
0–160 U/L; SI units: 0–160 U/L
. Red-top tube. Fasting sample.
■ Pancreatic enzyme elevated in acute pancreatitis.
See individual lipoproteins: Cholesterol, Triglycerides, and
Liver Function Tests (LFTs)
See individual tests for reference ranges.
. Red-top tube.
■ A panel of tests used to evaluate liver function. Includes:
◆ Alanine aminotransferase (ALT)
◆ Alkaline phosphatase (ALP)
◆ Aspartate aminotransferase (AST)
◆ Bilirubin
◆ Albumin
◆ Total protein
■ Used in the evaluation of symptoms associated with liver disease
(jaundice, nausea, vomiting and/or diarrhea; loss of appetite;
ascites, hematemesis, melena; fatigue or loss of stamina; history
of alcohol or drug abuse).
Low-density Lipoprotein (LDL)
See Cholesterol.
Luteinizing Hormone (LH)
Adult: Male: 7–24 IU/L; Females: 5–20 IU/L, with the midcycle
peak approximately three times the baseline level. (Reference
ranges vary with lab methodology.)
. Red- or lavender-top tube.
■ Ordered to evaluate fertility problems in men and women.
Lyme Disease Antibody
Negative/low titer (titer of 1:128 is borderline)
. Red-top tube.
■ A positive serology by ELISA is not definitive.
■ A Western blot can confirm the diagnosis of Lyme disease.
Lymphocyte Assay (CD4 marker, CD4/CD8 Ratio)
T cells: 60–80% or 600–2400 cells/L
B cells: 4–16% or 50–250 cells/L
CD4: 493–1191 L
CD8: 182–785 L; CD4/CD8 Ratio: 1
. Lavender-top tube.
■ Assessed in the diagnosis of AIDS, leukemias, lymphomas.
■ Used to guide drug therapy decisions in HIV infection and
■ See White Blood Cells and Complete Blood Count.
Magnesium, Serum
1.6–2.2 mg/dL; SI units: 0.66–0.91 mmol/L
Critical Levels: 1 or 5 mg/dL
. Red-top tube.
■ Electrolyte critical to many metabolic processes including
nerve impulse transmission, muscle relaxation,
carbohydrate metabolism, and electrolyte balance.
■ Low levels may cause cardiac irritability, weakness,
arrhythmias, seizures, and delirium.
■ Renal patients cannot excrete magnesium efficiently and
thus are at risk for hypermagnesemia.
1.5% of total hemoglobin. Levels 15% result in systemic
symptoms; levels 70% are fatal.
. Lavender- or green-top tube. Deliver to lab on ice.
■ Methemoglobinemia occurs when iron in hemoglobin is
oxidized to its ferric form. Methemoglobin binds so firmly with
oxygen that less of it is available to tissues. Excess levels
cause hypoxia.
■ Methemoglobinemia can be hereditary, but usually is acquired
from drugs and chemicals, such as nitrites and aniline
derivatives, which includes virtually all local anesthetics.
■ Excessive use of local anesthetics has caused fatal
Microalbumin (MA, Urine Albumin, Albumin
to Creatinine Ratio)
Microalbumin: 0–30 mg/day
Albumin to creatinine ratio: 0–-30 g albumin/mg creatinine; SI
units: 2.5 mg albumin/mmol creatinine
. 24-hr or timed urine specimen.
■ This test measures minute amounts of albumin in the urine
and is an early indicator of kidney damage, detecting kidney
damage up to 5 years earlier than routine urine protein tests.
■ Is used to identify diabetics at risk for nephropathy so that
appropriate intervention (ACE inhibitors to control
hypertension and tight glycemic control).
■ Levels 300 mg/day (SI units: 300 mg/L) indicate irreversible
■ The timed test (4-hr or overnight urine sample) is less
accurate than the 24-hr urine study. It uses a microalbumin to
creatinine ratio to correct for variations in urine dilution.
Myoglobin, Serum
90 g/L; SI units: 90 g/L
. Red-top tube.
■ Protein found in cardiac and skeletal muscle. Binds to oxygen
and provides a reserve of oxygen during exercise.
■ Rises in 3 hrs after cardic muscle damage and is therefore one
of the first markers to rise after an MI.
■ Ordered in conjunction with troponin.
Myoglobin, Urine
Random urine sample.
■ Myoglobin is released into the circulation, filtered by the
glomeruli, and excreted by the kidneys following muscle injury.
■ Elevations occur in skeletal muscle ischemia and trauma, MI,
muscular dystrophy, rhabdomyolysis, and malignant
. Red-top tube.
■ Indicator of liver damage secondary to biliary obstruction.
Osmolality, Serum
278–298 mOsm/kg H2O; SI units: 279–298 mmol/kg
Critical Levels: 265 or 320 mOsm/kg H2O
. Lavender- or green-top tube. Send to lab on ice.
■ Measures the concentration of particles in solution and therefore
indicates hydration status.
■ Osmolality increases with dehydration and decreases with fluid
Osmolality, Urine
24-hr urine: 300–900 mOsm/kg
Random sample: 50–1200 mOsmol/kg water
. Random, timed or 24-hr urine collection. Refrigerate specimen
during collection.
■ Osmolality is a measure of the number of particles in solution.
■ Used to assess electrolyte and fluid balance, the kidneys’ ability
to concentrate urine, renal disease, diabetes insipidus (DI), and
syndrome of inappropriate antidiuretic hormone secretion
■ Determination of both urine and serum osmolality aids in
interpretation of results.
Parathyroid Hormone (Parathormone, PTH)
10–55 pg/mL: SI units: 10–65 ng/L
. Red-top tube. Fasting specimen. Calcium level should be drawn at
the same time.
■ Secreted by the parathyroid gland; regulates calcium and
phosphorus. Useful for diagnosing parathyroid problems.
Partial Thromboplastin Time  (PTT)
20–35 sec
Critical Levels: 100 sec
. Blue-top tube.
■ Used to monitor therapeutic heparin, hirudin, or argatroban
■ Therapeutic levels of anticoagulant are indicated by PTT of
1.5– 2.5 times the control.
Parvovirus B19 Antibody
. Red-top tube.
■ Parvovirus B19 is responsible for fifth disease in children.
Infection is self-limited and does not require treatment.
■ Parvovirus infection can cause fetal harm, infectious arthritis
in adults, and severe anemia in immunocompromised
Phenylketonuria Test  (PKU Test, Guthrie Test)
Guthrie blood test: ≤ 2 mg/dL; SI units: ≤ 121 mol/L
PKU urine test: No green color.
. Heel stick to obtain a few drops of blood for filter paper or wet
diaper for test stick or ferric oxide test.
■ PKU is a heritable disease characterized by an inability of the
body to convert phenylalanine, present in protein foods, into
tyrosine. Excess phenylalanine results in mental retardation.
■ All states mandate testing of newborns.
■ Children with PKU must be maintained on a low-phenylalanine diet for 6–to 8 years.
Phosphorus, Serum (Phosphate, PO4)
Adult: 2.5–4.5 mEq/dL; SI units: 0.78–1.52 mmol/L
Child: 4.5–6.5 mg/dL; SI units: 1.45–2.1 mmol/L
Critical Levels: 1 mg/dL
. Red-top tube.
■ Phophorus is critical to cellular metabolism, cell membrane
integrity, and bone and teeth formation.
■ Increased in renal failure, hyperparathyroidism, diuretic abuse.
■ Decreased in hypoparathyroidism.
80–120% of normal for plasma
. Blue-top tube.
■ Plasminogen is the inactive precursor of plasmin. Plasmin
participates in fibrinolysis.
■ Used to evaluate hypercoaguable states such as thrombosis
and DIC.
Platelet Antibodies (Antiplatelet Antibodies)
. One red-top tube and one lavender-top tube.
■ Antibodies to platelets can result from an autoimmune
response or a reaction to transfused blood products.
■ The antibodies cause destruction of donor and native
■ Positive platelet antibodies are found in AIDS, acute myeloid
leukemia, immune complex diseases, drug-induced
thrombocytopenia, posttransfusion purpura, and idiopathic
thrombocytopenia purpura.
; SI units: 150–450  109
Critical Levels: 50,000 or 999,000/mm3
. Lavender-top tube.
■ Platelets are critical to hemostasis and blood clot formation.
■ The number of platelets may be normal but their function
impaired. Impaired platelet function is assessed by obtaining
bleeding times.
■ Increased platelets occur in many inflammatory disorders and
myeloproliferative states as well as in acute or chronic blood
loss, hemolytic anemias, after splenectomy, sudden exercise,
cirrhosis, and iron deficiency.
■ Thrombocytopenia (decreased platelets) occurs in aplastic
anemia, megaloblastic and severe iron deficiency anemias,
uremia, autoimmune thrombocytopenias, DIC, thrombotic
thrombocytopenic purpura, following massive hemorrhage, in
severe infection, and as a side effect of many different drugs
including: abciximab, alcohol, allopurinol, carbamazepine,
cimetidine, heparin, histamine blockers, most
chemotherapeutic agents, nonsteroidal anti-inflammatories,
procainamide, quinidine, quinine, ranitidine, rifampin.
Porphyrins, Urine
Total porphrins Male: 8–149 g/24 hr; Female: 3–78 g/24 hr
Uroporphyrin Male: 4–46 g/24 hr; Female: 3–22 g/24 hr
Coproporphyrin Male: 96 g/24 hr; Female: 60 g/24 hr
Porphobilinogen 0–2 mg/24 hr; SI units: 0.8–8.0 mol/day
. 24-hr or random urine. Keep refrigerated. Protect from light.
■ Porphyrins are important in the synthesis of heme.
■ Porphyrias are genetic enzyme deficiencies.
■ Lead poisoning is also associated with excess urine
Potassium, Serum (K 
Adult: 3.5–5.0 mEq/L: SI units: 3.5–5.0 mmol/L
Child: 3.4–4.7 mEq/L; SI units: 3.4–4.7 mmol/L
Critical Levels: 2.5 or 6.5 mEq/L
. Red-top tube.
■ Very narrow normal range; small changes in potassium
level can have profound effects on body functions.
■ Effects of potassium include transmission of nerve
impulses; contraction of skeletal, smooth, and cardiac
muscle; and maintenance of acid-base balance and
■ Potassium levels may be decreased secondary to vomiting,
diarrhea, diuretic use, insulin administration, burns, ascites,
and other clinical conditions.
■ Increased levels occur with excessive IV administration,
acute or chronic renal failure, potassium-sparing diuretics,
infection, dehydration, transfusion of hemolyzed blood.
20–40 mg/dL; SI units: 150–360 mg/L
. Red-top tube. Fasting sample.
■ Used to assess for malnutrition and to evaluate nutritional
status of hospitalized patients, patients scheduled for
surgery, and patients who are chronically ill.
■ Also used to monitor nutrition in patients receiving
parenteral nutrition or who are on hemodialysis.
Adult: Male:  0.3–1.2 ng/mL. Female: Follicular phase: 0.2–1.4
ng/mL; Luteal phase: 3.3–25.6 ng/mL; Midluteal phase: 4.4–28
ng/mL; 1st trimester: 11.2–90.0 ng/mL; 2nd trimester: 25.5–89.4
ng/mL; 3rd trimester: 48.4–422.5 ng/mL; Postmenopausal:
0–0.7 ng/mL
. Red-top tube.
■ Progesterone prepares the uterus for implantation of a
fertilized egg and may be used to confirm ovulation.
■ Increased in molar pregnancy, adrenal hyperplasia.
■ Decreased in placental deterioration, toxemia of pregnancy,
fetal death, ovarian cancer, threatened spontaneous abortion.
Prostate-Specific Antigen (PSA)
0–4 ng/mL; SI units: 4 g/L
. Red-top tube.
■ PSA is a glycoprotein made by cells in the prostatic ducts.
■ Test is used in the diagnosis and monitoring of prostate
■ Levels 10 ng/mL are associated with prostate cancer.
Protein Electrophoresis
Protein Type % of Total As g/dL
Albumin 58–74% 3.5–5.5 g/dL
Alpha-1 globulin 2.0–3.5% 0.2–0.4 g/dL
Alpha-2 globulin 5.4–10.6% 0.5–0.9 g/dL
Beta globulin 7–14% 0.6–1.1 g/dL
Gamma globulin 8–18% 0.7–1.7 g/dL
. Red-top tube. May require random or 24-hr urine as well.
■ Protein electrophoresis is a method for separating the proteins
found in serum or urine. The proteins form a specific pattern
in the electrical field. The pattern is then interpreted.
■ Used to identify abnormal proteins and to detect monoclonal
proteins (the abnormal production of one immunoglobulin).
■ Ordered when multiple myeloma is suspected, when total
protein or albumin levels are abnormal, or when urine protein
levels are elevated.
Protein, Urine
30–140 mg/24 hr; SI units: 0.01–0.14 g/24 hr
. Random or 24-hr urine collection. Refrigerate during collection.
■ Urine normally contains only scant quantities of urine.
■ Used to assess renal function, preeclampsia, multiple
■ See Bence Jones Protein.
Prothrombin Time (PT); International Normalized Ratio (INR)
Prothrombin time
10–14 sec
Critical Levels: 30 sec
2–3 for patients with PE, DVT, valvular heart disease; 2.5–3.5 for
patients with prosthetic heart valve or recurrent systemic
. Blue-top tube.
■ The PT is the amount of time it takes blood to clot when mixed
with a thromboplastin reagent. Normal values vary widely with
different thromboplastin reagents. The INR uses a conversion
factor that accounts for the differences in reagents. This allows
the health care provider to evaluate and compare test results
regardless of the reagents used by different laboratories.
■ Used primarily to evaluate warfarin therapy.
■ Therapeutic levels of warfarin are indicated by a PT one and a
half to two times times the control.
Renin (Plasma Renin Activity)
Adult: Normal sodium diet, upright: 1–6 ng/mL/hr; SI units: 0.77–4.6
mmol/L/hr. Sodium-restricted diet, upright: 0.1–3.0 ng/mL/hr
. Lavender top-tube. Note position of patient (supine or upright)
and normal or sodium-restricted diet.
■ Used in the diagnosis and treatment of hypertension.
Reticulocyte Count
Adult: 0.5–1.5% of all RBCs
Child:0.5–2.0% of all RBCs
. Lavender top tube.
■ Reticulocytes are juvenile RBCs.
■ Used in to evaluate the etiology of anemia, erythropoietin
therapy, and recovery from myelosuppression.
Rheumatoid Factor (RF)
1:20 titer (agglutination method)
. Red-top tube.
■ Used in the diagnosis of rheumatoid arthritis.
■ RF is an antibody that attaches to immunoglobulin G (IgG).
■ Also elevated in collagen vascular diseases, infections, cancer,
and MI.
Rotavirus Antigen
. Small amount of stool in a sterile container. Refrigerate
immediately after collection.
■ Common cause of diarrhea in infants and young children.
■ Highly contagious; transmitted by the fecal-oral route.
SARS CoV, Serum
Negative coronavirus antibodies
. Gold-top tube.
■ Specimens should be collected when the diagnosis is first
suspected and at later times if indicated.
■ An antibody response may be detected during the first week
of illness, but a response is more likely by the end of the
second week up to 28 or more days after onset of symptoms.
Sedimentation Rate (Erythrocyte Sedimentation Rate, ESR)
Adults (Westergren method): Males under 50 yr: 15 mm/hr. Males:
over 50 yr: 20 mm/hr. Females under 50 yr: 20 mm/hr; Females
over 50 yr: 30 mm/hr.
Children (Westergren method): Newborn: 0 to 2 mm/hr; 6 mo–to 12
yr: 3–13 mm/hr.
. Lavender-top tube.
■ Measures the rate at which red blood cells settle in saline or
plasma at the bottom of a test tube. In certain disease states
(inflammation, infection, cancer), erythrocytes stack together,
increasing their weight and the rate at which they settle. Thus,
increased sedimentation rate is an indicator of these
■ Used to monitor inflammatory or malignant disease,
rheumatic fever, and heart attack.
■ Useful in monitoring tuberculosis, tissue necrosis,
rheumatologic disorders, and other diseases.
Sickle Cell Screening Test
See Hemoglobin Electrophoresis.
Sodium, Serum
136–145 mEq/L; SI units: 136–145 mmol/L
Critical Levels: 120 or 160 mEq/L
. Red- or green-top tube.
■ Sodium is critical to body water distribution, maintenance
of osmotic pressure, neuromuscular function, acid-base
balance, and electrolyte balance.
■ Decreased in many clinical conditions including diarrhea,
vomiting, nasogastric suction, SIADH, diuretics, and
congestive heart failure.
■ Increased in excessive dietary or IV intake, Cushing’s
syndrome, diabetes insipidus, and excessive sweating.
Sodium, Urine
See Electrolytes, urine.
Sputum Culture and Sensitivity (Sputum C&S and Gram stain)
Normal flora
. Sputum specimen in sterile container.
■ To identify pathogenic organisms in the respiratory tract.
■ Discard specimens that are mostly saliva; obtain specimen
from from the bronchi after instructing the patient to cough
■ Some patients may require suctioning to obtain an
appropriate sputum sample.
Stool Culture (Stool for C&S, Stool for Ova
and Parasites [O&P])
Normal intestinal flora
. Small amount of stool specimen in a sterile container with a
screw-top lid.
■ Evaluate cause of diarrhea.
Sweat Electrolytes
Normal: 70 mEq/L; Abnormal: 90 mEq/L; Equivocal: 70–90 mEq/L
Normal: 50 mEq/L; Abnormal: 60 mEq/L; Equivocal: 50–60 mEq/L
. Collection of sweat on filter paper after iontophoresis (stimulation
of sweating with pilocarpine).
■ Screening or diagnostic test for cystic fibrosis (CF).
■ Children with CF have increased sodium and chloride in their
T3 Radioimmunoassay (Triiodothyronine)
75 to 220 ng/dL; SI units: 1.2–3.4 nmol/L
. Red-top tube.
■ Major hormone produced by the thyroid gland.
■ Used primarily to aid in the diagnosis of hyperthyroidism.
T3 Resin Uptake (T3RU, RT3U, Resin T3 Uptake)
. Red-top tube.
■ Part of the thyroid function tests.
■ Measures the percentage of thyroid hormone bound to protein
and therefore indicates the percentage of binding sites
■ T3 uptake 37% indicates number of available binding sites is
low, which occurs in hyperthyroidism.
■ T3 uptake 37% indicates number of available binding sites is
high, which occurs in hypothyroidism.
T4,Total (Thyroxine Screen)
Adults: 4.5 to 11.2 g/dL; SI units: 58–154 nmol/L
Infant (1 wk–4 mo): 9–16 g/dL
Critical Levels: Adults: 18 g/dL; Infant: 3.5 or 18.0 g/dL
. Red-top tube.
■ Major hormone produced by the thyroid gland. Controls basal
metabolic rate.
■ Used to screen for/diagnose hypothyroidism or
■ Total T4 measure all the T4 both protein bound (96–99%) and
free (1–4%).
T4,Free (Free Thyroxine)
Adult: 0.8–2.8 ng/dL; SI units: 10–36 pmol/L
Neonate (to 4 days old): 2–6 ng/dL; SI units: 26–77 pmol/L
Child 2 wk–20 yr: 0.8–2.0 ng/dL
. Red-top tube.
■ Total T4 levels can be affected by protein levels in the blood
and therefore give false results.
■ Free or unbound T4 is measured in patients with protein
abnormalities to get a more accurate indicator of thyroid
Adult: Male: 300–1100 ng/dL; SI units: 9.71–38.14 nmol/L. Female:
15–70 ng/dL; SI units: 0.52–2.43 nmol/L
Child (10–11 yr old): Male: 5–50 ng/dL. SI units: 0.17–1.73 nmol/L.
Female: 5–25 ng/dL; SI units: 0.17–0.87 nmol/L
. Red- or green-top tube.
■ Used to assess early or late puberty in boys and for evaluation
of impotence and infertility in men.
■ Used in the evaluation of excess hair growth, virilization (male
body characteristics) and irregular menses in women.
Throat and Nares Culture
Normal flora
. Collect specimen in commercial culture swab.
■ Identify pathogenic organisms from oropharynx and evaluate
nares for staph colonization.
■ To obtain throat culture, swab vigorously over both tonsils
and the posterior pharynx avoiding the tongue and uvula.
■ For nares, insert swab into nostril until it touches the posterior
nares. Leave swab in place for 15 sec, rotate, and remove.
■ Neisseria gonorrhoeae and C. diptheriae require special media.
Thyroid Function Tests
See individual tests for reference ranges.
. Red-top tube.
■ The thyroid gland produces three hormones: thyroxine (T4),
triiodothyronine (T3) and calcitonin. T3 and T4 are collectively
referred to as thyroid hormone.
■ Thyoid hormone controls cellular metabolic activity and is
critical to brain development and growth.
■ Thyroid hormone secretion is controlled by TSH (thyroid-stimulating hormone) from the anterior pituitary gland.
■ Laboratory thyroid function tests include TSH, T3, T4, Free
Thyroxine, T3 Resin Uptake, and Thyroid Antibodies.
Thyroid Antibodies (Antithyroglobulin Antibody and
Antimicrosomal Antibody)
. Red-top tube.
■ Confirm the cause of thyroid dysfunction.
■ Microsomal antibodies are produced in response to
microsomes released from damaged thyroid cells.
Thyroid-stimulating Hormone (TSH)
0.4–4.2 U/mL: SI units: 0.4–4.2 mU/L
Neonates: 20 U/mL: SI units: 20 mU/L
. Red-top tube.
■ Best screening test for thyroid function.
■ Increased levels indicate hypothyroidism; decreased levels
indicate hyperthyroidism.
■ Also used to monitor thyroid hormone replacement therapy.
TORCH Screen (Toxoplasmosis, Rubella, Cytomegalovirus,
Herpes Viruses)
. Red-top tube.
■ Detect maternal and infant infection.
■ High levels of immunoglobulin IgM against any of the
microorganisms indicates congenital infection.
Adult: 220–430 mg/dL: SI units: 2.2–4.3 g/L
Newborn: 125–175 mg/dL: SI units: 1.25–2.75 g/L
. Red-top tube. Fasting sample.
■ Transferrin transports circulating iron to bone marrow for
hemoglobin synthesis or to the liver, spleen, and bone
marrow for storage.
■ Increased in iron deficiency anemia.
■ Decreased in liver damage, malnutrition, renal disease, and
Adult: 150 mg/dL; SI units: 1.7 mmol/L
Child (over 10 yr): Male: 32–148 mg/dL: SI units: 0.36–1.67
mmol/L. Female: 37–124 mg/dL: SI units: 0.42–1.4 mmol/L
. Red-top tube. Fasting sample.
■ Triglycerides are fats and are assessed as part of a lipid
■ Levels 1000 mg/dL are associated with pancreatitis.
Troponins (TnI, TnT)
Cardiac troponin T: 0.2 ng/mL
Cardiac troponin I: 0.03 ng/mL
. Yellow-top tube.
■ Proteins that help regulate cardiac contractility.
■ Sensitive biomarker of cardiac muscle injury.
■ Toponins become elevated earlier and remain elevated
longer than CPK-MB, which allows for earlier diagnosis and
initiation of thrombolytic therapy.
Tuberculosis Culture (TB Culture, AFB Smear)
No acid-fast bacilli observed on smear or isolated in culture.
. Sealed or screw-topped container for all specimen types
(sputum, urine, other body tissue or fluid). Urine and sputum
cultures are collected serially (usually for 3 days). Sputum
specimen should be obtained in the early morning; induced
sputum may be required if specimen is inadequate. Send to
lab immediately.
■ Tuberculosis is diagnosed by culturing Mycobacterium
tuberculosis from a specimen.
■ AFB smear (smear for acid-fast bacilli) is performed in
addition to the culture. A second specimen may be required
for the AFB smear if the volume of specimen is in adequate.
AFB is used to monitor therapy effectiveness.
■ Antibiotic sensitivity may be performed as well.
Tumor Necrosis Factor-a (TNF-a, Cachectin)
8.1 pg/mL
. Red-top tube
■ TNF-a is cytokine (an immune system protein) involved in
systemic inflammatory processes.
■ Inhibition of TNF-a is part of the treatment strategy for
autoimmune diseases such as rheumatoid arthritis.
■ Elevated in sepsis, autoimmune diseases, infectious
diseases, and transplant rejection.
Uric Acid, Serum
Adult: Male: 4.0–8.5 mg/dL; SI units: 0.24–0.51 mmol/L. Female:
2.8–7.3 mg/dL; SI units: 0.16–0.43 mmol/L
Child: 2.5–5.5 mg/dL; SI units: 0.12–0.32 mmol/L
Critical Levels: 12 mg/dL
. Red-top tube.
■ Uric acid is the end product of purine metabolism.
■ Useful to assess for gout and to monitor patients with renal
failure or to monitor if uric acid levels are too high after
chemotherapy or radiation.
Uric Acid, Urine
Low purine diet: 250–500 mg/day; Unrestricted diet: 250–750
. 24-hr urine. Refrigerate during collection.
■ Assess for elevated levels of urine uric acid in patients with
renal calculus formation or identify patients at risk for stone
■ Uric acid kidney stones occur in gout or secondary to
malignant diseases, ulcerative colitis, Crohn’s disease, and
surgical jejunoileal bypass.
Urinalysis (UA)
Characteristic Normal Finding
Appearance and color  Clear; yellow, straw
pH 4.6–8.0
Protein 2–8 mg/dL
Specific gravity 1.005–1.030
Leukocyte esterase Negative
Nitrite Negative
Glucose Negative
Ketones Negative
White blood cells 3–4
White blood cell casts Negative
Red blood cells 1–2
Red blood cell casts Negative
Crystals Few/Negative
. Random urine sample.
■ Urinalysis provides information about the renal/urinary
■ Protein content in urine is indicative of decreased renal
■ Specific gravity measures the concentration of particles in the
urine and is an indicator of the kidney’s ability to concentrate
urine. It also reflects overall hydration status. Low specific
gravity indicates that the urine is dilute; high specific gravity
means that the urine is concentrated (volume depletion).
■ Leukocyte esterase, nitrite, and white blood cells in the urine
are an indication of urinary tract infection.
■ Red blood cells indicate of damage to the renal tubules.
■ Crystals indicate the presence of renal stones.
■ Casts are clumps of cells formed in the tubules. Hyaline casts
indicate protein in the urine. WBC and RBC casts are generally
indicative of upper urinary tract infection. RBC casts are also
present in other serious kidney disorders. Renal tubular
epithelial cell casts reflect damage to the tubules and are
found in renal tubular necrosis, viral disease, and transplant
Urine Culture and Sensitivity (Urine C&S)
Negative or No Growth
. Clean catch mid-stream urine sample, or aseptic aspiration of
urine from a closed urinary drainage system, in a sterile
■ Test for pathogenic bacteria in patients with suspected UTI or
abnormal urinalysis results (positive leukocyte esterase,
increased number of WBC in urine, bacteria in urine).
■ Test includes determining to which antibiotics the bacteria are
■ Bacterial counts 100,000/mL of a single organism indicate a
0–4 mg/24hr; SI units: 0.09–4.23 mol/24 hr
. 24-hour urine collection.
■ An increase in urobilinogen indicates hepatocellular dysfunc-tion or an increased bilirubin production due to hemolysis.
■ Absence of urobilinogen indicates complete biliary obstruction.
VDRL (Venereal Diagnosis Research Laboratory, Rapid Plasma
Reagin, RPR)
. Red-top tube.
■ Used to diagnose syphilis infection.
■ Blood test detects antibodies to Treponema pallidum;
therefore indicates current or past infection.
■ Lumbar puncture and CSF analysis are necessary to detect
Viral Culture
. Lavender-top tube for blood; other specimens (cerebrospinal
fluid; dermal, ocular, genital, mucosal, oral, or rectal lesions;
respiratory washings; stool, tissue, urine, or biopsy specimens)
sent in sterile container, viral culturette swab, or lab-provided
medium). Transport specimens immediately or refrigerate.
■ Assess body tissue for adenovirus, cytomegalovirus,
enteroviruses, herpes simplex virus, influenza, mumps,
parainfluenza, RSV, etc.
Viral Load (Plasma Viral Load, PVL)
Results range from No Detectable Virus and Low Levels (200–500
copies/mL) to High Levels (10,000 copies/mL )
. Lavender-top tube.
■ Indicates the amount of HIV-RNA present in the blood.
■ Used to monitor the status of HIV disease and inform
therapy changes.
■ Tests are performed serially with treatment changes to
monitor treatment response.
Vitamin B12
160–900 pg/mL; SI units: 118–690 pmol/L
. Red-top tube.
■ B12 is essential to the proper formation and function of
■ B12 deficiency can result from insufficient intake of foods
containing B12; malabsorption from celiac disease, reduced
stomach acid, lack of intrinsic factor (pernicious anemia) or
surgical resection of the stomach or small intestine; liver
and kidney diseases, alcoholism, and certain medications.
■ Ordered to establish cause of macrocytic anemia.
West Nile Virus
. Red-top tube.
■ Involves testing for IgM and IgG West Nile virus (WNV)
antibodies or testing for WNV genetic material.
■ Indicates current or recent infection.
■ May be assessed repeatedly to determine if antibody levels
are stable, rising, or falling.
White Blood Cell Count and Differential
Absolute (Percentage) SI Units
Total WBC
Total Neutrophils
◆ Neutrophils,
◆ Neutrophils,
◆ T cells
◆ B cells
. Lavender-top tube.
■ White blood cells are crucial to defending the body from
foreign organisms, tissues, and other substances.
■ An elevated white blood cell count (leukocytosis) usually
represents an increase in one of the types of WBCs rather than
an increase in all the types of cells.
■ An increased lymphocyte count is seen in infectious
mononucleosis, viral hepatitis, cytomegalovirus infection,
other viral infections, pertussis, toxoplasmosis, brucellosis, TB,
syphilis, lymphocytic leukemias, chronic bacterial infection,
and multiple myeloma.
◆ An increased neutrophil count may indicate acute infection,
eclampsia, gout, myelocytic leukemia, rheumatoid arthritis,
rheumatic fever, acute stress, thyroiditis, trauma.
• “Left shift” occurs when there is more than 10–12%
bands or when the sum of bands plus segmented
neutrophils is 80%.
• The left shift represents an increase in the percentage of
immature band neutrophils to mature segmented
neutrophils and occurs in bacterial infection and toxemia
but can also occur in acute stress situations.
2500–8000 (55–70%)
0–700 (0–5%)
1800–7000 (54–65%)
1000–4000 (25–40%)
600–2400 cells/L
50–250 cell/L
100–700 (2–8%)
50–500 (1–4%)
25–100 (0–1%)
4.3–10.8  109
2.5–80  109
0.03–0.08  109
0.54–0.65  109
0.25–0.40  109
600–2400 cells/L
50–250 cell/L
0.02–0.08  109
0.01–0.04  109
0–0.01  109
•T cells, specifically CD-4 T  cells are monitored in
patients who are HIV positive.
◆ An increased eosinophil count occurs in allergic
disorders, parasitic infection,and Hodgkin’s disease.
◆ An increased monocyte count may indicate chronic
inflammatory disease, parasitic infection, tuberculosis,
and viral infection.
■ Decreased white blood cell count is called leukopenia.
◆ Decreased lymphocytes is the hallmark of AIDS. It also
occurs in acute infections, Hodgkin’s disease, leukemia,
sepsis, systemic lupus, renal failure, and radiation
◆ Decreased neutrophils may occur in aplastic anemia,
influenza, chemotherapy, overwhelming bacterial
infection, and secondary to medications including:
•Analgesics and anti-inflammatories
• Antibiotics
• Anticonvulsants
• Antimetabolites
• Antithyroid drugs
• Arsenicals
• Barbiturates
• Cardiovascular drugs
• Diuretics
Wound Culture
No growth, routine or normal skin flora, routine or normal flora
for body area cultured.
. Collect exudate or tissue sample in a sterile specimen cup
(with screw-top lid) or swab in culture tube. Aspirated exudate
may be sent to lab in syringe with needle removed. Source of
specimen must be identified.
■ To identify pathogenic organisms in wounds.
■ Common organisms cultured from wounds include
Escherichia coli, Proteus, Klebsiella, Pseudomonas,
Enterobacter, enterococci, other streptococci, Bacteroides,
Prevotella, Clostridium, Staphylococcus aureus, and
coagulase-negative Staphylococcus.
Xylose Tolerance  test
2 hr (plasma) 5 hr (urine)
Adult 32–58 mg/dL 4 g/5 hr (16–32%)
. Gray-top tube; fasting sample and sample 2 hr after ingestion
of xylose. Plastic urine container for urine sample.
■ After ingestion, xylose is absorbed by the small bowel and
30– 40% excreted in the urine. Intestinal malabsorption is
indicated by low blood levels and decreased urine
■ Decreased levels seen in celiac diseases, tropical sprue,
Crohn’s disease, immunoglobulin deficiency, pellagra,
radiation enteritis, surgical bowel resection, vomiting,
delayed gastric emptying, thyroid disease, ascites, and
increased intestinal motility.
60–130 mg/dL; SI units: 9–20 mmol/L
. Royal blue–top tube.
■ Zinc contributes to RNA and DNA synthesis and is essential
to tissue repair.
■ Used to evaluate suspected nutritional deficiency, especially
for burn patients and patients receiving enteral or parental
■ Useful in evaluating patients with delayed wound healing
or growth retardation.
General Description and Process
■ X-rays are used to evaluate the structure of bones and soft
■ X-rays are similar to visible light, but have a shorter
■ The patient is placed between x-ray machine and specially
treated film.
■ Gamma rays created in the x-ray machine pass through the
patient’s body.
■ Different internal structures absorb the x-rays in varying
amounts, which results in shadows of varying shades of gray
being cast on the film.
■ The amount of x-rays absorbed and therefore the image on
the film varies according to the composition and density of
tissues. The greater the density, the more radiopaque the
image; the lesser the density, the more radiolucent the image.
◆ Dense structures such as bone absorb most of the x-rays
and appear white on film.
◆ Air-filled structures do not absorb x-rays and appear black.
◆ Fat, muscle, and fluids appear as shades of gray.
■ Images may be enhanced with contrast medium.
Air appears black and is the most radiolucent
Fat appears very dark gray
Water appears medium gray
Bone appears light medium gray
Contrast appears very light gray
Heavy metals (foreign objects, joint prostheses)
appear white and are the most radiopaque
Te r m s
Attenuation: process by which radiation loses power as it travels
through body tissues and interacts with them. Attenuation
creates the contrast observed in x-ray images.
Contrast: the difference in brightness between the light and dark
areas of a picture or image.
Contrast-mediated x-rays: radiologic studies of soft tissues in
which contrast media have been used to enhance the structural
details visible on film.
Contrast medium: substance that alters the contrast by
increasing or decreasing attenuation. Barium sulfate and iodine
are the most commonly used contrast media.
Fluoroscopy: x-rays are passed through the patient to a viewing
screen so that movement of structures can be observed.
Plain x-rays: radiologic studies performed without contrast media
or other supplemental technique. Used for bones or air-filled
structures (e.g., chest, abdomen).
Tomography: radiographic imaging technique in which the x-ray
source and the film are moved in opposite directions. This
results in a two- dimensional image of a specific plane. (See CT
Xeroradiography: technique that uses a photoelectrical process
similar to photocopying. Useful for soft tissue imaging such as
Basic Positions for X-rays
AP (anterior-posterior): X-ray passes through patient from front
to back.
PA (posterior-anterior): X-ray passes through patient from back to
Lateral: Patient is positioned on either side and so that the x-ray
passes from one side of body through the other.
Oblique: X-ray is angled between PA and lateral positions.
(see Figures)
Anterior-Posterior Position (AP)
Anterior-posterior position.
Posterior-Anterior Position
Posterior-anterior position.
Lateral Positions
Right lateral position.
Left lateral position.
Posterior Oblique Positions
Right posterior oblique position.
Left posterior oblique position.
Anterior Oblique Positions
Right anterior oblique position.
Left anterior oblique position.
General Patient Preparation for Plain X-rays
■ Determine if the patient is pregnant or may be pregnant. X-ray is
contraindicated unless benefit to mother outweighs risk to fetus.
■ The reproductive organs are shielded during x-ray unless
abdominal films are needed on a female.
■ If scheduled for abdominal films, determine if the patient has
had a barium contrast study or taken medications containing
bismuth in the previous 4 days. (Films will need to be postponed
until all contrast is excreted.)
■ Tell the patient that he or she will have to stay very still while
films are being taken (approximately 1 sec for each view).
■ Remove metal objects and jewelry. If jewelry has psychological
or spiritual significance for the patient, it can usually be held by
the patient or moved to a part the body not under examination.
Abdominal X-ray
Plain film of the abdomen; also called abdominal flat plate or KUB
for kidneys, ureter, and bladder.
■ Assess cause of abdominal pain.
■ Evaluate liver or kidney size, shape, and position.
Patient lies supine on the x-ray table. Males will have the testicles
shielded. One AP (anterior-posterior) image is taken unless
abdominal x-ray is part of an Obstruction Series.
■ See General Pretest Patient Education in Tools Tab.
■ Tell patient that he or she will have to take a deep breath and
hold it or exhale and not breathe for 2 or 3 sec while pictures are
■ Tell patient not to expect discomfort during test.
■ No special posttest care required.
Bone Densitometry (Bone Mineral Density,
Uses an enhanced type of x-ray technology called dual-energy x-ray
absorptiometry to measure bone density. A portable DEXA device
can be used to measure bone density in the wrist, heel, or fingers.
The larger device, available in hospitals, usually assesses density
of the lower spine or hip. Although DEXA is the most widely used
scan, other methods for assessing bone density, including
ultrasound and computed tomography, are also available.
■ Identify risk for osteoporosis.
■ Monitor rate of bone loss in patients with osteoporosis.
The patient lies on a padded table. The x-ray generator is below the
table and the detector is above. A narrow beam of low-dose x-rays
from below the padded table passes through the bone while an
arm above the table scans the body, detecting the x-ray beam.
Software interprets the data, providing both an image of the bone
and an analysis the density of the bone matrix.
Test results are reported in terms of standard deviations from the
norm. A score of greater than -1 is considered normal. A score
between -1 and -2.5 is classified as osteopenia, the first stage of
bone loss. A score of less than -2.5 indicates osteoporosis.
■ See General Pretest Patient Education in Tools Tab.
■ The patient will have to remove jewelry if it is in the x-ray field. If
jewelry has psychologic or spiritual significance, the patient may
hold the jewelry during the procedure.
■ Although x-rays are not painful, some patients may experience
discomfort related to repositioning.
■ The patient will have to stay still during the test.
■ No special posttest care required.
Bone X-rays (Clavicle, Scapula, Foot, Hand, Toe,
Finger, Mandible)
Plain films of bones or joints including the clavicle, scapula, foot, hand,
finger, toe, and mandible. See Long Bone X-rays.
■ Assess for fracture, tumor, infection, structural abnormalities,
degenerative diseases.
■ Evaluate pain, loss of function, deformity.
The patient may stand or sit, or lie on the x-ray table depending upon the
anatomic part being studied.
■ See General Pretest Patient Education in Tools Tab.
■ The patient will have to remove jewelry if it is in the x-ray field. If
jewelry has psychologic or spiritual significance, the patient may hold
the jewelry during the procedure.
■ Although x-rays are not painful, some patients may experience
discomfort related to repositioning.
■ No special posttest care required.
Plain film of hand showing metacarpal fracture
Chest X-ray
Plain film of the chest. Different possible views include:
◆ PA (posterior-anterior): diminishes image of heart making
other structures clearer.
◆ AP (anterior-posterior): enhances cardiac image.
◆ Lateral: heart is less magnified.
◆ Oblique: aids in evaluation of lung masses and infiltrates.
◆ Lateral decubitus (cross-table lateral): used when fluid in chest
cavity is suspected.
■ Assess lung fields, cardiac border, large arteries, clavicle, ribs,
diaphragm, and mediastinum.
■ Diagnose pulmonary or cardiac disorders including heart
failure, COPD, pneumonia, TB, and neoplastic disease.
■ Evaluate placement of feeding tubes, chest tubes, central
venous catheters, pacemaker wires, endotracheal tubes, etc.
Patient stands or is placed in appropriate position. Reproductive
organs and thyroid gland may be shielded. Images are taken,
frequently PA and lateral.
■ See General Pretest Patient Education in Tools Tab.
■ Tell patient that he or she will have to take a deep breath and
hold it for 2 or 3 sec while pictures are taken.
■ Tell patient that metal necklaces will need to be removed. If
jewelry has psychologic or spiritual significance, the patient
may hold the jewelry during the procedure.
■ Tell patient not to expect discomfort during test.
No special posttest care required.
Chest X-ray with Anatomic Landmarks
Chest x-ray showing anatomic sructures.
Abnormal Chest X-ray
Abnormal densities of lung cancer.
air bubble
vena cava
Joint X-rays
Plain films of a joint or joints (hip, knee, shoulder, elbow, ankle, wrist,
joints in the feet and hands, etc).
■ Assess for fracture, infection, cysts, tumor, degenerative diseases.
The patient lies on the x-ray table while various views of the joint are
■ See General Pretest Patient Education in Tools Tab.
■ The patient will have to remove jewelry if in the x-ray field.
■ Although the x-ray is not painful, some patients may experience dis-comfort when painful joints are manipulated and repositioned for x-ray.
■ No special posttest care required.
Long Bone X-rays
Plain film of a long bone such as the femur, tibia/fibula, humerus, or
■ Evaluate bone pain or assess for fracture, tumor, infection, joint or
bone deformity.
Patient may lie on the x-ray table or sit depending on extremity to be
filmed. Several views may be taken.
■ See General Pretest Patient Education in Tools Tab.
■ Although the x-ray is not painful, some patients may experience
discomfort from having an injured or painful extremity positioned for
■ No special posttest care required.
X-ray (xeroradiography) of the breasts.
■ Detect tumors, cysts, and other breast disorders.
■ Differentiate between malignant and benign lesions.
The patient either sits or stands in front of the x-ray machine.
One breast at a time is rested on a flat surface that contains the x-ray
plate. A compressor firmly presses against the breast to flatten the tissue.
X-ray films are taken from several angles while the patient holds her
■ Remove metal objects and jewelry from around the neck or chest. If
jewelry has psychologic or spiritual significance for the patient, it can
be held by the patient or moved to a part the body not under
■ Tell the patient not to wear talcum powder or deodorant the day of test.
■ Explain that some patients experience brief discomfort from breast
compression and that the test takes 15 min.
■ No special posttest care is required.
Mammogram showing breast cancer
Obstruction Series
Plain film of the abdomen plus abdominal films in other positions.
■ Assess for bowel obstruction, paralytic ileus, bowel perforation.
Patient stands erect and lies supine while abdominal films are taken.
Other views may include cross-lateral (lateral decubitus) and lower
■ See General Pretest Patient Education in Tools Tab.
■ Tell patient that he or she will have to take a deep breath and hold it or
exhale and not breathe for 2 or 3 sec while pictures are taken.
■ Tell patient not to expect discomfort during test.
■ No special posttest care required.
Orbital X-rays
Plain film of the orbits of the eyes.
■ Assess for fracture, foreign body, tumor, congenital abnormality.
Patient may lie on the table or sit in a chair. Several views may be taken
with the head immobilized by sand bags or foam pads.
■ See General Pretest Patient Education in Tools Tab.
■ The patient will have to remove jewelry from the head and neck and
■ Although the x-ray is not painful, some patients may experience
discomfort if recent history of head or neck trauma.
■ No special posttest care required.
Paranasal Sinuses X-rays
Plain films of facial sinuses.
■ Assess for fracture, infection, cysts, tumor, foreign body.
Patient sits in an x-ray chair. The patient’s head is placed in a padded
brace for proper immobilization. Several views may be taken.
■ See General Pretest Patient Education in Tools Tab.
■ The patient will have to remove jewelry from the head and neck
and dentures.
■ Although the x-ray is not painful, some patients may experience
discomfort if recent history of head or neck trauma.
No special posttest care required.
Skull X-rays
Plain film of cranial vault, facial bones.
■ Assess for fracture, infection, tumor.
Patient may lie on the x-ray table or sit in a chair. Several views are
taken, which require the patient to assume different positions and
may require varying degrees of neck flexion. The head will be
immobilized with sand bags or foam pads.
■ See General Pretest Patient Education in Tools Tab.
■ The patient will have to remove jewelry from the head and neck,
and dentures.
■ Although the x-ray is not painful, some patients may experience
discomfort if recent history of head or neck trauma.
■ No special posttest care required.
Spinal X-rays
Plain films of the cervical, thoracic, lumbar, sacral or cocygeal spine.
■ Assess back and neck pain, assess for fracture, tumor, spinal alignment
abnormalities, degenerative diseases.
The patient lies on the x-ray table while various views of the spine are
■ See General Pretest Patient Education in Tools Tab.
■ The patient will have to remove jewelry if it is in the x-ray field. If
jewelry has psychological or spiritual significance, the patient may hold
the jewelry during the procedure.
■ Although the x-ray is not painful, some patients may experience
discomfort related to repositioning for x-ray.
■ No special posttest care required.
Degenerative disc disease of the cervical spine. Decreased disc space at C5–6 with
osteophyte formation anteriorly (white arrow) and posteriorly (black arrow).
Contrast Agents
Contrast agents enhance visualization of structures that do not
show up well on x-ray alone. They do this by blocking the passage
of x-rays, which causes the structures to appear white on the film.
The most commonly used contrast media contain barium (for
gastrointestinal studies) or iodine (for other studies). Contrast
agents containing iodine are referred to as iodinated contrast
media (ICM) and are capable of causing severe adverse reactions.
Iodinated contrast media are categorized as ionic or nonionic and
high osmolality or low osmolality. Ionic contrast media dissolve
into charged particles in the bloodsteam. They are associated with
a higher incidence of adverse reations because the charged
particles can disrupt cardiac and neural electrical activity. Nonionic
contrast agents do not dissolve into charged particles and are
considered safer. Osmolality is the concentration of particles or
molecules of solids dissolved or suspended in solvent or liquid. A
contrast with a high osmolality has a higher number of particles in
solution and is associated with adverse reactions (see section on
Osmolality below).
Mild adverse reactions (see Table) are not uncommon; severe
reactions are rare but potentially life-threatening. Reactions are
more common when contrast is administered IV.
Because of the risk of adverse reaction, informed consent is
required when an iodinated contrast medium is used.
Osmolality and Adverse Reactions
Although adverse reactions often look like an allergic response, the
effects are related to the osmolality of the injected substance
rather than an allergy to iodine.
◆ Introduction of highly osmolar fluids into the bloodstream
causes fluid shifts resulting in fluid overload and compensatory
blood vessel dilation, which causes cardiovascular effects (see
◆ Vasonconstricting substances are released into the system as a
result of the arterial dilation. This can result in diminished blood
supply to the kidneys and kidney damage.
◆ Homeostasis will be disrupted less if the contrast agent has an
osmolality similar to that of blood plasma, which is 300 osmol/kg.
◆ Low-osmolarity contrast has an average osmolality of 750 osmol/
kg or less, whereas high-osmolarity contrast has an osmolality of
1000–2400 osmol/kg.
◆ Anaphylactoid reactions also occur, although the mechanism is not
well understood; true iodine allergies are very rare.
Contrast Agents
High-Osmolality Agents  Low-Osmolality Agents
(Higher risk of reaction) (Lower risk of reaction)
◆ Diatrizxoate sodium (Hypaque)
◆ Iodamide meglumine
◆ Iothalamate meglumine
◆ Oral cholecystographic
agents (Telepaque)
Risk Factors for Adverse Reactions to Contrast
The following conditions are associated with an increased risk of
adverse reaction to ICM:
■ Previous reaction
■ Asthma (severe reactions are five to nine times more common)
■ Allergy
■ Diabetes (for nephropathic reactions)
■ Renal failure (for nephropathic reactions)
■ Severe cardiac disease
■ Dehydration (for nephropathic reactions)
■ Extremes of age (newborn or 65 years old)
■ Seizure disorder
■ Liver disease
■ Multiple myeloma (if renal involvement)
◆ ioxaglate meglumine (Hexabrix)
◆ gadodiamide (Omniscan)
◆ gadoteoridol (ProHance)
◆ iodixanol (Visipaque)
◆ iopamidol (Isovue)
◆ ipromide (Ultravist)
◆ ioversol (Optiray)
Contrast Reaction Prevention Strategies
■ Use low-osmolality, nonionic agents.
■ Avoid concurrent administration of nephrotoxic drugs.
■ Discontinue metformin (Glucophage) the day of the test and
do not administer for 48 hr. Resume only after renal function
has normalized.
■ Use an anaphylactoid reaction prevention protocol (indicated
for patients with prior contrast reaction):
◆ Corticosteroid protocol: either methylprednisolone 32 mg at
12 and 2 hr before contrast or prednisone 50 mg at 13, 7,
and 1 hr before contrast.
◆ Diphenhydramine 50 mg 1 hr before contrast.
■ Use an acute renal failure prevention protocol:
◆ Avoid concurrent nephrotoxic drugs.
◆ Use low-osmolality contrast material.
◆ Allow 2–5 days between IV contrast procedures.
■ Hydrate before and after procedure:
◆ 1
/2 NS or NS, 100 mL/hr 4 hr precontrast and 24 hr
postcontrast (adjust for congestive heart failure) OR
◆ Oral (noncaffeinated) fluid 500 mL before contrast and 2500
mL over 24 hr postcontrast.
■ Adjust IV contrast dose:
◆ Contrast dose: (5 mL/kg)/(serum creatinine).
◆ Maximum total dose: 300 mL.
In patients with renal failure, metformin, which is excreted by the
kidneys, may build up to dangerous levels causing potentially
fatal lactic acidosis. Since administration of iodinated contrast
media (ICM) can cause acute renal failure, particularly in those
at risk for renal compromise (diabetics), metformin should be
temporarily discontinued.
Metformin should be discontinued the day of testing and
withheld for 48 hr after testing. It should be restarted only after
renal function has returned to normal.
Reactions to Iodinated Contrast Media (ICM)
Signs and Symptoms Treatment
Mild symptoms: scattered urticaria,
pruritus; rhinorrhea; nausea,
vomiting; diaphoresis; coughing; and
Moderate symptoms: persistent
vomiting; diffuse urticaria; headache;
facial and or laryngeal edema; mild
bronchospasm; dyspnea;
palpitations, tachycar-dia, bradycardia; hypertension;
abdominal cramps.
Severe symptoms: life-threatening
arrhythmias (V-tach); hypotension;
overt bronchospasm; laryngeal
edema; pulmonary edema; seizures;
syncope; cardiopulmonary arrest
✓ Observe for progression to more severe
reaction, which requires immediate
✓ Administer antihistamines for itching or
prochlorperazine for nausea and vomiting
if necessary.
✓ Provide O2 at 10–12 L/min via face mask.
✓ Monitor vital signs every 5 min.
✓ Administer antihistamines, initiate IV
access with NS or D5W.
✓ Possible administration of epinephrine,
steroids, and bronchodilators.
✓ Administer epinephrine 0.3–0.5 mg subQ
every 10–20 min and methylprednisolone
50 mg IV.
✓ Give beta agonist inhaler (e.g., albuterol)
for bronchospasm.
✓ Call a code.
✓ Manage ABCs: Monitor breathing and
vital signs continuously.
✓ Maintain or initiate IV access.
Prepare for intubation and resuscitation.
(Continued on following page)
Signs and Symptoms Treatment
Occurs within
7 days of the
injection of
Decreased heart rate (60 bpm) and
hypotension possibly accompanied
by nausea, vomiting, diaphoresis,
and mental status changes. Can
lead to cardiovascular collapse and
death if untreated.
Decreased urine output. Diagnosis of
contrast-associated renal failure:
serum creatinine elevation of 25%
within 3 days of contrast.
Flu-like symptoms: fatigue, upper
respiratory tract congestion, fevers,
chills, nausea, vomiting, diarrhea,
abdominal pain; pain in the injected
extremity; rash; dizziness and
headache; pruritus; parotitis; joint
pain; constipation; and depression.
✓ Provide O2 at 10–12 L/min via face
✓ Monitor vital signs every 5 min.
✓ Administer IV fluids.
✓ Atropine for vasovagal responses.
✓ Discontinue other nephrotoxic drugs if
✓ Space studies up to 5 days apart to
allow kidneys to recover.
✓ Hydrate patients 12 hr before and 2 hr
after study.
✓ Monitor lab values, intake, and output.
✓ Usually resolves spontaneously with
little or no treatment.
X-ray with contrast to examine a joint and its surrounding soft
tissues (cartilage, ligaments, bursa, joint capsule). Commonly
done of the knee and shoulder but hip, wris,t and ankle are often
done as well. Informed consent required. Potential Complications:
Infection, reaction to contrast (unlikely since contrast is not
administered IV).
■ Assess persistent, unexplained joint pain.
■ Evaluate injuries to joint structures.
■ Assess for tumor, tears, ruptures, cysts, and other abnormalities.
The patient lies supine on the x-ray table with the joint exposed.
Lidocaine is injected to anesthetize the skin. Next, a needle is
inserted into the joint space to aspirate synovial fluid for analysis
and to minimize dilution of the contrast. The syringe is replaced
with a syringe containing contrast, which is injected into the joint.
To distribute the contrast throughout the joint, the patient either
walks a bit or has the joint manipulated through its range of
Films are taken with the joint in various positions.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about previous reactions to contrast or other risk
factors for adverse reaction to contrast (see page 79).
■ Inform the patient that test will take about 30 min.
■ Prepare the patient to expect some discomfort when the contrast
is injected.
■ Assess vital signs and pain level.
■ Assess patient for reaction to contrast (see Table, pages 81-82).
■ If ordered, apply ice to joint and administer an analgesic.
■ If knee has been evaluated, the patient will likely have an elastic
wrap applied. Inform patient to leave wrap on per physician’s
■ Advise patient to minimize joint rotation and/or weight
bearing for 1–2 days.
■ Teach patient to monitor for and report signs and symptoms
of infection (fever, pain, swelling warmth over joint, redness
or drainage at puncure site).
Negative contrast arthrogram of the knee
Arteriogram (Angiogram, Arteriography)
Rapid-sequence x-rays following administration of IV contrast to
evaluate vascular conditions such as aneurysm, stenosis,
blockage, or neoplasm. Digital subtraction angiography (DSA)
removes the bony structures from the picture, thereby
enhancing visualization. Performed in interventional radiology
suite or other special procedures area. See also Cardiac
Catheterization in Other Studies Tab. Common studies include:
◆ Renal arteriogram
◆ Carotid arteriogram
◆ Cerebral arteriogram
◆ Lower extremity arteriogram
◆ Pulmonary arteriogram
Informed consent required. Potential complications include
reaction to contrast, hemorrhage from arterial puncture, arterial
embolism, renal failure secondary to IV contrast, stroke,
thrombosis and arterial occlusion distal to puncture site,
hematoma, pseudoaneurysm, neurovascular damage.
■ Evaluate patency, size, and shape of blood vessels.
■ Assess for plaque, emboli, or other explanation for impeded
blood flow.
The patient is placed supine on the x-ray table. An intravenous
line, if not already present, is inserted and the patient is
connected to an ECG monitor.
After prepping, a small incision is made in the groin to access
the femoral artery or into the arm to access the brachial artery.
Under fluoroscopy, a wire is threaded into the artery and along
the arterial system until it is near or in the artery to be
examined. A catheter is then threaded over the wire and the
wire is removed. The contrast material is injected either by
hand or with a preset automated injector while a rapid series of
x-rays are taken.
The patient may receive sedation or possibly pain medication at
the initiation of or during the procedure.
Throughout the procedure, the patient’s vital signs are assessed
and the peripheral pulses distal to the catheter insertion site are
After the study is complete, the catheter is removed and
pressure is applied over the puncture site for 15 min. A
pressure dressing is then applied.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about iodine or shellfish allergies.
■ Check that the patient has been NPO for the prescribed
amount of time (2–8 hr).
■ Locate and mark peripheral pulses distal to the proposed
puncture site to facilitate pulse assessment during and after
angiogram. (If pulses are absent before the procedure,
document this finding. Assess both by palpation and with
■ Compare warmth, color, and strength of pulse in extremity to
be used for vascular access to the nonprocedure extremity.
Document preexisting differences so that postprocedure
assessments can be properly interpreted.
■ Check that preprocedure coagulation studies are available. If
results are out of range, document and notify physician and
personnel in the unit where the procedure will be performed.
■ Ask if patient is taking metformin (Glucophage). Inform
physician if yes and check for orders to hold the medication
for 48 hr postprocedure. Ascertain that alternative to
metformin has been ordered to cover blood glucose
■ Assess vital signs.
■ If a cerebral arteriogram is scheduled, assess the patient’s
neurologic status carefully to establish the baseline against
which postprocedure assessments can be compared.
■ Tell the patient:
◆ the test takes 1–2 hr
◆ there is minor discomfort associated with the insertion of
the catheter but that sedative and analgesic medication will
be available
◆ he or she will feel a sensation of warmth when the contrast
is injected but that it will only last a few seconds
◆ to report feelings of dizziness, itching, nausea, or other
unusual feeling to radiology staff
◆ he or she may feel bladder fullness during the procedure
secondary to the contrast’s diuretic effect
■ Explain postprocedure care and the importance of maintaining
bedrest for several hours after the procedure.
■ Asssess the patient’s distal pulses and vital signs every 15 min
until stable and per facility protocol.
■ Assess puncture site every 15 min for swelling, hematoma, or
bleeding. Assess if pressure dressing is intact. Apply sandbag
to site. Report bleeding or disruption of pressure dressing
immediately.  If site is bleeding, call physician immediately
and apply strong pressure with both hands until help arrives.
■ Assess neurovascular status of extremity: In addition to
palpating peripheral pulses, note skin temperature, color, and
capillary refill time; ask about pain, numbness, or tingling;
have the patient demonstrate mobility of hand or foot
(depending on puncture site) without flexing or extending the
■ Continue to monitor the patient for several hours. Assist
patient to stand and walk when ambulation can be resumed.
■ For the patient who will be discharged to home following the
procedure, explain that he or she must monitor the puncture
site for bleeding, pain, swelling, and abnormal skin color or
temperature change in the arm or leg.
■ Advise the patient not to engage in strenuous activity for
12–24 hr and not to take a hot bath or shower.
Barium Enema (BE)
X-ray and fluoroscopy of the colon after instillation of barium
sulfate to enhance images. Fluoroscopy is used to visualize the
barium as it moves through the large intestine. Air may be
insufflated into the colon to provide additional contrast and make
the mucosa more visible. Potential Complication: retained barium
in the colon causing obstruction or impaction.
■ Assess for tumor, polyps, inflammatory disorder, cause of rectal
bleeding, change in bowel habits, stricture, tumor, diverticula,
and megacolon.
■ BE is contraindicated in patients wih suspected bowel perfora-tion. In this case, evaluation of the large intestine is accompli-shed using water-soluble ICM such as Gastrografin and no bowel
The patient lies on the x-ray table for a plain film of the abdomen.
Next, barium is instilled into the colon using a rectal tube or, if the
barium is administered through an ostomy, a Foley catheter.
Transit of the barium through the large intestine into the terminal
ileum is observed under flouroscopy. Spot films from various
views and with the patient in different positions are taken of
significant findings. After all films are taken, the barium is
aspirated from the colon and the rectal tube is removed. The
patient will expel residual barium. An additional film is taken after
the evacuation of barium.
■ See General Pretest Patient Education in Tools Tab.
■ The patient will have a clear liquid diet the evening before
the test and nothing by mouth, including medication, after
■ The patient should drink plenty of fluids the day before the test.
■ The day before the test, the patient will begin the bowel prep,
which involves drinking magnesium citrate or other product in
the afternoon and taking biscodyl tablets (usually three 5-mg
tabs) in the early evening.
■ The morning of the test, the patient will use a biscodyl
suppository and/or a cleansing enema until the returned
material is clear of fecal matter.
■ The patient should be told that the instillation of the barium
(and air, if used) can cause cramping and bloating.
■ Reassure patient that radiology staff know that most people
find the test embarassing and will help the patient be as
comfortable as possible.
■ Inform the patient that testing will take 45–90 min.
■ Assess for dehydration or electrolyte imbalance, especially in
older adults.
■ Retained barium can cause an impaction or obstruction. The
patient should take a mild laxative or an enema to ensure that
no barium is retained. Stool may appear light colored for a
few days.
Barium Swallow
X-ray with contrast medium (barium solution) to enhance images
of the esophagus (also called esophagography). A water-soluble
iodinated contrast medium (ICM) such as Gastrografin may be
used if perforation or obstruction is suspected since barium, if
deposited in the soft tissues, can cause a serious inflammatory
■ Assess for anatomic deformity, stricture, tumor, foreign body,
reflux disease, swallowing disorder, esophageal spasm.
■ Evaluate epigastric pain or regurgitation.
A plain film is taken with the patient standing or lying supine on
the x-ray table. The patient then stands in front of a fluoroscopy
screen and swallows the contrast. The structure and function of
the esophagus are evaluated and spot films may be taken. The
patient is then strapped to the x-ray table and the table is tilted in
various positions as additional films are taken.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about iodine or shellfish allergies if ICM will be used.
■ The patient will be NPO for 8 hr prior to the procedure.
■ The patient will have to remove jewelry from the head and neck.
■ Although the procedure is not painful, some patients may not
like drinking the contrast media.
■ If the patient has had barium: inform the patient that a mild
laxative and extra fluids will help with the elimination of the
barium. Inform the patient that stools will appear white or light
colored. Instruct patient to notify health care provider if
■ If the patient has had an ICM (iodinated contrast medium):
Monitor for anaphylactic, cardiovascular, nephropathic, or
delayed reactions to contrast. See preceding Table, Reactions to
Iodinated Contrast Media (ICM). Inform patient that some
patients experience diarrhea from water-soluble ICM.
Cystography (Cystourethrogram, Voiding
Cystourethrogram, Cystogram)
X-ray and fluoroscopy with contrast medium to visualize bladder
and urethra structure and function. (Also see Nuclear
Cystogram in Nuclear Studies Tab.) Informed Consent required.
Potential Complications: UTI, reaction to contrast (unlikely
since contrast is not administered IV).
■ Evaluate structure and excretory function of the bladder and
■ Assess for vesicoureteral reflux.
■ Detect obstruction to urine flow (stones, stricture, stenosis,
prostatic enlargement).
■ Evaluate cause of recurrent UTI.
The patient is placed supine or in the lithotomy position on the
x-ray table. A catheter is placed and approximately 300 mL
(adult dose) of contrast material is instilled into the bladder. X-rays are taken of the bladder while it is filled with contrast.
If a voiding cystourethragram is ordered, the catheter is then
removed and the patient voids while more films are taken.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about previous reactions to contrast or other risk
factors for adverse reaction to contrast (see page 79).
■ Inform the patient that test will take about 30 min.
■ Explain that patient will feel a brief sensation of pushing when
catheter is inserted.
■ Assess patient for reaction to contrast.
■ Monitor urine output and inform patient to monitor at home.
■ Tell patient to drink plenty of fluids unless contraindicated.
■ Assess for signs/symptoms of UTI and inform patient to report
fever, malaise, frequency, urgency, bladder or flank pain.
Enteroclysis (Small Bowel Enema)
Fluoroscopy and spot x-rays with contrast (barium) to visualize
the small bowel. Requires duodenal intubation. Informed
Consent required. Potential Complications: complication of
intubation or sedation, retained barium.
■ Evaluate persistent nausea and vomiting.
■ Assess for stricture, fistula, inflammation, obstruction, tumors,
or intestinal motility problems
The patient may have an IV placed and be sedated for the
The patient sits for placement of the duodenal tube. An
anesthetic gel is applied to the tube and the inside of the
nostril. The tube is advanced down the esophagus and into the
stomach while the patient swallows. The patient is then placed
supine, and the position of the tube is checked with
fluoroscopy. A guide wire is placed down the tube so that it can
be advanced into the pyloric sphincter and the duodenum.
After proper placement of the tube, barium is infused into the
tube and the progression of the barium is observed with
fluoroscopy. The patient may need to assume different
positions. Several spot films are taken.
■ The patient usually will need to be on a clear liquid diet for at
least 24 hr prior to the test.
■ A laxative and/or enema the evening before or the morning of
the test are also usually required.
■ Inform the patient that the test is not painful but that some
discomfort may be experienced when the tube is inserted.
■ Inform the patient that the test can take up to 6 hr to
■ Monitor vital signs and recovery from sedation (if used).
■ Retained barium can cause an impaction or obstruction. The
patient should take a mild laxative or an enema to ensure that
no barium is retained.
■ Inform the patient that stool may appear light colored for a
few days.
■ Patients with chronic constipation should take a mild laxative
for several days until stool color returns to normal.
X-ray and fluoroscopy with contrast to visualize uterine cavity
and fallopian tubes. Potential Complications: Infection,
perforation of the uterus, reaction to contrast (unlikely since
contrast is not administered IV).
■ Assess patency of fallopian tupes and structural integrity of
■ Detect displaced IUD, tubal preganancy.
■ Assess cause of repeated miscarriage.
The patient lies on the table in the lithotomy position. A
speculum is placed in the vagina to visualize the cervix. A
flexible catheter is placed through the cervical opening into the
uterine cavity.
Contrast is slowly injected through the catheter into the uterus.
An x-ray is taken as the uterine cavity is filling. Additional
contrast is injected so that the fallopian tubes fill and more x-rays are taken including an oblique view.
Once the instruments are removed, the patient remains on the
table for several minutes until cramping subsides.
■ Ascertain that the patient is not pregnant and that last
menstrual period occurred 7–10 days prior to test date.
■ Inform the patient that testing takes approximately 30 min.
■ Prepare the patient to expect mild to moderate cramping,
which can be relieved with medications.
■ Some radiologists request a bowel prep (laxative the evening
before, suppository or enema in the morning) and/or a
cleansing douche
■ A pretest sedative such as oral diazepam may be given.
■ Assess vital signs, pain level, amount and characteristics of
vaginal discharge.
■ Some women experience dizziness; assess patient for
■ Most women experience cramping for several minutes after
the procedure, but some may have cramps for several hours.
A mild analgesic such as ibuprophen can be given.
■ Teach patient to assess for and report signs or symptoms of
infection such as fever, pelvic pain and tenderness, or
purulent discharge.
■ Teach patient to assess for and report signs or symptoms of
uterine perforation: abdominal pain and distension, vaginal
bleeding, signs and symptoms of peritonitis.
■ Tell the patient to expect to have vaginal discharge for a few
days after the test. This discharge is the contrast agent and is
harmless. It may be blood tinged but should not be frankly
X-rays and fluoroscopy with contrast to provide visualization of the
spinal subarachnoid space and the spinal canal. Myelography is
often combined with computed tomography (CT scan), which is
then called called CT myelography. Magnetic resonance imaging
(MRI) has replaced myelography for many indications. Informed
consent required. Potential Complications: Severe headache; CSF
leak; brain herniation; seizures; meningitis; puncture of the spinal
cord, aorta, or vena cava; severe reaction to contrast.
■ Assess signs and symptoms consistent with narrowing of the
spinal canal.
■ Assess patients with peripheral neurologic deficits.
■ Detect spinal stenosis, herniated disk, tumor, or infection.
■ Assess changes in bone structure caused by arthritis or
ankylosing spondylosis
The patient is placed prone or in a side-lying position for lumbar
puncture. Under fluoroscopy to verify proper placement, a needle
is inserted and 15 mL of cerebrospinal fluid (CSF) is removed. The
patient is positioned prone and secured to the x-ray table with
straps. Then 15 mL of water-soluble contrast agent is then injected
into the spinal canal and the x-ray table is tilted to distribute the
contrast. Progress of the contrast is fluoroscopically observed.
Lesions or obstructions to flow are apparent and spot films are
taken. After all views are obtained, the needle is removed and the
site is dressed.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about previous reactions to contrast or other risk
factors for adverse reaction to contrast (see page 79).
■ In addition to other medical history questions, ask the patient
about history of seizures or use of medications that can lower
seizure threshold. Ascertain that patient has discontinued seizure
threshhold–lowering drugs for 48 hr before the test (see Table
■ In addition to drugs that lower the seizure threshold,
anticoagulants should also be withheld for 48 hr before
■ Foods and fluids restrictions vary with the type of contrast
used. Some patients will be NPO for 8 hr prior to the
procedure and will require a laxative or enema. Some patients
may have clear liquids before the test and no bowel prep.
Check with the radiology department for details.
■ Let the patient know that some patients experience discomfort
during the study and that sedative or analgesic medication
will be provided if necessary.
■ Inform the patient that an IV may be placed and fluids or
medications (sedatives or anticonvulsants) may be given.
■ Have the patient void before the test.
■ Tell the patient that the test takes 45 min (longer if combined
with CT scan) and that he or she will be monitored in the
radiology department or the hospital for several hours after
the procedure.
■ Proper positioning of the head after myelogram is very
important in preventing a headache. If an oil-based contrast
material was used (rare), the patient must remain flat in bed
for 24 hr.
■ If a water-based contrast material was used, the patient must
remain in bed for 24 hr, but the head of the bed can be
elevated 15–30 degrees.
■ Assess vital signs, neurologic status, and pain level every 30
min for 4 hr, then every 4 hr for 24 hr.
■ Assess for numbness, tingling, or diminished mobility of
lower extremities.
■ Assess patient’s ability to void.
■ Encourage fluid intake to help excrete contrast.
■ Assess puncture site for bleeding or drainage.
■ Assess patient for reaction to contrast (see Table, pages
■ Document and report any postprocedure problems promptly.
Medications That Lower Seizure Threshold and May Be
Withheld for 48 Hr Prior to a Myelogram
amphetamine mixture
Operative or T-Tube Cholangiogram
X-ray and fluoroscopy of the common bile duct using an
iodinated contrast medium (Hypaque) to enhance visualization.
Done during gallbladder surgery or 7–10 days after
cholecystectomy. Informed Consent required. Potential
Complications: severe adverse reaction to contrast.
■ Evaluate biliary duct patency before removal of T-tube or, if
performed during surgery, to visualize biliary tree and thus
minimize risk of operative injury to the common bile duct.
■ Assess for strictures, gallstones, fistula, or tumor.
T-Tube Cholangiogram: The T-tube is clamped, usually the day
before the procedure. In the radiology department, the patient
is placed on the x-ray table. The T-tube is unclamped and
contrast medium is injected into it. The contrast is visualized
with fluoroscopy as it moves through the duct system. The tube
is clamped while various pictures (prone, side-lying, erect) of
the right upper quadrant (RUQ) are taken.
Intraoperative cholangiogram: During surgery a catheter is
inserted into the common bile duct. Contrast is injected into the
catheter and x-rays are taken.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about iodine or shellfish allergies if ICM.
■ T-tube cholangiogram: NPO for 1 meal prior to test.
Administer an enema 1 hr before test.
■ Tell the patient that he or she may experience pressure as the
contrast is injected. Some patients may experience nausea,
vomiting, cramps, or diarrhea from the contrast.
■ Inform the patient that testing usually takes about 30 min.
■ Monitor for anaphylactic, cardiovascular, nephropathic, or
delayed reactions to contrast. See preceding Table, Reactions
to Iodinated Contrast Media (ICM).
■ Monitor for dehydration or electrolyte imbalance if patient
experiences vomiting and/or diarhhea.
■ Check if T-tube has been removed (if postop findings are
normal). Apply a dry sterile dressing to the site.
■ Check orders to see if T-tube is to be left clamped or
■ Assess T-tube insertion site for pain or swelling.
Oral Cholecystogram (OCG)
X-ray of the gallbladder with iodinated contrast medium
(Telepaque or Oragrafin) to enhance visualization. Infrequently
used since ultrasound, CT scan, and nuclear scans give better
results (refer to appropriate Tabs). Informed Consent required.
Potential Complication: severe adverse reaction to contrast.
■ Assess RUQ/epigastric pain and other symptoms associated
with gallbladder disorders.
After proper preparation the evening before the test (see below),
the patient lies on the x-ray table while pictures are taken from
varying views. The patient may be given a high-fat meal to
stimulate gallbladder contractions, which are observed with
fluoroscopy. Additional films are taken as the contrast moves
through the common bile duct.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about iodine or shellfish allergies.
■ The patient will eat a low-fat meal the evening before the test
and will be NPO after midnight.
■ The patient will take six Telepaque tablets 5 min apart 2–3 hr
after the evening meal.
■ An enema may be prescribed the morning of the test.
■ Although the procedure is not painful, some patients may
experience nausea, vomiting, cramps, or diarrhea from the
■ Inform the patient that testing may take up to 2 hr.
■ Monitor for anaphylactic, cardiovascular, nephropathic, or
delayed reactions to contrast. See preceding Table, Reactions
to Iodinated Contrast Media (ICM).
■ Monitor for dehydration or electrolyte imbalance if patient
experiences vomiting and/or diarhhea.
Percutaneous Transhepatic  Cholangiogram  (PTC)
Fluoroscopic visualization of the bile ducts with spot films of
significant findings. Performed in interventional radiology.
Contrast medium is administered through a fine needle
inserted through the skin into the liver and into a bile duct.
Informed consent required. Potential complications: sepsis,
bleeding, peritonitis, severe adverse reaction to contrast.
■ Distinguish between obstructive and nonobstructive jaundice
and pancreatitis.
■ Assess patients in whom ERCP (see Scopes Tab) has been
■ Assess cause of obstructive jaundice.
■ Evaluate persistent upper abdominal pain after
■ Establish external drainage of the biliary system as a palliative
measure for patients with nonresectable malignant disease.
The patient lies on the x-ray table. A peripheral IV line is inserted
and a sedative and/or pain medication are administered
(sometimes a sedative is administered before the test). A local
anesthetic is administered into the right upper abdominal wall.
The patient holds his or her breath and a fine needle is inserted
between the 10th and 11th intercostal space, midclavicluar line.
The needle is advanced until it enters a bile duct, after which
the introducer is removed and contrast medium is injected into
the biliary system.
The movement of the contrast through the bile ducts is observed
on the fluoroscope, which shows whether the bile moves freely
or is obstructed. The patient is helped to assume a variety of
positions while spot films are taken.
After all films have been taken, the contrast is aspirated from the
biliary ducts, the needle is removed, and a dry sterile dressing is
A catheter may be left in place if external biliary drainage is
■ See General Pretest Patient Education in Tools Tab.
■ Check that patient has been NPO for 8 hr and clotting times, PT,
and platelet count results are normal and available on the chart.
Coagulation studies are frequently abnormal in patients with
liver disease.
■ Make sure that pretest antiobiotcs have been administered.
■ Ask patient about previous reactions to contrast or other risk
factors for adverse reaction to contrast (see page 79).
■ Ascertain that within the preceding week the patient has not
taken NSAIDs, aspirin, or medications that affect bleeding times.
■ Administer pretest sedative, if ordered.
■ Explain that the patient may feel discomfort when the needle
penetrates the liver, pressure, or brief discomfort in the right
subscapular area. Reassure the patient that medication will be
given to enhance comfort.
■ The patient will need to remain still and hold his or her breath
for short periods during the test.
■ Tell the patient testing usually takes between 30 and 60 min.
■ Monitor for anaphylactic, cardiovascular, nephropathic or
delayed reactions to contrast. See preceding Table, Reactions to
Iodinated Contrast Media (ICM).
■ Assess vital signs frequently according to policy.
■ The patient should maintain bedrest for 6 hr postprocedure.
■ Monitor for bleeding from puncture site, swelling around
puncture site. Notify physician or NP immediately if the
patient has right abdominal or shoulder pain (indicates
bleeding), fever, dizziness, drop in blood pressure, tachycardia,
or heme  stool.
■ Continue antibiotics on schedule.
PTC Approach
Percutaneous transhepatic cholangiogram.
Needle insertion site for percutaneous transhepatic cholangiogram.
bile ducts
bile duct
Pyelogram, Antegrade and Retrograde
Retrograde or antegrade pyelography is performed when IVP results are inadequate or IVP is
contraindicated. Informed Consent required. Potential Complications: severe adverse reaction
to contrast; adverse reaction to anesthesia, other risks of surgery (retrograde pyelogram).
Antegrade Pyelogram Procedure and Care
Procedure Pre- and Posttest Care
Visualizes stones,
obstructions in the
urinary system.
Performed in
Kidneys are located by US or
CT; overlying skin is cleaned
with antiseptic and local
anesthetic is injected.
Under fluoroscopy, a needle
with a manometer attached
is inserted into the kidney
and pressure readings are
Contrast is injected into the
X-rays are taken of kidney’s
upper- collecting system.
A nephrostomy tube may be
left in the kidney for
✓ Follow preoperative orders regarding
bowel prep and NPO status.
✓ Patient will require standard post-procedure assessment and VS
✓ Monitor needle insertion site for
bleeding or hematoma. Provide
nephrostomy tube care, if indicated.
✓ Monitor fluid intake and urinary
output for at least 24 hr.
✓ Assess urine for blood.
✓ Call physician or NP if patient has not
voided within 8 hr of the procedure, if
bladder is distended or painful, or if
voiding small amounts.
✓ Assess for signs of infection, such as
chills, fever, and hypotension.
Retrograde Pyelogram Procedure and Care
(Retrograde: moving
backward against
usual direction of
Visualizes stones,
tumors, obstruc-tions in the urinary
system. Performed
in the OR under
general anesthesia
in conjuction with
Two catheters are inserted
through the cystoscope
into the ureters.
Contrast is injected into the
ureters and kidney.
Contrast is observed under
fluoroscopy and x-rays of
the entire urinary tract are
✓ Follow preoperative orders
regarding bowel prep and NPO
✓ Patient will require standard
postoperative assessment and vital
sign monitoring.
✓ In addition:
✓ Monitor fluid intake and urinary
output for 24 hr.
✓ Assess urine for blood.
✓ Call physician or NP if patient has
not voided within 8 hr of the
procedure, if bladder is distended
or painful, or if voiding small
amounts frequently.
✓ Assess for signs of infection, such
as chills, fever, and hypotension.
Pyelogram, Intravenous (IVP, Excretory
Urogram, EU, ExU)
X-ray with contrast medium to visualize the kidneys, renal pelvis,
ureters, and bladder. Also called excretory urography (ExU) or
IV urogram (IVU). Being replaced by CT urogram (see CT Tab)
Informed Consent required. Potential Complications: severe
adverse reaction to contrast.
■ Evaluate structure and excretory function of the renal system.
■ Assess patients with flank/kidney pain.
■ Asses for kidney stones.
■ Investigate cause of hematuria.
■ Evaluate suspected obstruction, structural abnormalitiy, or
trauma to the urinary system.
The patient is placed supine on the x-ray table and an abdominal
flat plate is taken to determine if any barium, stool, stones, or
gas will obscure visualization. Next, an IV line is inserted and
the contrast is injected. The contrast reaches the kidneys via the
bloodstream, where it is filtered out of the blood and excreted
through the ureters into the bladder. Films are taken
approximately every 5 min until the contrast reaches the
bladder. These x-rays reveal tumors, cysts, stones, or other
structural and functional abnormalities. Once the contrast
reaches the bladder, the patient is asked to void and another
film is taken. This will reveal if the bladder empties completely.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about previous reactions to contrast or other risk
factors for adverse reaction to contrast (see page 79).
■ The patient should be well-hydrated and should increase fluid
intake the day before the test. Check BUN; if elevated, notify
■ The patient will not be allowed foods in the 8 hr preceding the
test and may be NPO. In some cases, the patient may have a
clear liquid breakfast.
■ A bowel prep may be ordered the evening before or the morning
of the test.
■ Ascertain that patients on metformin (Glucophage) have
withheld the medication the day of the test.
■ The patient should void immediately before the test.
■ Inform the patient that the test will take 30 to 60 min.
■ Monitor for anaphylactic, cardiovascular, nephropathic, or
delayed reactions to contrast. See preceding Table, Reactions to
Iodinated Contrast Media (ICM).
■ Ensure adequate oral or IV hydration.
■ Monitor urine output and inform patient to monitor at home.
■ Ensure that renal function is evaluated before metformin is
resumed 48 hr after the test.
■ Patient may resume pretest activity level and diet.
Upper GI Series (UGI)
X-ray and fluoroscopy with contrast medium (usually barium
sulfate) to enhance images of the lower esophagus stomach,
duodenum, and upper jejunum. Allows visualization of the
digestive system at work as barium moves through it. A water-soluble iodinated contrast medium (ICM) such as Gastrografin
may be used if perforation is suspected since barium, if deposited
in the soft tissues, can cause a serious inflammatory response.
When combined with evaluation of the entire small bowel is called
UGI with small bowel follow-through.
■ Assess for ulcers, stricture, tumor, reflux disease, hernia, and
The patient sits or stands behind the fluoroscopy machine and is
asked to swallow the barium (8–16 oz). Passage of the barium
through the upper GI tract is filmed as the patient drinks.
After ingestion of the barium, x-ray images are obtained with the
patient in different positions (supine, side-lying, prone) and from
different views (PA, AP, lateral, and oblique).
If needed, enhancement of the structures can be obtained by
having the patient swallow baking soda crystals or drink barium
through a perforated straw (called double-contrast). The air
smoothes out the gastric rugae (wrinkles and folds), which
makes the anatomy clearer.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about iodine or shellfish allergies if ICM will be
■ The patient will be NPO for 8 hr prior to the procedure.
■ The patient will have to remove jewelry on the trunk, head, or
neck. If jewelry has psychological or spiritual significance, the
patient may hold the jewelry during the procedure.
■ Although the procedure is not painful, some patients may not
like drinking the barium.
■ Inform the patient that testing may take up to 5 hr, although
the study usually is completed within 2 hr.
■ If the patient has had barium: inform the patient that a mild
laxative and extra fluids will help with the elimination of the
barium. Inform the patient that stools will appear white or
light colored. Instruct patient to notify health care provider if
■ If the patient has had an ICM (iodinated contrast medium):
Monitor for anaphylactic, cardiovascular, nephropathic, or
delayed reactions to contrast. See preceding Table, Reactions
to Iodinated Contrast Media (ICM). Inform patient that some
patients experience diarrhea from water-soluble ICM.
■ Instruct the patient to notify health care provider if
Venogram, Lower Extremity
X-ray with contrast to enhance visualization of venous system.
Requires informed consent. Potential complications: severe
adverse reaction to contrast, renal failure, dislodgement of
venous thrombi.
■ Detect deep vein thrombosis (DVT)
The patient is placed on the x-ray table, which is tilted at an
angle between 30 and 45 degrees.
A tourniquet is placed above the ankle and sometimes on the
thigh. (This is to diminish blood flow in the peripheral veins
thereby allowing contrast to fill the deep veins.) An IV is started
in the foot and the contrast medium is injected over 2–4 min. A
series of x-rays are taken as the contrast moves through the
veins. Alternatively, the progression of the contrast can be
viewed using fluoroscopy with spot films taken as needed.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about iodine or shellfish allergies if ICM will be
■ The patient may be asked to take only clear liquids for 2 hr
prior to the procedure.
■ Although the procedure is not painful, some patients may
have mild discomfort as the catheter is inserted.
■ Inform the patient that testing takes 30–90 min.
■ Assess patient’s vital signs after the procedure. Monitor for
reaction to contrast.
■ Encourage fluids.
■ Observe puncture site for bleeding, hematoma, signs or
symptoms of infection.
Overview of CT Scanning
■ A CT scan is a specialized x-ray that takes cross-sectional
pictures of all types of tissue.
■ CT scans are sometimes called CAT scans. The “A” refers to
the word axial, which is a particular orientation of the image.
Other orientations are available now, so the A has been
■ It is used extensively in diagnosing disease and injury of the:
◆ Brain, cerebral blood vessels , eyes, inner ear, and sinuses.
◆ Neck, shoulders, cervical spine, and blood vessels.
◆ Chest, heart, aorta, lungs, and mediastinum.
◆ Thoracic and lumbar spine.
◆ Upper abdomen, liver, kidney, spleen, and pancreas.
◆ Skeletal system including bones of the hands, feet, ankles,
legs and arms, and jaws.
◆ Pelvis and hips, reproductive system, bladder, and GI tract.
■ It is also used to diagnose cancers, including lung, liver, and
pancreatic cancer and measure tumor size and assess
involvement in other nearby tissues.
■ Fluoroscopic CT imaging is used to guide minimally invasive
procedures such as:
◆ Drainage of fluid collections (cysts, abscesses, lymphoceles,
◆ Biopsy.
◆ Injection of pain medications into a spinal disc space.
◆ Dynamic study of knee or elbow motion, swallowing, or
study of the larynx.
◆ Embolization to stop bleeding, for example, after liver or
spleen trauma.
■ Computed tomography angiography (CTA) is a less invasive
method for examining blood vessels.
■ Patients over 300 lb may be unable to undergo CT scanning.
■ It is important that patients lie very still during imaging. Any
motion will blur the images necessitating repeat scans.
■ The CT scan itself usually takes only a few minutes to
complete but the patient should allow up to 2 hr for the test.
How CT Scans Work
■ A CT scanner can be described as a square doughnut because
of its shape (square) and the large opening in the center.
■ During the scan the patient lies on the CT table, which is
advanced into the opening incrementally (in fractions of an
inch) so that the scanner can take a series of images.
■ Inside the ring-shaped scanner are the x-ray tube and the
detector. (See Figures.) The detector takes the place of film
used in conventional x-rays. The x-ray tube and the detector
are mounted opposite each other on the circular, rotating
■ To obtain the CT image “slice,” the frame rotates and the x-ray
tube and the detector spin around the patient.
■ Each time the x-ray tube and detector make a complete 360-degree rotation, hundreds of snapshots are obtained. These
snapshots are then reconstructed by a computer into a two-dimensional image of the slice of tissue that was scanned.
(See Figures.)
■ The slices can be from 1–10 mm thick. The thickness is
controlled by lead shutters called the collimator.
■ The CT computer can detect over 200 shades of gray and can
therefore better distinguish different types of tissue. A
conventional x-ray can detect only 30 shades of gray.
■ The images can also be enhanced with contrast media or
manipulated to provide a three-dimensional display.
■ A 3D-CT scan takes many more x-ray images in smaller
sections and at many different angles.
■ Spiral or helical CT scans are capable of imaging entire
anatomic regions in 20–30 sec.
■ This is made possible by having a rotating frame that doesn’t
have to stop and restart for each new 360-degree slice.
■ Multislice CT spiral scanners collect more slices and more
data than other spiral scanners and can present even better
X-Ray tubes
Exterior of a CT Scanner
Interior of a CT Scanner
How the CT Image Is Obtained
X-Ray tube
Sagittal, coronal, and axial views.
Axial view Sagittal view Coronal view
*Source: RSNA News – August 2004 Patients and Physicians Uninformed
About CT Risks.
Accessed 8/28/04
**Source: Studies Find Radiation Doses From CT Scans Often Too High
For Children. http://imaginis.com/ct-scan/news/news1.26.01.asp. Accessed
Radiation Exposure During CT Scans
■ CT studies expose the patient to significantly more radiation
than conventional x-rays. For example, a chest CT can expose
the patient to 100 times more radiation than a plain x-ray.*
■ Pregnant women should not undergo CT scanning because of
potential damage to the fetus.
■ Lead shields are used to protect reproductive organs from
radiation exposure.
■ Pediatric patients are often exposed to much higher doses than
necessary because default settings are intended for adults.**
◆ Excessive exposure to radiation during childhood can lead to
cancer later in life.
◆ Scanning protocols should be adjusted for each child’s weight
and body type.
◆ Health care providers should weigh the risks and benefits of
using CT scans in children, especially when multiple CT scans
are anticipated.
CT Scans with Contrast Media
■ CT scan studies may be enhanced with contrast agents.
■ CT contrast agents are used to make organs, blood vessels,
and/or tissue types appear whiter to better show neoplasm,
disease, or injury. See next page for overview of contrast and
refer to pages 78-82 in Tab 3 for a complete discussion of
contrast media, its uses, and risks.
■ Contrast can be administered intravenously, orally, rectally, or by
inhalation, which is called Xenon CT (for the name of the gas
inhaled and is used for lung and brain imaging).
■ In studies of pelvic organs, patients may receive IV, oral, and
rectal contrast.
■ Associated with greater risk of reaction than other routes.
■ Given to visualize blood vessels and tissues such as brain,
spine, liver, and kidneys.
■ Administered by loading into a power-assisted injector, which
automatically administers the contrast.
■ Total volume of contrast injected ranges from 75–150 mL.
■ Patients may experience a warm feeling and a metallic taste
when contrast is injected, which is harmless.
■ Patients may also experience mild itching, hives, nausea,
vomiting, or dizziness, which can be treated with
■ Other reactions include cardiovascular, nephropathic, or
delayed responses or severe anaphylactoid responses.
■ Studies using IV contrast can only be performed after
obtaining informed consent.
■ Assess renal function studies. Report elevations in
BUN/creatinine to physician and radiology staff.
■ Determine if patient takes metformin (Glucophage), which
must be withheld for 48 hr after administration of IV contrast.
■ Barium and Gastrografin are the contrast agents used to
enhance images of the abdomen and pelvis.
■ Barium is the most commonly used agent. It has a milk
shake– like consistency and is flavored to enhance palatability.
■ Gastrografin has the consistency of water. It is an iodinated
contrast medium (i.e., it contains iodine).
■ Patient preparation varies but usually involves restriction of
food and fluids for several hours prior to testing.
■ Patients usually drink 1000–1500 mL of contrast.
■ Barium or Gastrografin is also administered rectally when CT
scanning the large intestines or pelvic organs.
■ It is administered in the radiology department.
■ After the study is complete, the contrast is drained out of the
large intestine.
■ Preparation involves restricting foods and fluids and taking
laxatives and/or cleansing enemas before testing.
Patient Preparation for CT Scan
■ Tell the patient that he or she should:
◆ Wear comfortable, loose-fitting clothing if an outpatient.
◆ Remove clothing, jewelry, or anything else that might
interfere with imaging (belts, earrings, bra, glasses,
dentures, hairpins, clothing with zippers and snaps). If
jewelry has psychological or spiritual significance for the
patient, it usually can be held by the patient or moved to a
part the body not under examination.
◆ Inform the physician of any medications that are being
taken, both prescription and nonprescription.
◆ Inform the physician if pregnant, diabetic, or allergic to any
foods or drugs.
◆ Inform the physician about previous reactions to contrast.
■ Explain to the patient that he or she will:
◆ Be positioned on a narrow table that slides into the scanner.
◆ Be monitored by a technologist and a radiologist who will
be directing the study from an adjacent room (where the
monitor and computer are).
◆ Be able to communicate with the technologist at all times
via an intercom.
◆ Experience no pain from the study, although positioning
might feel a little awkward.
◆ Have an IV started if contrast will be given.
◆ Be asked to hold his or her breath and lie very still for up to
30 sec.
■ On rare occasions, the contrast may cause a life-threatening
anaphylactoid reaction manifested by laryngeal edema,
shortness of breath, and hypotension.  Tell the patient to
alert the technologist via the intercom if he or she has trouble
breathing. Tell the patient if this occurs, the exam will be
stopped and medication given.
■ If scheduled for abdominal films, determine if the patient has
had a barium contrast study or taken medications containing
bismuth in the previous 4 days. (Films will need to be
postponed until all contrast is excreted.)
■ After the CT images are reviewed, the patient will be released
from the imaging department or center.
Abdominal/Pelvic CT
Computed x-ray of the abdomen and or pelvic organs, usually with
oral contrast and IV contrast and sometimes with rectal contrast
as well. Used for looking at solid organs, such as the liver,
pancreas, spleen, kidneys, adrenal glands, and pelvic organs and
for evaluating the abdominal aorta and vena cava. Also used to
assess lymph nodes in the abdomen. Less useful for evaluating
the stomach and intestines, although the CT scan can provide
some information about these structures as well. Informed
consent usually required. Potential complications: severe adverse
reaction to contrast.
■ Assess abdominal/pelvic pain or suspected liver, kidney, or
gallbladder disease.
■ Evaluate abdominal trauma.
■ Assess signs of inflammation or infection inside the abdomen.
■ Assess for cancer; stage or monitor tumors during therapy.
Before the procedure begins, the patient will drink the oral contrast
and, if IV contrast is to be given, will have an IV placed. The
patient then lies on the CT table. The technologist will help
position the patient’s body, if necessary, with pillows. The table
will be advanced slowly into the gantry (the ring-shaped CT
scanner) in millimeters as the images are taken. The technologist
will tell the patient when to hold his or her breath, and will also
control the position and advancement of the table. The IV contrast
may be administered before or during the test.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about previous reactions to contrast or other risk
factors for adverse reaction to contrast (see page 79).
■ Unless no IV contrast will be given, the patient should be well
hydrated and should increase fluid intake the day before the test.
Check BUN; if elevated, notify radiologist.
■ Ascertain that patients on metformin (Glucophage) have
withheld the medication the day of the test.
■ Tell the patient the test is painless.
■ Oral contrast preparation may vary, but generally the patient will be
asked to drink three cups of oral contrast over a 30-min period 90
min before the CT appointment. The patient then will be given more
contrast to drink in the radiology department.
■ Check with the radiology department about restriction of food and
fluids. Some departments ask that the patient remain NPO except
for the contrast and medications while others may allow the patient
to eat lightly (juice and crackers) after the initial few cups of oral
contrast have been consumed at home.
■ The patient should void immediately before the test.
■ Inform the patient that the test will take 5–30 min.
■ When the exam is over, the technologist will check the images while
the patient waits. If no more images are needed, the patient will be
discharged from the radiology department.
■ If IV contrast is given, provide the patient with and encourage
intake of oral fluids to help excrete the contrast.
■ If oral or rectal barium was given, tell the patient that stools may
appear light-colored and to inform a health care provider if
■ Monitor for reaction to IV contrast.
CT scan of abdomen. Arrows point to adrenal gland. a aorta, v  vena
cava, p  pancreas, k  kidney, L  liver, s  spleen.
Angiogram, CT (CTA)
X-ray with contrast to visualize arterial blood flow of the brain,
lungs, kidneys, or extremities. CT angiography is much less
invasive than traditional arteriography, which involves arterial
puncture and threading a catheter through the artery. In CTA,
iodinated contrast is quickly injected into a peripheral vein
while numerous and very thin “slices” are imaged. Informed
consent may be required. Potential complications: severe
adverse reaction to contrast.
■ Detect atherosclerotic disease.
■ Evaluate for pulmonary embolism.
■ Assess blood flow in the renal, pelvic, or carotid arteries.
■ Identify aneurysms.
■ Identify aortic dissection.
■ Identify cerebral arteriovenous malformation.
■ Evaluate stent functionality.
■ Evaluate trauma patients for arterial damage.
The patient is positioned on the CT table with the body part to
be examined placed inside the opening. First, a test image and
small dose of contrast will be taken to determine optimal
positioning and timing. Next, the contrast is loaded into an
automatic injector and the contrast is administered quickly
while the area is scanned.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about previous reactions to contrast or other risk
factors for adverse reaction to contrast (see page 79).
■ The patient should be well-hydrated and should increase fluid
intake the day before the test.
■ Check BUN; if elevated, notify radiologist.
■ Ascertain that patients on metformin (Glucophage) have
withheld the medication the day of the test.
■ Tell the patient the test is painless and will take 10–20 min.
■ When the exam is over, the technologist will check the images
while the patient waits. If no more images are needed, the
patient will be discharged from the radiology department.
■ Provide the patient with and encourage intake of oral fluids to
help excrete the contrast.
■ Monitor for reaction to IV contrast.
Brain CT
Computed x-ray of the brain, usually with contrast. Images show
slices of brain as though viewed from the top of the head. A
xenon CT or a perfusion CT scan can reveal cerebral blood flow.
Helical or spiral CT scans result in three-dimensional images
that aid greatly in localizing brain tumors. Informed consent
may be required. Potential complications: severe adverse
reaction to contrast.
■ Assess patients with head trauma for bleeding, brain damage,
or skull fractures.
■ Assess patients with stroke symptoms.
■ Evaluate sinuses.
■ Evaluate facial injuries and as an adjunct to planning for
surgical reconstruction.
■ Assess patients with neurologic symptoms including severe
headache or change in mental status.
■ Detect aneuysms, infection, tumor, or structural defects.
■ Plan radiation therapy for brain cancer.
■ Guide needle biopsies of the brain.
The patient lies supine on the CT table and the head is immo-bilized in a brace. An IV will be started if contrast will be used.
The table is advanced into the scanner and a series of pictures
are taken at different intervals and at varying levels over the
head. The images are displayed on a viewing monitor and then
recorded on film. IV contrast is then injected and a second
series of pictures is taken.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about previous reactions to contrast or other risk factors
for adverse reaction to contrast (see page 79).
■ Unless IV contrast will not be given, the patient should be well
hydrated and should increase fluid intake the day before the test.
■ Check BUN; if elevated, notify radiologist.
■ Ascertain that patients on metformin (Glucophage) have withheld the
medication the day of the test.
■ Tell the patient the test is painless and will take 10–20 min without
contrast or up to 40 min with contrast because scans are taken before
and after contrast.
■ When the exam is over, the technologist will check the images while
the patient waits. If no more images are needed, the patient will be
discharged from the radiology department.
■ If IV contrast was given, provide the patient with and encourage intake
of oral fluids to help excrete the contrast.
■ Monitor for reaction to IV contrast.
CT showing intracerebral hemorrhage within the left parietal lobe.
New Technology: CT Cerebral Perfusion Imaging
■ Perfusion CT scanning is a relatively new technique that can
be used to provide qualitative and quantitative information
about the blood flow in the brain.
■ How it works: Using traditional CT scanning methods and
special software, the patient’s brain is scanned every few
seconds before, during, and after the administration of IV
contrast. The data obtained are then analyzed to determine
cerebral blood volume (how much blood is in the brain), the
mean transit time of the blood through the cerebral
capillaries, and the cerebral blood flow. Areas of interest can
be isolated; for example, if the physician wants to know
adequacy of blood flow from a specific artery.
◆ Can be performed using standard CT scanners.
◆ More widely available and less expensive than MRI.
◆ Less invasive than CT angiography.
◆ Uses a relatively small amount of contrast agent.
◆ Other brain-scanning techniques such as PET, SPECT, or
xenon CT require special equipment not found in many
hospitals, cost more, or are more difficult for patients.
◆ Assess blood flow prior to carotid surgery.
◆ Assess stroke risk.
◆ Assess ischemic damage and potential benefit of tPA
◆ Assess cerebrovascular reserve (the degree to which the
brain blood flow system is stressed) by administering
acetazolamide to dilate blood vessels and maximize
flow. Some patients’ vessels don’t dilate in response to
acetazolamide, indicating they already are maximally
dilated and letting as much blood through as possible.
◆ Potentially can be used to map brain tumor growth and
Source: Hoeffner EG et al. Cerebral perfusion CT: technique and clinical
applications. Radiology.2004; 231: 632–644.
Applications Advantages
Chest CT
Computed x-ray of the chest, usually with contrast. A spiral CT
gives better quality images in less time (20 sec), which is an
important consideration for children, elderly, or critically ill
patients who cannot hold their breath for a long time. Informed
consent may be required. Potential complications: severe adverse
reaction to contrast.
■ Follow-up to abnormal or inconclusive conventional chest x-rays.
■ Evaluate signs and symptoms of disease of the chest.
■ Detect and evaluate primary tumors in the lung and
mediastinum or metastatic tumors from other parts of the body.
■ Assess tumor response to treatment.
■ Guide needle biopsy to the lung.
■ Assess for pneumonia, tuberculosis, emphysema, bronchiectasis,
and diffuse interstitial lung disease.
■ Assess for inflammation or other diseases of the pleura.
■ Evaluate patients with chest injury to assess injury to organs,
bones (including the spinal column), and major blood vessels.
■ Evaluate suspected aneurysm.
■ Detect pulmonary emboli (see CT Angiogram [CTA]).
The patient is positioned on the table and the table is advanced into
the scanner while a series of pictures are taken. The images are
displayed on a viewing monitor and then recorded on film. If IV
contrast is to be used, the technologist injects the contrast and a
second set of pictures is taken.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about previous reactions to contrast or other risk
factors for adverse reaction to contrast (see page 79).
■ If IV contrast will be given, the patient should be well hydrated
and should increase fluid intake the day before the test.
■ Check BUN; if elevated, notify radiologist.
■ If IV contrast will be used, ascertain that patients on metformin
(Glucophage) have withheld the medication the day of the test.
■ Tell the patient the test is painless and will take 15–30 min.
■ When the exam is over, the technologist will check the images
while the patient waits. If no more images are needed, the
patient will be discharged from the radiology department.
■ If IV contrast was given, provide the patient with and encourage
intake of oral fluids to help excrete the contrast.
■ Monitor for reaction to IV contrast.
Skeletal CT (Bones or Joints)
Computed x-ray of the bones or joints provides more detailed
information than standard x-rays. Contrast material may be given
with the CT scan to help define blood vessels or soft tissue areas.
Informed consent may be required if IV contrast is given. Potential
complications: severe reaction to contrast.
■ Assess bones, cartilage, muscles, tendons, and joints for
damage, lesions, fractures, or other abnormalities.
■ Detect primary or metastatic tumors.
■ Detect hidden fractures or bone infection (osteomyelitis).
■ Assess difficult to evaluate joints such as the emporomandibular
joint, sternoclavicular joint, or sacroiliac joint.
The patient is positioned on the CT table. An IV is started if contrast
is to be given. The table is then advanced into the scanner and the
tomograms are taken.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about previous reactions to contrast or other risk
factors for adverse reaction to contrast (see page 79).
■ If IV contrast will be given, the patient should be well hydrated
and should increase fluid intake the day before the test.
■ Check BUN; if elevated, notify radiologist.
■ If IV contrast will be used, ascertain that patients on metformin
(Glucophage) have withheld the medication the day of the test.
■ Tell the patient the test is painless and will take 15–30 min.
■ When the exam is over, the technologist will check the images
while the patient waits. If no more images are needed, the
patient will be discharged from the radiology department.
■ If IV contrast was given, provide the patient with and
encourage intake of oral fluids to help excrete the contrast.
■ Monitor for reaction to IV contrast.
Spinal CT
Computed x-ray of the spine, usually with contrast IV or
intrathecal contrast. A spinal CT gives better quality images in
less time (20 sec), which is an important consideration for
children, elderly, or critically ill patients who cannot hold their
breath for a long time. Spinal CT does not always show enough
detail to properly assess the spinal cord. For this reason, MRI
imaging is preferred. Informed consent may be required.
Potential complications: severe adverse reaction to contrast.
■ Detect spinal damage in trauma patients.
■ Detect primary or metastatic tumors in the vertebral column.
■ Identify spinal stenosis (narrowing of the spinal canal),
vertebral fracture, infection, or degenerative disease such as
■ Guiding diagnostic procedures such as the biopsy or
aspiration of fluid from a localized infection (abscess).
The patient lies on his or her back on the CT table. An IV is
started. Although pictures are taken initially without contrast,
intrathecal or IV contrast is administered after the first set of
pictures is taken. For intrathecal injection, the patient lies on his
or her stomach or side. The injection is usually given in the
lumbar spine but may occasionally be injected into the cervical
spine. After skin preparation, the needle is inserted. Under
fluoroscopic CT guidance, the physician injects the contrast and
the needle is removed.
The patient is asked to move into different positions, or the table
may be tilted at different angles to move the contrast material
into the areas of interest. The table is then advanced into the
scanner and the tomograms are taken.
■ See General Pretest Patient Education in Tools Tab.
■ Ask patient about previous reactions to contrast or other risk
factors for adverse reaction to contrast (see page 79).
■ Unless IV contrast will not be given, the patient should be well
hydrated and should increase fluid intake the day before the
■ Check BUN; if elevated, notify radiologist.
■ If IV contrast will be used, ascertain that patients on
metformin (Glucophage) have withheld the medication the
day of the test.
■ Tell the patient the test is painless and will take 15–30 min.
■ When the exam is over, the technologist will check the images
while the patient waits. If no more images are needed, the
patient will be discharged from the radiology department.
■ If IV contrast was given, provide the patient with and
encourage intake of oral fluids to help excrete the contrast.
■ For patients who have had intrathecal puncture, assess VS,
sensation, and mobility in lower extremities and general
neurologic status including headache, irritability, or seizure
■ Monitor for reaction to IV contrast.
Body CT Scan, Whole
Computed x-ray of the entire body without contrast. Whole body
computed tomography (WBCT) is sometimes advocated as a
screening tool, although professional organizations and the FDA
generally state that no evidence exists to support the use of CT
scanning on asymptomatic individuals (i.e., as a screening tool). In
some imaging centers, patients can obtain a whole body scan
without a physician’s order. Informed consent is not usually
■ Screen for disease.
The procedure is similar to all other CT scans, except that contrast
is not given.
■ Pretest preparation is primarily educational; for example,
explaining what the machine looks like, the way to communicate
with the technologist, positioning, etc.
■ The patient undergoing elective WBCT should be told the
limitations of the study, the risks of radiation exposure, and the
possibility that benign conditions, formerly unsuspected, will
require follow-up interventions to definitively rule out pathologic
processes. These interventions could subject the patient to risks
he or she otherwise would not have encountered.
■ Follow-up may be limited to noninvasive testing or may involve
invasive procedures and the risks of anesthesia. Even other
radiologic exams carry risks of radiation exposure and potential
allergic reaction to injected contrast material.
■ Posttest care is also primarily educational involving explaining
when test results will be available.
■ The patient who has undergone a WBCT for asymptomatic
screening should be reminded that normal findings carry the
possibility of inaccuracy and false reassurance and that
suspicious findings will require follow-up.
Overview of MRI
■ MRI is a noninvasive imaging technology that gives detailed
pictures of internal structures.
■ MRI is used to evaluate:
◆ Head trauma (assess for bleeding or swelling).
◆ Neurologic symptoms suggestive of cerebral aneurysm,
stroke, tumor, and suspected spinal cord lesion or injury.
◆ Cardiac or major blood vessel disease (vena cava
obstruction, renal vein thrombosis, renal arterial
obstruction, portal vein obstruction, aneurysms).
◆ Renal disease (hydronephrosis, glomerulonephritis, acute
tubular necrosis).
◆ Cancer of the pancreas, adrenal glands, and gallbladder.
◆ Biliary disease, lymphadenopathy, and staging of prostate,
uterine, or bladder cancer.
◆ Musculoskeletal disorders including problems with joints,
soft tissues, or bones.
■ MRI generally is not helpful in evaluating small and large
bowel function.
■ MRI scans produce very detailed images of body structures.
The images look similar to CT scan images, but MRI scans are
done without using ionizing radiation. Ionizing radiation,
which is used in conventional x-rays and CT scans, is radiation
with enough energy to completely remove an electron from its
orbit. Ionization can be destructive to living tissue and
increases the risk of developing cancer.
■ In addition to producing images of structures, MRI is also used
to “see” the physiology of the body through techniques such
as functional MRI (fMRI). For example, fMRI can show which
parts of the brain are functioning during various activities. This
is accomplished by asking the patient to perform certain tasks
(tapping fingers, answering simple questions) during imaging.
■ MR angiography (MRA) produces 3-D reconstructions of blood
vessels, is noninvasive, and doesn’t require contrast.
■ MR spectroscopy (MRS) reveals the biochemistry of specific
organs or tissues.
How MRI Works
■ The body contains millions of hydrogen atoms in all types of
tissue. MRI is based on the fact that hydrogen atoms found
throughout the body in water can be affected by a magnetic
field. The net result is that an MRI image shows differences in
the water content and distribution in various body tissues
■ The MRI machine looks like a large cylinder with a table that
can advance into the bore, or opening, of the cylinder. The
cylinder contains the powerful magnet.
■ After proper preparation and positioning, the patient is placed
in the MRI machine and into the strong electromagnetic field
generated by the magnet.
■ In response to this magnetic pull, the hydrogen atoms in the
body align with the magnetic field, either in the same
direction or opposite to the direction of the field.
■ A powerful radio signal is then sent through the patient’s
body at the desired level (or slice). This results in the
hydrogen atoms being raised to a higher state of energy.
■ When the radio signal is turned off, the hydrogen atoms
return to their original energy state and the extra energy, or
resonance, is released in the form of radio waves.
■ This resonance is picked up by radio receivers in the MRI
machine and transmitted to a computer. These energy
differences end up appearing as different shades of gray on
the MRI image.
■ Through a series of complex calculations, the computer
constructs an image derived from the magnetic resonance
and displays it on a screen. It is then photographed and
recorded on x-ray film.
■ Different tissues resonate at different frequencies, which is the
basis for how the detailed images are produced.
■ Current MRI machines generate these images as 3-D
projections. A 3-D MRI image can be “sliced” and examined in
detail, which has been described as “virtual” exploratory
Safety Issues Associated with MRI
Several injuries and a few deaths have occurred during MRI
because of the powerful magnets used. Not only are the
magnets capable of attracting metal objects quite a distance
from the magnet, but the magnetic field also interferes with the
operation of certain devices. Overall, five hazards associated
with MRI have been identified:
■ Flying projectiles—metallic objects are forcefully pulled by the
magnet, becoming airborne and hurtling toward the opening
of the MRI machine. Several patients have been killed or
injured by oxygen tanks, scissors, IV poles, traction weights,
stethoscopes, and other magnetic objects, which can reach
speeds of up to 40 miles per hour.
■ Twisting or movement of metallic implants such as aneurysm
clips in response to the strong magnetic fields of the MR
■ Burns—anything with metal in it can become hot and cause
burns. Burns from various sources including contact with an
electrically conductive cable, tattoos heating up due to the
iron oxide content, ECG or pulse oximeter leads conducting
currents, and patient contact with the magnet bore have been
■ Malfunction of devices, including PCA pumps, ventilators, and
pacemakers, leading to serious patient harm or death.
■ Undetected artifact from various sources leading to change in
MRI image and possible misdiagnosis.
MRI is contraindicated in the presence of the following patient
conditions or treatment modalities:
◆ Cardiac pacemaker.
◆ Implanted cardiac defibrillator.
◆ Aneurysm clips.
◆ Carotid artery vascular clamp.
◆ Neurostimulator.
◆ Insulin or infusion pump.
◆ Implanted drug infusion device.
◆ Bone growth/fusion stimulator.
◆ Cochlear or ear implant.
◆ IUD or diaphragm.
MRI Contrast
■ Contrast is used in MR studies to help differentiate diseased
tissue from healthy tissue.
■ In conventional x-rays and CT scanning, contrast media
weaken x-rays as they pass through the body. In MRI, contrast
works by altering the time it takes for hydrogen atoms to
return to their original energy state. Because the time factor is
changed, the contrast-enhanced tissues send out different
signal intensities, which cause them to appear much brighter
on the final image.
■ Contrast also enables detection of smaller-sized tissue
changes. For example, tumors 1–2 cm in size will show up
fairly clearly without contrast, whereas contrast-enhanced
studies may reveal even smaller tumors.
■ Most MRI contrast media contain gadolinium, a heavy metal
(chemical symbol Gd). Other agents, those with organ
specificity, are also available.
■ MRI contrast agents are administered intravenously by the
MRI technician during the test. Unlike iodinated contrast
agents, patients do not experience any flushing, itching, or
metallic taste when MRI contrast is administered.
■ Although reactions to MRI contrast are much rarer than
reactions to iodinated contrast agents, the possibility of a
reaction, including serious, anaphylactoid or cardiovascular
reactions, should always be considered, especially in those
patients with a known clinical hypersensitivity, a history of
asthma, or other allergic respiratory disorders.
■ Since contrast is largely excreted by the kidneys, renal
function should be monitored when patients with impaired
renal function receive contrast.
■ Patient with sickle cell anemia and other hemoglobin
disorders may have an increased risk of vaso-occlusive
Pretest Patient Preparation for MRI
■ Tell the patient that he or she will change into a hospital gown.
■ There are no food or fluid restrictions prior to MRI. Occasionally, the
patient may be asked to restrict food or fluids.
■ Explain that the patient will have to remove jewelry, watch, hairpins
or hair clips, keys, coins, wallet, credit cards, eyeglasses, hearing
aid, removable dental work, belts and buckles, or other objects
suspected of containing metal.
■ The patient must be thoroughly screened for internal metallic
objects. Ask the patient about prosthetic valves or joints, implanted
infusion devices, shrapnel, bone screws, metal plates, etc. All
imaging centers will have a screening form for this purpose that
must be completed.
■ Explain that the technologist will start an IV if contrast is used.
Procedure for MRI
■ After positioning the patient on the table, the technologist places an
apparatus called a surface coil (a special radio antenna) around the
area of interest.
■ The table is advanced into MR gantry (opening).
■ The technologist will leave the room, but the patient can
communicate with the technologist via the intercom.
■ A mild sedative can be given prior to the MRI scan to help control
anxiety and claustrophobia.
■ The patient will hear knocking noises as the MR sequences are run.
Most scans require two to six different sequences, each lasting 2–15
■ The patient must lie completely still during scanning.
■ The MRI scanning time ranges from 30 to 90 min.
Posttest Care After MRI
■ After the study is complete, the patient will be asked to wait until
the images are reviewed. Once it is determined that the images are
adequate, the patient can leave.
■ Tell the patient when the results will be available and whom he or
she should contact with questions.
■ No physical posttest care is required.
◆ Distinguish an adrenal adenoma from a
metastatic lesion.
◆ Pheochromocytomas and other
◆ Identify biliary system in patients who
cannot tolerate endoscopic retrograde
cholangiopancreatography (ERCP).
◆ Retained gallstones, recurrent
choledocholithiasis, strictures, biliary and
pancreatic neoplasms, and chronic
pancreatitis all may be assessed, as can
fluid collections or aneurysms.
◆ Tumor, infection, inflammation, trauma,
stroke, multiple sclerosis, optic or auditory
nerve dysfunction, change in mental
status, headaches, and symptoms
associated with vascular occlusion.
◆ In functional MRI (fMRI), assess the part of
the brain controlling thought, speech,
movement, or sensation. This is helpful in
planning surgical or radiation treatment
for brain lesions.
◆ Lung masses.
◆ Follow-up to other diagnostic study.
◆ Assess for abnormal lymph nodes.
◆ Stage tumors.
(Continued on following page)
Adrenal, Biliary, Brain, Chest, Kidney, Liver,
Musculoskeletal, Spine, and Vascular  System
MRI Scans
For all the following MRI scans, refer to Pretest Preparation,
Procedure, and Posttest Care on the preceding page and
General Pretest Patient Education in Tools section.
MRI Scans
MRI Ordered Indications/Comments
Adrenal glands
Biliary system
MRI Ordered Indications/Comments
Vascular system
◆ Characterize mass found on other study,
renal imaging for patients who can’t take
x-ray contrast, and assess patency of renal
veins or inferior vena cava.
◆ Assess for tumor thrombus in renal cell
◆ Ultrasound and CT are the primary
imaging studies for the liver but MRI,
using liver-specific contrast, can be
used to diagnose atypical liver
lesions, cirrhosis, tumors, and
hemangiomas and to assess for portal vein
◆ Internal derangement of the knee
(meniscal injuries, ligament tears).
◆ Shoulder injuries (rotator cuff tears,
◆ Hip pain (osteoporosis, osteoarthritis,
avascular necrosis).
◆ Assess pain, swelling, and deformity in
any joint including temporomandibular
◆ Disc disease, spinal stenosis, tumors,
infection, inflammation, and multiple
◆ Assess all areas of the spine—cervical,
thoracic, lumbar.
◆ Noninvasive assessment of many vascular
◆ Circle of Willis, carotid arteries are the
most common sites.
◆ Assess thoracic and abdominal aortic
aneurysms, renal arteries, and lower
extremity arteries and coarctation.
◆ Presence and extent of renal artery
Example of an MRI Image
MRI of the cervical spine, sagittal view. Note cerebellum (A), spinal cord
(B), marrow of C2 vertebral body (C), and dense intervertebral disc of
New Technology: Cardiac Magnetic Resonance Imaging
MRI has been used successfully to image all areas of the body,
including the heart and the vascular system. However, due to
the complexities involved in imaging the beating heart,
difficulties that are magnified when trying to image small
coronary arteries, MRI as an aid to diagnosing coronary artery
disease or heart attack is still an unrealized goal.
Nonetheless, research into enhancing the use of MRI in the
diagnosis of cardiac disease, especially to diagnose it before
symptoms develop, continues in many university settings.
Potential Uses of Cardiac MRI
■ Diagnose heart attack in patients with chest pain.
■ Diagnose coronary artery disease using a technique called
“black-blood” MRI (in the resulting image, the blood appears
black and the artery wall appears white).
■ Identify plaques that are vulnerable to rupture.
■ Assess angioplasty sites for restenosis.
■ Assess the microvascular circulation of the heart.
■ Replace fluoroscopy to guide procedures such as angioplasty.
Potential Advantages of Cardiac MRI
■ Replace multiple other tests including cardiac catheterization,
echocardiogram, MUGA scan, and thallium scan.
■ Does not involve exposure to ionizing radiation.
■ Does not expose the patient to iodinated contrast agents.
■ Does not expose the patient to the risks associated with
arterial puncture and cannulation.
Disadvantages of Cardiac MRI
■ Because metal objects cannot be in the MRI scanning room,
patients who require cardiac monitoring or who have stents,
staples, or a pacemeaker will be ineligible for the test.
■ Other known disadvantages such as expense and some
patients’ inability to tolerate the enclosed space of the MRI.
Source: Cardiac MRI – Ready for prime time? Heart Disease/
Cardiology, Richard N. Fogoros, M.D. http://heartdisease.about.com/
library/weekly/aa031201a.htm accessed 8/1/04
Overview of Ultrasound Imaging
■ An ultrasound study, also called a sonogram, is a noninvasive
diagnostic procedure that uses sound waves to create gray-scale images of internal structures. The high-pitched sound
waves cannot be heard by the human ear.
■ How it works:
◆ Ultrasound uses high frequency sound waves to obtain
images of internal structures.
◆ The ultrasound is produced by the transducer, which is
attached to the ultrasound equipment.
◆ The transducer is pressed against the skin overlying the
structure to be studied. For some studies, the transducer is
placed internally.
◆ The transducer sends a pulse of ultrasound waves into the
tissues. When the sound waves hit a boundary between
tissues, the ultrasound waves bounce back as a series of
echoes and are picked up by the transducer, amplified, and
displayed on the monitor.
◆ Using the time it takes for sound to travel through tissue
and the time it takes for the echoes to return, the machine
calculates the distance from the probe to the tissue or
◆ These distances and intensities of the echoes are displayed
on the screen.
■ It is used to evaluate the shape and position of organs and
tissues and to detect masses, edema, stones, and
displacement of tissue. In obstetrics, ultrasound is used to
evaluate fetal development and well-being.
■ Ultrasound is also used to guide biopsies.
■ Tissues that strongly reflect ultrasound are called hyperechoic.
■ Tissues that reflect ultrasound poorly are called hypoechoic.
■ Fluid, which does not reflect sound, is anechoic.
■ Echocardiography is ultrasound of the heart. It is used to eva-luate cardiac chamber size, wall thickness, wall motion, valve
configuration and motion, and the proximal great vessels.
■ Vascular ultrasonography is ultrasound of blood vessels.
To recorder
Blood flow RBCs
Skin and
■ Conventional ultrasonography is ultrasound of organs other
than the heart such as:
◆ Liver, gallbladder, and spleen.
◆ Kidneys and bladder.
◆ Prostate, uterus, ovaries, and breasts.
◆ Musculoskeletal structures.
■ 3-D ultrasound uses special software and the 2-Dl images
obtained from ultrasound to construct 3-D images of internal
■ Doppler ultrasound is a technique used to determine speed of
blood flow through arteries and veins by converting the
sound waves into audible sounds or line graphs. Doppler
colorflow imaging, harmonic Doppler, and spectral Doppler
are different modalities that enhance images and provide
more information.
Doppler ultrasound device to detect bllod flow velocity.
Pretest Preparation for Ultrasound Tests
■ Many ultrasound studies require no food or fluid restrictions
but some preparation may be indicated.
■ Pelvic ultrasounds usually require a full bladder, so the patient
may be asked to drink several glasses of water and not void
before the test.
■ Some abdominal ultrasounds require that the patient eat a
low- fat meal or restrict intake for a few hours before the test.
Procedure for Ultrasound Tests
■ The patient changes into a hospital gown and then is
positioned on the exam table.
■ The appropriate body area is exposed for examination.
■ Acoustic conducting gel is applied on the skin overlying the
structure to be examined.
■ The sonographer then applies the transducer gently to the
area, moving it as needed to obtain the images.
■ After the exam is completed, the gel is removed.
■ Most tests take approximately 30 min.
Posttest Care After Ultrasound Tests
■ Most studies do not require specific posttest care.
■ Patients having a transesophageal echocardiogram or a
dobutamine stress echocardiogram will require monitoring for
a short time after the study.
■ All patients require information after a study is completed,
including when results will be available and whom to call for
information or to report side effects or complications.
■ An echocardiogram (“echo”) is an ultrasound of the heart. In
echocardiography, the high-frequency sound waves bounce off
cardiac structures to provide information about the size, shape,
and position of the heart, the thickness of the walls of the heart,
and the function of heart valves, atria, and ventricles.
■ Doppler echocardiography is performed with an echo to
determine the direction and velocity of blood flow in the heart.
■ There are several types of echocardiograms, which will be
described in the following pages:
1. Transthoracic Echocardiogram
2. Transesophageal Echocardiogram (TEE)
3. Dobutamine Stress Echocardiogram
New Technology: Echocardiogram Contrast
■ The use of contrast in echocardiography is not new; however,
new advancements in ultrasound techniques and contrast agents
have improved the quality of contrast ultrasound studies.
■ Obtaining good echocardiographic images is often difficult in the
patient who is obese, has a barrel chest from COPD or other
chest deformity, is in ICU, or is on a respirator. These technically
difficult studies can be enhanced with contrast.
■ Ultrasound contrast is made of gas-filled microbubbles smaller
than a red blood cell. The microbubbles are encapsulated in a
shell of albumin, phospholipid, or other substance, which helps
prevent them from being destroyed in the high–blood flow
circulation. The bubbles improve the quality of the images.
■ Ultrasound contrast agents (USCA) travel into the right heart
after IV injection, into the pulmonary circulation, and then into
the left heart.
■ Echocardiography with contrast is most commonly used for the
evaluation of left ventricle function.
■ The new contrast agents are generally well tolerated, but some
patients may experience allergic reactions to contrast with
Transthoracic Echocardiogram
Ultrasound with or without contrast. Informed consent generally
not required. Potential complication: reaction to ultrasound
■ Evaluate cardiac structures, function, and blood flow.
■ Evaluate ejection fraction (EF), a measure of the heart’s
pumping ability (reference ranges: males: 63–77% females:
■ Assess for thinning or thickening of heart walls and dilated
atria or ventricles.
■ Assess for abnormal wall motion or scar tissue.
■ Assess for stenosed or leaking valves and valvular
■ Assess for atrial-septal defect, aortic dilation or dissection.
■ Assess for pericardial effusion, thrombi, tumors, masses.
The patient wears a hospital gown and lies on the exam table.
ECG leads are attached and the sonographer applies acoustic
gel to the transducer and the patient’s skin. The heart is
assessed from several different views with the patient lying on
his or her back or left side.
■ See General Pretest Preparation in Tools Tab.
■ There is no need to restrict food or fluids or withhold
■ Tell the patient the test is painless, without risk, and takes
approximately 1 hour or up to 90 min if a Doppler Echo is
■ Echocardiography does not require any specific follow-up
■ Tell the patient the test results will be available in 24–48 hr.
Transesophageal Echocardiogram (TEE)
Ultrasound using an internal transducer. Since the esophagus is
closer to (lies behind) the heart, the TEE can provide better images.
Informed consent required. Potential complications: esophageal
perforation or bleeding, complications from IV sedation.
■ Evaluate cardiac structures, function, and blood flow. May be
done during surgery.
■ Assess for thinning or thickening of heart walls, dilated atria or
ventricles, abnormal wall motion, scar tissue, stenosed or
leaking valves, valvular vegetations, atrial-septal defect, aortic
dilation or dissection, pericardial effusion, thrombi, tumors, and
The patient lies on his or her left side on the exam table. An IV isl
be started and monitoring apparatus including ECG leads, blood
pressure cuff, and pulse oximetry are placed on the patient. The
patient receives IV sedation and the pharynx is sprayed with a
local anesthetic.
The flexible transducer probe is advanced into the pharynx and into
the esophagus. The patient assists placement by swallowing. The
transducer surface is manipulated into position by the external
controls and the heart is studied from various angles. Ultrasound
contrast (USCA) may be administered to improve image quality.
The transducer is removed once all images have been obtained.
■ The patient should not eat or drink anything after midnight the
night before the test.
■ Medications may be taken with a small sip of water.
■ Because the patient will be NPO, oral hypoglycemic agents and
insulins should be held until after the test. Consult with primary
care physician.
■ Tell the patient that his or her dentures will have to be removed.
■ Tell the patient the test lasts approximately 45 min, but to be
prepared to spend approximately 2 hr in the exam area.
■ After the procedure, the patient will remain in the procedure
room until he or she is fully awake and alert.
■ The patient’s blood pressure, respirations, and pulse will be
monitored until stable.
■ The patient cannot eat or drink for 2 hr after the test, and the
gag reflex should be assessed before taking foods or fluids.
■ Once the gag reflex has returned, the patient may eat soft
foods but should avoid hot liquids for 24 hr.
■ Patients discharged to home after the test must have another
person available to drive them.
Transesophageal echocardiogram compared to transthoracic
Dobutamine Stress Echocardiogram (DSE)
See Transthoracic Echocardiogram for description of the pro-cedure. Dobutamine stress echocardiogram evaluates cardiac
function before and after IV administration of dobutamine.
Informed consent required. Potential complications:
dobutamine-induced side effects including hypertension,
dysrhythmias, lightheadedness, chest pain, nausea, dyspnea.
■ The test is ordered to evaluate coronary artery disease in
patients unable to exercise on a treadmill. Dobutamine
“stresses” the heart, increasing oxygen demand and therefore
heart rate and blood pressure.
■ The patient cannot smoke for at least 4 hr prior to test.
■ The patient should not eat or drink anything except water 4 h
prior to test. Coffee, tea, or carbonated or caffeinated
beverages are not allowed.
■ For the diabetic patient, the primary care physician and the
cardiologist performing the study should be consulted
regarding insulin/oral hypoglycemic medication adjustments;
however, usually the insulin dose will be halved and the
patient may have orange juice in the morning.
■ The primary care physician or cardiologist performing the test
should be consulted about withholding or adjusting beta-blockers before the test. Beta-blockers include atenolol
(Tenormin), metoprolol (Lopressor, Toprol), nadolol (Corgard),
and propranolol (Inderal). Check the patient’s medications
including all natural and over-the-counter products and notify
the echocardiographer for orders about withholding cardiac
■ The patient will receive an IV and dobutamine will be
administered during the echocardiogram.
■ Patients may feel tachycardic, short of breath, or have a
headache. The patient should report all physical sensations to
the echocardiographer.
■ After the study, the patient will remain in the testing area until
any side effects subside.
■ If the patient returns to a patient care floor, his or her vital
signs should be monitored.
Vascular Ultrasound Studies (Doppler
Ultrasound, Duplex Scan)
■ Vascular ultrasound studies provide information about the
structure and patency of blood vessels by combining standard
ultrasound, which produces an image of the blood vessel, and
Doppler ultrasound, which produces a graph or audible sound
that reflects the velocity of blood flow though the blood
■ The velocity of the blood can be used to determine if a blood
vessel is occluded and the degree to which it is occluded.
■ These studies are referred to as Doppler Ultrasound or Duplex
■ Continuous-wave (CW) Doppler (bedside Doppler) refers to a
hand-held device used to hear the blood flow in the
extremities when pulses cannot be palpated. It is frequently
performed at the bedside. Acoustic gel is applied over the
presumed arterial site and the transducer is lightly applied to
the area until blood flow is detected.  Notify health care
provider if pulses cannot be detected by Doppler.
■ Color Doppler is the application of color (red or blue) to
standard ultrasound images of blood vessels to show the
speed and direction of blood flow.
■ Power Doppler is a technique that is more sensitive at
detecting low blood flow than color Doppler and is used to
evaluate blood flow through organs.
■ The procedure for Duplex scans is similar to that of any
■ The most common duplex scans involve the carotid arteries,
the arteries of the legs, or the venous system of the legs.
■ Transcranial Doppler and a duplex scan of the abdominal
vessels are also done.
Carotid, Arterial, or Venous Duplex Scan
For all the following Doppler studies, refer to Pretest Preparation,
Procedure, and Posttest Care for Ultrasound on page 139 and
General Pretest Patient Education in Tools section.
Vascular Duplex Scans
Test Ordered Indications/Comments
Carotid Duplex
Arterial Duplex
Scan of Lower
Venous Duplex
Scan of Lower
◆ Plaque or stenosis, occlusion, aneurysm, and
◆ May include assessment of major vertebral
◆ Provide quantitative measurements of the
severity of stenosis.
◆ Assessment of the femoral artery and its
branches down into the calf.
◆ Plaque or stenosis, occlusion, aneurysm, arterial
insufficiency, presence of collateral circulation,
patency of graft site, and embolism.
◆ May include measurement of the ABI (ankle-brachial index). ABI is the ratio of the highest
systolic pressure in the ankle vessel to the
highest brachial systolic pressure. Used to
predict the severity of peripheral arterial
disease. A normal resting ABI is 1 or higher.
◆ May also be done on upper extremities
◆ DVT, thrombophlebitis, and venous
◆ Changes in venous blood flow characteristics
before and after respiration are assessed to
provide information about venous occlusion.
Compression using gentle pressure is also
◆ Limitations of the study include:
• Less accurate for detecting thrombi in the calf.
• May not be able to distinguish between old
and new clots.
• Not helpful in diagnosing postoperative
asymptomatic DVT.
Carotid Duplex Scan
US of carotid artery. Yellow area indicates blockage.
◆ Detect tumor; evaluate symptoms of UTI;
assess bladder for residual urine.
◆ Must have a full bladder for study.
◆ Evaluate abnormality detected by
mammography; drainage of breast cysts
and biopsy of breast masses.
◆ Not approved for breast cancer
◆ Detect masses; differentiate between
cyst and solid tumor; and aid in the
diagnosis of kidney disease including
infection, hydronephrosis, and renal
◆ Evaluate abdominal pain, suspected
gallstones, abdominal mass, enlarged
spleen, abnormal liver function tests, or
jaundice; assess for ascites, abdominal
infection, and tumors.
◆ Patient may need to restrict food and
fluid before test.
◆ Evaluate rotator cuff tear, shoulder pain,
muscle tear, mass in soft tissues,
tendonitis, or acute injury.
Other Ultrasound Studies
Bladder, Breast, Kidney, Liver/Biliary,
Musculoskeletal, Obstetric, Pelvic, Prostate,
Scrotal, and Thyroid  Ultrasound Tests
For all the following ultrasound studies, refer to Pretest
Preparation, Procedure, and Posttest Care for Ultrasound on
page 139 and General Pretest Patient Education in Tools
Common Ultrasound Tests
Test Ordered Indication/Comments
(Abdominal US)
Test Ordered Indication/Comments
Scrotal or
◆ Estimate fetal age; number of fetuses;
evaluate abnormal bleeding, abnormal
fetal heart beat, diabetes, follow-up for
possible fetal abnormality.
◆ Evaluate testicular pain, mass, swelling,
or trauma; infertility assessment.
◆ Pelvic pain or mass; ectopic pregnancy,
abnormal bleeding, screening for ovarian
cancer; infertility work-up.
◆ Uses an intravaginal transducer.
◆ Follow-up to elevated PSA; assess
prostate after abnormal rectal exam.
◆ Uses an transrectal (internal) transducer.
◆ Assess mass or nodule; follow-up to
abnormal thyroid blood tests, history of
neck irradiation, or abnormality seen on
other tests.
Overview of Nuclear Medicine Scans
■ In nuclear medicine scanning, a radioactive isotope (called a
radionuclide, a radiopharmaceutical, or a tracer) is introduced
into the body orally, by inhalation, or intravenously.
■ The isotope travels through the bloodstream and accumulates
(called “uptake”) to varying degrees in different tissues. The
radionuclide then begins to decay, emitting radiation that can
be detected with a gamma camera.
■ The gamma camera contains a detector called a scintillation
crystal. It scans the area of interest detecting the signals
emitted by the radiation.
■ The radiation signals are converted into light, the light is
converted into an electric signal, and the electric signal is
digitized. The computer can then provide an image of body
structure and function that can be viewed on a monitor and
How Nuclear Scans Show Disease
■ A nuclear scan reveals disease because the degree to which
tissues take up radiation reflects the metabolic activity of that
tissue. Hypofunctioning tissue takes up less radionuclide than
normal tissue and hyperfunctioning tissue, like cancers, takes
up more.
■ In normal tissues, the radionuclide is evenly distributed and
shows up as uniformly gray. In abnormal tissues, the
radionuclide shows up as either bright white— a “hot spot”
indicating hyperfunction, or dark—a “cold spot” indicating
■ The nuclear medicine image can be colorized to clearly show
functional activity.
■ Nuclear medicine body structure images are not as detailed
as those obtained with magnetic resonance (MR) or computed
tomography (CT), but the functional information obtained
through nuclear scanning is very helpful in detecting disease.
Safety Issues with Nuclear Scans
■ Nuclear medicine studies involve exposure to considerably lower
doses of radiation than conventional x-rays or CT scans.
■ Patients should be told to drink several glasses of water after nuclear
scans to help excrete the radioactive isotope. All of the isotope will be
excreted within a few days.
■ Tell the patient that the isotope is only weakly radioactive and that their
exposure does not represent a risk to themselves or family members.
■ Inform the patient that the radiation dose for a nuclear scan is much
less than the dose received when undergoing radiation treatment.
■ Pregnant or nursing women should not have nuclear scans.
■ Allergic reaction to the radioisotope is rare.
Whole skeleton bone scan. Diagnosis for this patient was degenerative joint
disease in multiple sites (see arrows indicating increased uptake in the cervical
spine, wrist, ankle, and toes).The arrowhead indicates a total joint prosthesis at
the knee.
Nuclear Medicine Imaging Techniques
■ SPECT (single photon emission computed tomography) acquires
multiple views using a rotating gamma camera. It provides 3-D
computer-reconstructed images of function.
■ PET (positron emission tomography) is the most sensitive
technique for imaging metabolic and biochemical pathways.
◆ Biochemical activity in diseased tissues and cells changes
before structure changes; therefore PET scanning can reveal
disease in its very early stages.
◆ Using different types of radionuclides and two opposing
detectors, PET provides 3-D computer-reconstructed images of
physiology and function. Radio tracers used for clinical PET
imaging include:
◆ O-15–labeled water, used to measure blood flow in the
◆ N-13-labeled ammonia, used to measure blood flow in the
◆ FDG, a radioisotope-labeled glucose molecule, used to
measure metabolic processes throughout the body. For
example, the brain uses glucose for energy. By tagging a
glucose molecule with a radioactive tracer and then scanning
the patient’s brain, PET can identify abnormal areas of the
brain by revealing areas that are underutilizing glucose.
◆ Many other tracers are under development.
■ FDG-PET is gaining wide use in the diagnosis, staging, and
treatment planning of many cancers. The higher rate of glucose
metabolism in cancer cells makes cancer cells appear as hot
spots in PET images. Because extremely minute amounts of FDG
can be detected, FDG-PET scans are capable of detecting cancers
long before anatomic changes are apparent.
■ FDG-PET has applications in cardiology, neuropsychiatry, and
other disease processes as well.
■ Dual-Modality PET/CT imaging combines both PET and CT
scanning in one device, merging the incomparable molecular
imaging of PET with the detailed anatomic images of CT. PET/CT
will dramatically change diagnosing, staging, treatment, and
restaging of cancer patients. In addition to the improved
diagnostic capability, PET/CT has the advantage of decreasing
overall scanning times for cancer patients who typically undergo
multiple scans throughout the course of their disease.
Bone Scan (Whole Body Bone Scan)
Nuclear scan to detect abnormal bone. Can show bone changes
earlier than conventional x-ray.
■ Assess patients with unexplained bone pain.
■ Assess for infection, tumor, bone metastasis, and fracture.
■ Assess for conditions such as Paget’s disease, tuberculosis,
renal osteodystrophy, bone infarction, etc.
The patient receives an IV injection of the radioactive isotope
(tracer). It takes 2–4 hr for the tracer to circulate and be
absorbed by the bones, so the patient must wait until the
correct time to scan. The patient is asked to drink water during
this time to help excrete any unabsorbed isotope.
For scanning, the patient lies on the imaging table and the
gamma camera passes over the body taking images. The entire
body or a specific area can be scanned.
In a 3-phase bone scan, a series of images is taken at different
times—first immediately after the tracer is injected to assess
blood supply, 10 min after the tracer is injected, and again in
2–4 hr to assess osteoblastic activity.
■ See General Pretest Patient Education in Tools Tab.
■ Inform the patient about the time it takes for scanning.
■ There is no specific posttest care.
Brain PET (Positron Emission Tomography
of the Brain, FDG Brain Scan)
PET (positron emission tomography) is a nuclear scan that shows
biochemical function and activity. In brain PET, fluorine-18– labeled
fluorodeoxyglucose (FDG), a radioactive version of glucose, is
administered and disperses in the brain. The brain uses glucose as
its main energy source; however, normal and abnormal cells
absorb FDG differently.
■ Assess brain tumors and masses; assess effectiveness of
chemotherapy; and distinguish benign from malignant tumors.
Assess for tumor recurrence versus scar tissue.
■ Assess brain injury.
■ Localize the site of seizure activity.
■ Diagnose Alzheimer’s disease and other dementias.
■ Evaluate psychiatric disorders such as schizophrenia or autism.
■ Evaluate movement disorders such as Parkinson’s disease.
■ Map the areas of the brain to help guide surgery.
The patient has an IV started and the radioactive tracer (FDG) is
administered. Uptake time for the PET brain scan is about 30 min;
during which time the patient lies quietly in a dimly lit room. Once
scanning begins, the table moves the patient to different positions
in the scanner so that distribution of the tracer can be accurately
determined. Scanning time is approximately 20 min.
■ See General Pretest Patient Education in Tools Tab.
■ The patient should be NPO for 4 hr before testing.
■ Medications can be taken with a small amount of water.
■ Diabetic patients should have a blood glucose level between 100
and 200 mg/dL as elevated glucose levels can interfere with the
■ There is no specific posttest care.
Brain SPECT Scan (Brain Perfusion Study)
Reveals cerebral blood flow and provides a 3-D image of the brain.
Does not show the anatomy of the blood vessels like angiography
but shows the pattern of perfusion throughout the brain.
Damaged brain tissue shuts down its own blood supply; therefore,
areas of the brain with vascular defects (decreased perfusion)
indicate brain damage. Certain patterns of decreased perfusion are
considered classic findings associated with specific diseases; for
example, Alzheimer’s disease, in which brain SPECT typically finds
bilateral hypoperfusion of the temporal and parietal lobes with or
without involvement of frontal lobes. Informed consent required.
■ Diagnose Alzheimer’s disease and other forms of dementia.
■ Locate seizure foci.
■ Evaluate cerebral ischemia and stroke patients.
■ Evaluate brain injury.
■ Evaluate patients with psychiatric and mood disorders.
■ Detect recurrent brain tumor.
■ Diagnose brain death.
The patient lies on the scanning table and the gamma camera is
positioned around the patient’s head. The technologist then
administers the radioactive tracer intravenously. The camera
immediately begins imaging the brain as the radioisotope (the
tracer) travels into the cerebral circulation. After a waiting period
of 30 min, the patient is repositioned under the camera and
pictures are taken again.
To locate seizure foci: Requires two SPECT scans, one to show
blood flow during a seizure and one to show blood flow without
seizure activity. These will be done on two different days.
To evaluate cerebrovascular disease: Requires two SPECT scans,
one to show the patient’s baseline cerebral blood flow and one to
show blood flow after administration of acetazolamide (Diamox).
Acteazolamide dilates blood vessels and markedly increases
cerebral blood flow; however regions supplied by significantly
stenosed blood vessels will not show an increase in perfusion.
■ See General Pretest Patient Education in Tools Tab.
■ Tell the patient nuclear scanning is not painful and that the
test will take about 1 hr.
■ No special posttest care is required.
Gallium Scan
Total body nuclear scan used to detect inflammation, which is an
indicator of infection or tumor. Radioactive gallium accumulates
in areas of inflammation, infection, and benign or malignant
tumors. Informed consent required.
■ Assess patients with fever of unknown origin and scan for
occult abscess or infection.
■ Evaluate bronchogenic cancer, lymphoma, liver tumors, and
malignant melanoma.
The patient receives an IV injection of the radioactive isotope.
Scanning may begin as early as 4–6 hr later; however, since it
takes longer for gallium to be taken up by the tissues, scanning
is usually performed at 24-, 48-, and 72-hr intervals. For
scanning, the patient lies on the imaging table while the
gamma camera moves over and around the body.
Scanning takes 1 hr to 90 min.
■ See General Pretest Patient Education in Tools Tab.
■ Gallium accumulates in the large intestine before excretion;
therefore a laxative the evening before and an enema 1 hr
before scanning may be required to avoid interference with
the results.
■ There is no specific posttest care.
Gastric Emptying Scan
Nuclear scan to assess symptoms of delayed gastric emptying.
■ Assess for diabetic gastroparesis, pyloric stenosis, or ileus.
The patient ingests an egg sandwich and juice that have been
“labeled” with a radionuclide. The emptying of the food from the
stomach is then followed over 1–2 hr.
■ See General Pretest Patient Education in Tools Tab.
■ The patient should be NPO for 4 hr before the test.
■ Tell the patient nuclear scanning is not painful and that the test
will take about 1 hr.
■ No special posttest care is required.
Gastrointestinal Bleeding Scan (Abdominal or
GI Scintigram, Tagged Red Blood Cell Scan)
Nuclear scan that uses the patient’s red blood cells and a
radioisotope to identify the source of GI bleeding. Because the
blood is tagged with a radioactive isotope, the gamma camera can
detect the blood when it pools in the GI tract.
■ Localize the site of active gastrointestinal bleeding.
■ Aids in endoscopic or surgical repair of bleeding since visually
locating bleeding source can be quite difficult for the surgeon.
■ May be done prior to angiography.
The patient has an IV started in the nuclear medicine department.
The patient’s blood is “tagged” with a radioactive isotope, usually
by mixing the isotope (technetium-99m) with a sample of the
patient’s RBCs and then reinjecting it into the patient. The
radionuclide remains in the circulation and will extravasate into
the lumen of the bowel at the site of the GI bleeding.
Scanning is performed immediately, after a delay, or several
times at intervals over the day.
■ See General Pretest Patient Education in Tools Tab.
■ Tell the patient nuclear scanning is not painful and that the
test will take about 1 hr.
■ Patients with a suspected GI bleed may be quite sick and
unstable. Assess vital signs, obtain latest hemoglobin and
hematocrit results, and observe for signs and symptoms of
■ Arrange for someone to accompany the patient to nuclear
scanning if the patient is unstable.
■ No special posttest care required.
Liver/Spleen Scan
Nuclear scan of the liver and spleen.
■ Detect abscess, cyst, benign tumor, cirrhosis, or hepatitis.
■ Assess liver and spleen following abdominal trauma.
■ Detect primary or metastatic tumor.
The patient has an IV started in the nuclear medicine
department. The radioactive isotope is administered IV and is
taken up by the liver and spleen within a few minutes. After 15
min, the images will be taken. SPECT scanning provides the
best images.
■ See General Pretest Patient Education in Tools Tab.
■ Tell the patient nuclear scanning is not painful and that the
test will take about 1 hr.
■ No special posttest care is required.
Lung Scan (V/Q Scan, Ventilation
and Perfusion Lung Scans)
Nuclear scans that assess pulmonary perfusion and ventilation.
Each is a separate test but typically both are performed at the
same time to evaluate the possibility of pulmonary embolism (PE).
The results of the perfusion scan are compared to the results of
the ventilation scan to estimate the probability of PE. Informed
consent required.
■ Evaluate patients with signs and symptoms of PE.
■ Assess pulmonary perfusion.
■ Assess lung function; evaluate asthma, pneumonia, obstructive
lung disease, cystic fibrosis, and other lung diseases.
Ventilation scan: The patient inhales the radioactive tracer through
a face mask. The patient will have to hold his or her breath and
assume different positions while the gamma camera images the
lungs. In certain pathologic lung conditions, pneumonia and
emphysema, for example, the radioactive gas will not be evenly
distributed as diseased tissue or exudates obstruct the airways
and impede ventilation. In PE, the airways are not obstructed and
the ventilation scan is normal.
Perfusion scan: The patient lies on the imaging table and receives
an IV injection of a radioactive tracer. The gamma camera scans
the lungs to image the distribution of the tracer throughout the
pulmonary blood supply. If the perfusion scan is abnormal, i.e.,
there are areas of the lungs not being perfused normally, it
indicates obstruction of blood flow. If the areas of obstructed
blood flow correlate with the areas of poor ventilation, it suggests
lung disorders such as pneumonia or emphysema. If the
ventilation scan is normal but the perfusion scan shows areas of
obstructed blood flow, it suggests pulmonary embolism.
■ See General Pretest Patient Education in Tools Tab.
■ Explain the procedure to the patient; there are no special pretest
■ There is no specific posttest care.
■ Patients who require a lung scan are potentially unstable.
Monitor the patient closely before and after the test. Implement
interventions to improve respiratory status without delay.
Ventilation scan showing no filling defects
Perfusion scan of same patient showing defect in the RUL consistent with
pulmonary embolism.
Multigated Blood Pool Imaging (MUGA Scan,
Cardiac Blood Pool Scan, Ventriculogram,
Radionuclide Angiogram [RNA]).
Nuclear scan that images the blood within the cardiac chambers
and provides information about contractile (pumping) function
of the myocardium. The study can be performed at rest and/or
with exercise for comparison.
■ Assess effects of chemotherapy on cardiac muscle.
■ Assess for weakened cardiac muscle, areas of previous
myocardial infarction, and ventricular aneurysm.
■ Determine ejection fraction (EF).
The patient lies on the table, has an IV started, and has ECG
electrodes placed on the chest. Blood will be withdrawn so that
it can be labeled with a radioisotope. After the blood is
reinjected, the gamma camera will move over the patient’s
chest and begin imaging the heart.
The gamma camera is synchronized with the ECG to trigger
imaging of the heart and blood flow at specific times during the
cardiac cycle. Images of the heart in motion can then be viewed
to determine whether the ventricle is contracting properly. The
computer will analyze the amount of blood ejected from the
ventricles to provide the ejection fraction (EF).
■ See General Pretest Patient Education in Tools Tab.
■ The patient should be NPO for 4 hr before the test.
■ Tell the patient nuclear scanning is not painful and that the
test will take 1–2 hr.
■ No special posttest care is required.
Myocardial Perfusion Scan (Stress Thallium
Scan, Sestamibi Scan, Treadmill-Mibi)
Nuclear SPECT scan that provides information about coronary
blood flow, cardiac function, and ventricle size. The radionuclide
used may be thallium, tetrofosmin, or cardiolite. Myocardial
perfusion scans include:
◆ Resting scan: Performed at rest to detect areas of ischemic
◆ Exercise scan: Performed with the patient exercising to assess
for areas of ischemia.
◆ Persantine, adenosine, or dobutamine scan: Administered to
patients who are unable to exercise. These drugs are
vasodilators and will increase coronary artery blood flow
without exercising.
Informed consent is required. Potential complications include
dysrhythmias and myocardial ischemia. Contraindicated in acute
myocardial infarction, unstable angina, uncontrolled cardiac
arrhythmia, severe aortic stenosis, symptomatic heart failure,
acute pulmonary embolus, myocarditis or pericarditis, or aortic
■ Evaluate chest pain, assess for coronary artery disease, evaluate
collateral circulation, and assess graft patency.
■ Evaluate myocardial infarction.
The patient has an IV started, electrodes placed on the chest, and a
blood pressure monitor placed around the left arm.
For an exercise test: The patient begins exercising on a treadmill or
exercise bike. The rate and incline of the treadmill or the resistance
to pedaling are increased incrementally. The patient’s heart rate,
blood pressure, and perceived degree of exercise are monitored
throughout. At the point of maximum exertion, the radionuclide is
injected and the patient continues to exercise for another minute
or two. The intensity of the exercise is decreased until the patient
stops exercising. The patient is then escorted to the scanning room
and placed supine on the table. The gamma camera rotates around
the patient, taking multiple images. If an area of the heart is
ischemic, it will take up less of the radionuclide and will appear
as a dark area, which is called a defect. After a waiting period,
the patient is scanned again.
For a resting test: the patient does not exercise but lies on the
scanning table. The radionuclide will be administered and,
depending on which radionuclide is used, the gamma camera
will begin scanning within 10–60 min.
For a persantine, adenosine, or dobutamine scan: A resting
perfusion scan is usually performed first. Next, instead of
exercising, the patient is given persantine, adenosine, or
dobutamine IV over several minutes. The patient may
experience flushing, chest pressure, shortness of breath,
dizziness, nausea, or headache during administration of the
vasodilators.  Adenosine and dipyridamole (Persantine) can
cause hyperventilation and bronchospasm and should not be
given to patients with asthma or bronchospasm. Dobutamine is
contraindicated in patients with uncontrolled hypertension,
unstable carotid artery disease, significant ventricular ectopy,
and glaucoma.
After the infusion is complete, the radionuclide is administered
and the patient is scanned.
■ See General Pretest Patient Education in Tools Tab.
■ Tell the patient not to eat or drink for 4 hr prior to the test.
■ Beta blockers, ACE inhibitors, and calcium channel blockers
may diminish test efficacy.  Check with physician about
withholding these medications.
■ The patient should not drink caffeinated beverages for 24 hr
before the test or take medications that contain theophylline
for 48 hr before the test. Caffeine and theophylline interfere
with and weaken the effects of adenosine and dipyridamole.
■ Vital signs and ECG should be obtained before the test.
■ No special posttest care is required. However, patients with
known cardiac disease should be assessed for up to 24 hr
after testing for signs and symptoms of cardiac ischemia.
Renogram and Renal Perfusion Scan
(Furosemide Renal Scan, Captopril Renal Scan,
Renal Scintigraphy)
Renal nuclear scans assess perfusion, structure, and function of the
kidneys. They are the preferred diagnostic studies in children and
patients with preexisting renal disease because exposure to
iodinated contrast is avoided.
A Captopril renal scan is used to diagnose renal hypertension. In
patients with renal artery stenosis, glomerular filtration is
maintained by angiotensin. By administering captopril, an ACE
inhibitor, this compensatory mechanism is temporarily removed
and a transient decrease in the GFR will be seen.
A furosemide renal scan is used to increase output and observe for
outflow obstruction.
■ Assess patients with acute or chronic renal failure.
■ Aid in the diagnosis of renal artery stenosis, renal vein
thrombosis, and renal artery embolism or infarction.
■ Evaluate kidneys after trauma.
■ Assess for infection such as renal abscess or nephritis.
■ Evaluate chronic UTI.
■ Assess transplanted kidney for acute or chronic rejection.
The patient has an IV started and the radioisotope is administered.
The patient either sits or lies prone on the scanning table.
Scanning occurs at various times, depending on which test is
being performed. If the patient is having a furosemide test, the
medication is administered IV. Captopril is given by mouth and
scanning is done 1 hr later.
■ See General Pretest Patient Education in Tools Tab.
■ To enhance the accuracy of the results, the patient should be
well hydrated before the study.
■ The patient should void before the study.
■ No special posttest care is required.
Other Nuclear Scans
The nuclear scans cited below are conducted similarly to other
nuclear scans: The patient receives a radioactive isotope and is
scanned by a gamma camera while lying on the scanning
table. Generally, there is no pretest preparation; call the
nuclear medicine department if in doubt. There is no specific
posttest care, although some facilities suggest drinking plenty
of fluids to help flush out the isotope.
Cardiac Scans
Test Name Indications
Tomography (PET)
Scan/ Myocardial
First-pass Study
(Cardiac Flow,
Shunt Imaging)
Infarct Avid PYP
Scan (Myocardial
Infarction Scan)
◆ PET scans give information about
coronary artery blood flow. Also used
to assess myocardial viability prior to
revascularization procedures.
◆ Viable areas of the heart will have
greater uptake of the radioisotope and
appear as hot spots. Cold spots (darker
areas with less uptake) indicate areas
that are not viable.
◆ Assess heart chamber disorders,
especially septal defects.
◆ Radiopharmaceutical is injected and
multiple images are taken as the tracer
makes its “first pass” through the great
vessels and chambers.
◆ Used to evaluate chest pain, equivocal
EKG changes, or increased CPK; assess
for extension of MI, and rule out or
diagnose acute myocardial infarction.
Tc-99m PyP, the radioisotope, is taken
up by necrotic myocardial cells.
◆ Timing of scan is very important;
should be done within 48–72 hr after
onset of symptoms.
(Continued on following page)
Endocrine Scans
Test Name Indications
Thyroid Scan
GI and Hepatobiliary Scans
Test Name Indications
Hepatobiliary Scan
(HIDA Scan,
Hepatic Arterial
Perfusion Scan
Reflux Scan
Meckels Scan
(Gastric Mucosal
◆ Detect and localize hyperfunctioning
parathyroid adenomas.
◆ Determine thyroid size, function, and
position and evaluate functional status
of thyroid nodules.
◆ Evaluate of thyroid and neck masses.
◆ Evaluate of patients with history of
head and neck irradiation.
◆ Quantitative thyroid uptake (I-131
◆ Assess for acute or chronic
cholecystitis, sphincter of Oddi spasm,
biliary dyskinesia, and bile leak or
◆ HIDA is the radioactive tracer that is
injected IV, travels to the liver, and is
excreted through the biliary system.
◆ Assess for suspected liver metastasis.
◆ Frequently done simultaneously with
CT portography.
◆ Detect and quantitate reflux.
◆ Evaluate suspected aspiration
◆ Diagnose Meckle’s diverticulum in the
small bowel.
◆ Very sensitive and specific test.
(Continued on following page)
Test Name Indications
Peritoneal Shunt
Schilling’s Test
Tagged RBC
Liver/Spleen Scan
Urea Breath Test
(UBT, H. pylori
Breath Test)
Octreotide Scan
Oncoscint Scan
White Blood Cell
◆ Assess patency of peritoneal shunts.
◆ Requires injection of radionuclide into
ascites fluid.
◆ Evaluate cause of vitamin B12
deficiency. Requires IM administration
of vitamin B12 and ingestion of
radioactive tracer bound to vitamin B12
followed by 24-hr urine collection.
◆ The radioactive B12 should be excreted
in the urine.
◆ Assess for hepatic hemangioma.
◆ Uses tagged red blood cells and SPECT
◆ Assess for H. pylori bacteria in the
◆ The patient provides a breath sample
(breathes into a tube) after ingesting a
capsule with trace amounts of a
radioactive substance.
◆ Image, detect, follow-up, and
monitoring of neuroendocrine tumors.
◆ Detect recurrent colorectal and ovarian
◆ Evaluate lymph channels in patients
with malignant melanoma or breast
◆ Evaluate patients with inflammatory
bowel disease.
◆ Detect abscess or acute (4–6 weeks)
◆ Evaluate fever of unknown origin and
assess for acute osteomyelitis or
prosthesis or graft infection.
■ Visualization of a joint space, usually the knee or shoulder,
with an arthroscope. The arthroscope is connected to a video
camera and the joint is viewed on a monitor. If a procedure is
planned, instruments are inserted through the arthroscope or
through separate incisions. Removal of cartilage, repair of
torn ligaments, and removal of inflamed or damaged lining
(synovectomy) are a few of the procedures performed during
■ Arthroscopy is performed using general, spinal, or regional
anesthesia. Preoperative and postoperative care are required.
Potential complications include infection and the risks of
■ Biopsy is the removal of tissue for microscopic examination.
■ Types of biopsies include:
◆ Needle biopsy: Includes fine needle and core needle
biopsies. Fine needle aspiration (FNA) uses a thin needle
and a syringe to withdraw a small amount of fluid and
small pieces of tissue from the tumor. In a core biopsy, the
needle is larger in diameter and removes a small cylinder of
tissue. It is done using local anesthesia. If the tumor cannot
be palpated, FNA or core biopsy can be done under
fluoroscopic, ultrasonic, or CT guidance.
◆ Excisional or incisional biopsy: Excisional biopsy involves
removal of the entire tumor. Incisional biopsy involves
removing a small piece of the tumor. Depending on the
tumor location, excisional or incisional biopsy is done
under local, regional, or general anesthesia.
◆ Endoscopic biopsy: Involves removal of tissue during an
endoscopic procedure of the gastrointestinal, genitourinary,
or the respiratory tract.
◆ Laparoscopic and thoracoscopic biopsy: Removal of tissue
during laparoscopy, which is performed to view and obtain
samples from the abdomen, or thorascopy, which is
performed to view and remove samples from the chest.
Both require a small incision.
■ Direct visualization of the larynx, trachea, and bronchi with a
bronchoscope. Used diagnostically for biopsy, aspiration of
sputum for C&S and cytology, and direct examination of
tissues and structures. Used therapeutically for removal of
obstructing tissue, secretions, or foreign object.
■ Bronchospy is performed using sedation and local anesthesia.
Requires pre- and postprocedure care. Potential complications
include hypoxemia, aspiration, pneumothorax, and complica-tions associated with anesthesia. Assess gag reflex after
bronchoscopy and withhold all foods or fluids until patient is
awake and alert and gag reflex has returned.
■ Catheterization of the right or left heart to visualize the
coronary arteries, the great vessels, and the chambers of the
■ The catheter is inserted into the groin or arm and guided
under fluoroscopy into the heart. The procedure involves
taking blood pressure measurements within the heart’s major
arteries, sampling blood for oxygen content, coronary
angiography, which requires use of an iodinated contrast, and
a left ventriculogram, which also requires contrast and
provides information about coronary blood flow.
■ Pre- and postprocedure care are required. Complications
include stroke, reaction to contrast, perforation of blood
vessels, heart attack, air embolism, dysrhythmias,
thrombosis, and death.
■ Direct visualization of the colon from the anus to the cecum
using a colonoscope. Used to identify causes of lower GI
bleeding, screen for colon cancer, assess patients with
ulcerative colitis, remove polyps, and biopsy suspicious
■ Patients receive conscious sedation for the procedure.
Requires a thorough bowel prep. Requires pre- and
postprocedure care. Potential complications include
perforated colon and the risks of conscious sedation.
■ Direct visualization of the cervix and vagina using a
colposcope, which includes a magnifying lens to better
examine suspicious tissue. Is performed after an abnormal
Pap smear and to evaluate daughters of women who received
diethylstilbestrol while pregnant.
■ Does not require specific pre- or postprocedure care. If a
biopsy is performed (conization), the patient may experience
bleeding for several hours. The patient should refrain from
intercourse for 1 wk.
■ Assessment of detrusor muscle (the bladder muscle) function
to evaluate cause of incontinence or other bladder
■ The patient is catheterized and sterile saline is instilled into
the bladder. The patient is asked to report sensations of
fullness and urge to void.
■ The test evaluates sensation, bladder function, and pressures
during filling. It also measures total bladder capacity, detrusor
compliance, and the ability to empty the bladder normally.
Uninhibited bladder contractions, abnormal bladder wall
compliance, and stress incontinence are measured.
■ Also includes urine flowmetry, in which the patient voids into
a special commode. Urine flow rate is then measured, which,
when low, suggests diminished bladder contractility or outlet
obstruction. High flow rates suggest poor urethral function,
high voiding pressures, or a combination of both.
■ Study that measures the brain’s electric activity. Electrodes
placed on the scalp transmit the signals of electric activity to
the EEG machine, which records the amplitudes on graph
■ Used to evaluate seizure disorders, identify brain abcesses
and tumors, evaluate head injuries, monitor cerebral blood
flow during surgeries that affect cerebral blood flow (carotid
endarterectomy), and establish brain death.
■ Study that measures the electric activity of skeletal muscles at
rest, during voluntary contraction, and with electric stimulation.
■ Electric “mapping” of defects in the heart’s conduction system.
A catheter with multiple electrodes in its tip is threaded under
fluoroscopy into the right heart via a peripheral vein. The loca-tion of sites responsible for dysrhythmias can be identified by
pacing the heart and then inducing dyrhythmias. Radiofrequncy
waves can be used to obliterate the sites.
■ Requires pre- and postprocedure care. Potential complications
include stroke, hemorrhage, ventricular tachycardia or fibrilla-tion, and myocardial perforation.
■ ERCP combines x-rays and endoscopy to visualize the biliary
pancreatic ducts. Used primarily to diagnose and treat
gallstones, strictures, tumors, or cysts.
■ A flexible fiberoptic endoscope is inserted into the esophagus,
through the stomach, and into the descending duodenum.
■ A catheter is inserted through the endoscope into the common
bile duct.
■ After the catheter is in place, contrast is injected into the biliary
ducts and pancreas.
■ Release of strictures, removal of obstruction, and tissue
samples (biopsy) may be taken during the procedure.
■ Pre- and postprocedure care are required. Potential complica-tions include pancreatitis, infection, bleeding, and duodenal
■ Manometric tests that measure the pressure of the lower
esophageal sphincter and esophageal motility. Performed by
passing a pressure-sensitive catheter into the esophagus and
slowly withdrawing it.
■ Esophageal function studies include pH monitoring, esophageal
acidity assessment, and an acid-perfusion test, which helps to
distinguish esophageal pain from cardiac pain.
■ Endoscopic examination of the esophagus, stomach, and
duodenum. EGD is both diagnostic and therapeutic.
Interventions possible during EGD include coagulation of
bleeding vessels, biopsy, dilatation of stictures, stent
placement (in the biliary system), and gastrostomy.
■ Pre- and postprocedure care are required. Potential
complications include perforation, aspiration, or
complications associated with conscious sedation.
■ Studies that measure electric signals along nerve pathways.
Used in the diagnosis of demyelinating diseases, stroke,
spinal cord injury, hearing loss, Parkinson’s disease,
peripheral nerve damage, and other conditions in which nerve
damage is a feature.
■ Neural activity is evoked by visual stimulation, auditory stim-ulation, or somatosensory stimulation (mild electric shock).
■ Cardiac monitoring of the fetus for indicators of stress. Types
of monitoring include:
◆ External Fetal Monitoring: Electrodes that sense fetal heart
rate and contractions are placed on the abdomen. Assess
how well the fetus is tolerating contractions.
◆ Nonstress Test  (NST): Measures the FHR accelerations with
normal (fetal) movement. FHR should accelerate by
15 bpm during a 20-min interval. If the baby does not move
during the initial testing time, massaging the abdomen or
using a loud noise to stimulate fetal movement may be
◆ Contraction Stress Test (CST): Contractions are induced
either by nipple stimulation (nipple stimulation test) or
oxytocin (oxytocin challenge test [OCT]). The FHR should
not show late deceleration during contractions, which may
indicate hypoxia.
◆ Internal Fetal Monitoring: Involves placing an electrode
directly on the fetal scalp through the cervix. Performed if
external monitoring is not working reliably. The electrode is
placed transvaginally. The wire is strapped to the mother’s
thigh and attached to a monitor.
■ Ambulatory ECG monitoring in which the patient has
continuous ECG monitoring for 24 hr. The patient has ECG
leads placed on his or her chest. The leads are attached to the
Holter monitor, which is a small baterry-operated recorder.
The patient keeps a diary for 24 hr noting symptoms and
engaging the event marker on the monitor when he or she
experiences cardiac symptoms. The recordings are later
reviewed by a cardiologist.
■ Holter monitoring is used to identify transient dysrhythmias.
■ Noninvasive method of monitoring the percentage of
hemoglobin (Hb) that is saturated with oxygen. The pulse
oximeter is a probe linked to a computer. The probe is placed
on the patient’s finger or ear lobe. The oximetry unit displays
the percentage of Hb saturated with oxygen.
■ Values under 90% indicate severe hypoxemia.
■ Assessment of the functional status of the lungs using a
spirometer connected to a recorder. Used in the work-up of
patients with respiratory symptoms, to quantitate degree of
respiratory impairment, to assess pulmonary status before
surgery, and in the ongoing assessment of patients with
known pulmonary disease.
■ Basic functional status is determined by measuring:
◆ The amount of air that can be moved in and out of the
◆ How quickly the air is moved in and out.
■ Spirometry with flow volume loops measures expiratory
volumes and flow rates. In a sitting position with nose clips
on, the patient breathes into a mouthpiece making a maximal
inspiratory and expiratory effort. Flow volume loop is a
method that graphically illustrates the patient’s inspiration
and expiration. While the patient uses the spirometer, the flow
rate is digitized and plotted against the volumes. The result is
a graph showing a continuous loop from inspiration to
expiration. The shape of the flow volume loop is important in
interpreting results.
■ PFTs are taken again after administration of a bronchodilator
to determine if there is improvement in the expired volumes
and flow rates. They are also repeated after inhalation of
methacholine to induce bronchial hyperreactivity. Asthmatic
patients will demonstrate hyperreactivity at much lower
■ Spirometry results are reported in absolute values and as a
predicted percentage of normal. However, normal values vary
depending on gender, race, age, and height. Also, reference
ranges vary with the laboratory. Reference formulas must be
applicable to the patient population being tested.
■ Many specialized PFTs acquire other types of information;
however, basic spirometric tests still provide considerable
detail and include:
Basic Pulmonary Function Tests
Test Description
FVC—Forced Vital
Expiratory Volume
in 1 Sec
FEV1/FVC—the ratio
of FEV1 to FVC
(also called %FEV1)
Residual Capacity
RV– Residual Volume
TLC—Total Lung
Expiratory Flow Rate
After taking the deepest breath
possible, the FVC is the volume of air
that can be forcibly and maximally
exhaled until no more can be
The volume of air that can be forcibly
exhaled from the lungs in the first
second of a forced expiration.
Indicates the percentage of the total
FVC exhaled during the first second
of forced exhalation.
The amount of air left in the lungs after
normal expiration.
The amount of air left in the lungs after
maximal expiration.
The total amount of air in the lungs at
maximal inspiration
The maximum exhaled flow rate.
■ Performed to evaluate vasovagal or neurocardiogenic
syncope (fainting), which occurs when heart rate slows and
blood pressure decreases secondary to an abnormal reflex of
the nervous system that causes blood vessels to dilate.
■ The patient has an IV started, has continuous ECG and blood
pressure monitoring, and is secured to the table. The table is
tilted to 60–80 degrees for 45 min. If the patient does not faint,
isoproterenol is administered; the patient is then tilted again
for another 45 min. If the patient does not faint, the test is
considered negative. If the patient faints, the tilt table will be
laid flat and the patient will be monitored. Usually recovery is
■ Blood test for pregnant women that checks the levels of hCG
(human chorionic gonadotropin) and estriol, which are
produced by the placenta, and the level of alpha-fetoprotein
(AFP), which is produced by the fetus.
■ The purpose is to identify babies at increased risk for
chromosomal defects such as Down’s syndrome or birth
defects such as neural tube defects.
General Pretest Preparation
All patients undergoing diagnostic testing have similar needs for
information, explanation, and instruction. Instructions should
be provided orally and in writing and in language the patient
can understand (no medical jargon). At the time the test is
ordered, tell the patient:
■ The name of the test, why it’s done, and how it will help with
the patient’s health problem.
■ How the test is done and what the patient will feel during the
■ How to prepare for the test.
■ Risks associated with the test.
■ Factors that will affect the test, such as not following pretest
preparations, moving during the test, interfering medications,
timing of the test, etc.
■ When test results will be available and who will inform the
patient of the results.
■ How to schedule the appointment for the testing and where to
go for the testing.
In addition to providing factual information, always bear in mind
that patients about to undergo diagnostic testing may be
anxious about the test and anxious about the potential results.
Ask and discuss with the patient:
■ What fears or concerns he or she has regarding the test
◆ Fear of pain.
◆ Fear of test results that indicate illness.
◆ Implications of the results;i.e., the next step—possible
treatment plans, need for further testing, medications, etc.
■ Do not minimize the patient’s concerns. Testing and the
possibility of illness are extremely stressful.
At the time of the test, the technician or radiology staff person
will perform a focused assessment, which varies according to
the test. Patients undergoing invasive testing or testing with
iodinated contrast need to have a focused assessment before
the test including assessment of vital signs, pertinent blood
tests, medical history, and history of allergic or other reaction to
Venipuncture Procedure
■ Check the patient’s wrist band against the order sheet or lab
requisition; make sure the patient’s name and hospital
number are legible.
■ Check if the patient is on anticoagulants or has a history
of bleeding disorders. Special care must be taken to achieve
■ Gloves
■ Labels
■ Tourniquet
■ 2  2 gauze pad
■ Alcohol sponge
■ Adhesive strip
■ Sharps container
■ 21- or 22-gauge safety-engineered needle, safety needle
■ Appropriate color evacuated collection tubes. (See Tube Top
Colors, pp. 183-184.)
■ Evacuated tube system: Evacuated tubes have color-coded
tops and fill by vacuum. The tube is used with a collection
tube holder and a safety needle to collect blood directly into
the tube. The collection tube holder helps in handling the
needle and collection tube and allows for changing tubes to
obtain multiple samples with one “stick.” When the collection
tube is disengaged from the needle, a small rubber sleeve
covers the needle and prevents loss of blood while the tube is
■ Syringe method: Uses a 10-mL syringe and a needle to
puncture the vein and aspirate blood. The needle is then
inserted into the colored tube top for transportation to the lab.
■ Butterfly method: Uses a small buttlerfly needle and a syringe
to obtain the venous sample.
■ Place the patient in a supine or semi-Fowler’s position with
ventral surfaces of both arms up.
■ Examine both arms for suitability.  Never draw blood from
the arm if it is on the side of a mastectomy, is edematous, has
an IV below the venipuncture site, has a vascular access or
fistula, or has a hematoma.
■ Tie a tourniquet approximately 4 inches above the intended
venipuncture site. Be sure that it is tight but not uncom-fortable.
■ Ask the patient to make a fist.
■ Assess the antecubital area of the arm. The basilic, cephalic,
and median cubital veins are all usually near the skin surface.
■ Palpate the vein. It should rebound (bounce).
■ If the antecubital veins of both arms are not suitable, assess
the forearms first and then the hands and wrist.
If a suitable vein cannot be found, DO NOT ATTEMPT  BLOOD
DRAW. Remove the tourniquet and inform the nurse in charge or
call the physician.
■ Observe Standard Precautions.
■ Don gloves.
■ Open an alcohol pad and rub the site in concentric circles,
working outward from the center. To avoid patient discomfort,
allow the area to air dry for 30–60 sec (or wipe with a sterile,
dry gauze pad).
■ Povidone-iodine preps may be used. Check if patient is allergic.
■ With your nondominant hand, stabilize the vein by holding
the vein between the index finger and thumb.
■ With your dominant hand grasp the collection tube holder and
turn so that the bevel is UP. Holding the needle at a 15-degree
angle, enter the skin directly above the vein and in the same
direction as the blood flow. Advance needle into vein. Entry
should be smooth and quick.
■ See Other Venipuncture Methods on page 181 for procedures
for obtaining blood with a syringe using a butterfly or a
Venipuncture technique.The thumb of the left hand stabilizes the vein.
■ Ease the collection tube further into the safety needle holder.
■ Remove the tube when it is filled.
■ If the tube contains an additive, gently invert the tube 8–10
times to mix the additive with the blood.
■ Engage subsequent collection tubes as needed.
■ Obtain specimens in the following order:
◆ sterile blood culture tubes
◆ nonadditive clotting tubes (red)
◆ coagulation tubes and tubes containing citrate (blue)
◆ serum-separator tubes (speckled)
◆ tubes containing heparin (green)
◆ tubes containing EDTA (lavender, royal blue)
◆ tubes containing acid citrate dextrose (yellow)
◆ tubes containing sodium fluoride and potassium oxalate
■ Release tourniquet as last tube is filling and disengage the
collection tube from the safety needle.
■ Apply a 2  2 gauze pad over the site and withdraw needle.
■ Apply direct pressure with 2  2  dressing.
■ Raise the arm above the heart level for approximately 3–5 min
to control bleeding, if necessary. Hold gauze in place until
bleeding has completely stopped.
■ Fold a single 2  2 inch gauze pad into quarters and tape it
tightly to the site.
■ DO NOT RECAP, cut, or bend needles. If recapping is done,
use approved “One-Handed Method” or recapping block.
■ Do not separate needle from the blood tube holder. Dispose
of the entire unit in the proper puncture-resistant SHARPS
■ Send to the lab with a properly filled out requisition.
Other Venipuncture  Methods
Venipuncture Using a Syringe
■ Use a syringe when the patient’s veins are small or fragile
because suction from an evacuated tube can cause the vein to
collapse. Using a syringe allows control of the amount of suction.
■ Steps for entry into the the vein are the same as with the
evacuated tube system.
■ Once in the vein, pull back on plunger to obtain desired amount
of blood. Release tourniquet and withdraw needle while applying
a folded gauze 2  2 and pressure to venipuncture site.
■ Transfer blood to appropriate tubes by first replacing needle with
large-bore (18 gauge) needle (prevents hemolysis).
■ Insert needle into the stopper and allow tube to fill by vacuum.
■ Follow the correct order of tube top color.
Venipuncture Using an IV Infusion Set (Butterfly)
■ Used for venipuncture from a very small or fragile vein.
■ For small children use a 23-gauge butterfly IV infusion set
attached to a 1- or 3-mL syringe (prevents excessive suction).
■ Steps for entry into the the vein are the same as with the
evacuated tube system.
■ Grasp the wings between thumb and index finger, hold skin and
vein taut with other hand, and penetrate the skin with the needle.
■ As soon blood is visible in the tube, pull back on the plunger or
engage the vacuum tube. Release the tourniquet, remove the
needle, and complete the procedure.
Skin Puncture
■ Blood for laboratory analysis is sometimes obtained by skin
puncture rather than venipuncture.
■ Sites for skin puncture include the finger, heel (in infants), or ear
lobe. To perform skin puncture:
◆ Select the site.
◆ Apply a warm compress to the site to increase blood flow.
◆ Clean the area with 70% alcohol.
◆ Thoroughly dry the site with a gauze sponge.
◆ Firmly prick the site with a lancet.
◆ To avoid diluting the blood sample with tissue fluid, wipe
away this first drop of blood and do not squeeze or milk the
surrounding tissue.
◆ Collect the blood in a capillary tube, on a slide, onto a test
strip, or into a small container.
◆ If using a capillary tube, hold it horizontally and touch the
end of the tube to the drop of blood without touching the
skin.  The tube will fill by capillary action.
■ Hemolysis is the destruction of the encasing membrane of the
red blood cell and the subsequent release of hemoglobin into
the plasma.
■ Hemolyzed blood specimens can give false values and
therefore are not acceptable for testing.
■ Hemolyzed specimens are often the result of incorrect
venipuncture technique or mishandling of the specimen.
■ Tips to avoid rejected specimens include:
◆ Use a 20- to 22-gauge needle.
◆ If air leaks from around the needle or loss of vacuum
occurs, replace the tube and collect a new specimen.
◆ Do not remove the needle from the vein with the evacuated
tube still engaged in the safety needle. This will cause air to
enter the tube, which can damage red blood cells.
◆ When using a syringe to withdraw blood, pull back on the
plunger gently and evenly to avoid damaging cells.
◆ Allow venipuncture site to dry after cleaning. Alcohol used
can contribute to hemolysis.
◆ Do not collect a specimen from an area of the arm that has
a hematoma.
◆ Consider discarding specimens if the blood enters the tube
too slowly or if accessing the vein was difficult. Both these
scenarios often result in damage to the red blood cells and
hemolysis. If good blood flow is established, collect another
sample from the same site and discard the first sample. If
good blood flow cannot be established, select a new
venipuncture site.
Tube Top Colors: Additives and Uses
Common Blood Collection
Red Marble Top or Gold
(Clot activator and gel
for serum separation)
Light Blue
(Sodium Citrale
(Sodium Heparin or
Lithium Heparin
Lavender (EDTA
teraacetic acid)
Gray (Patassium
Oxalater sodium
Fluoride or  sodium
Yellow Marble Top
or Orange
Light Green
Lithium heparin and
gel for plasma
(Sodium Heparin
(glass tubes)
EDTA (plastic))
Royal Blue
(Sodium Heparin
EDTA None)
Color (Additive Color (Additive
Tube Top  Colors: Uses
Examples of Common Labs
Blood bank, type and cross, or used as a discard tube
Red Marble-top or Gold:
Chemistry, Ca, BUN, creatinine
Light Blue:
Coagulation studies, PT, PTT, INR, fibrinogen
Hematology, CBC, H&H platelet counts
Chemistry, blood glucose
Chemistry ionized Ca
Urine Sample Collection
Random Urine Collection
■ If time permits, collect the first voided specimen of the morning.
■ Collect the specimen in a nonsterile container with a screw top
■ If the specimen cannot be sent to the lab immediately, refrigerate
until taken to the lab.
■ Specimens can be refrigerated for 24 hr. They should be received
in the laboratory within 1 hr of removal from refrigeration.
Clean Catch Midstream Urine Collection
Female Patients
Tell the patient to:
■ Wash her hands well, remove the lid from the collection cup, and
open the towelette package.
■ Separate the labia and keep the labia separated until the urine is
■ Cleanse the meatus with one towelette using a front to back
■ Repeat with next towelette.
■ Keep the labia separated and begin to urinate into the toilet.
■ Move the collection cup into the urinary stream making sure the
cup does not come in contact with clothing, legs, or genitals.
■ Fill the container halfway, remove the cup from the urinary
stream, and finish voiding into the toilet.
■ Wash her hands, replace the lid on the container, and dry the
outside of the container.
Male Patients
Tell the patient to:
■ Wash his hands well, remove the lid from the collection cup, and
open the towelette package.
■ Pull back the foreskin, if present, to expose the urinary meatus.
■ Wash the meatal opening with the towelette using a circular
■ Repeat with the remaining towelettes.
■ Begin voiding into the toilet.
■ Move the collection cup into the urinary stream making sure the
cup does not come in contact with clothing, legs, or genitals.
■ Fill the container halfway, remove the cup from the urinary
stream, and finish voiding into the toilet.
■ Wash his hands, replace the lid on the container, and dry the
outside of the container.
Urine Collection from a Closed Urinary Drainage System
■ Wash hands.
■ Clamp the drainage tubing below the port.
■ Obtain gloves, syringe, needle, alcohol wipe, and collection cup.
■ Label collection container.
■ Don gloves and clean the port with an alcohol swab.
■ Insert the needle into port and aspirate at least 10 mL of urine.
■ Transfer the urine from the syringe into the specimen cup.
■ Unclamp the catheter.
■ Discard needle in sharps container. Wash hands.
■ Send the specimen to the lab
Timed Urine Specimen Collection (2-, 6-, 12-, or 24-Hr Urine)
■ Urine samples collected over a specific period of time are called
timed specimens.
■ Times may be as short as 2 hr or as long as several days.
■ At the start of the collection, have the patient void and discard
this urine sample. This is the start time and should be noted on
the time on the collection container. For 24-hr urines, this ideally
would be the first void of the morning.
■ Collect all urine from that point onward for the specified period
of time. Unless instructed otherwise, keep the urine refrigerated
or on ice in the bathroom.
■ At the end of the time period, void and add this specimen to the
container. Note the time of the lasted voided urine. If collecting a
24-hr urine sample, the last urine collected should be voided at
the exact same time as the first urine was discarded.
■ Once the collection time period is complete, send the urine to
the lab immediately.
■ Note that usual fluid intake is allowed during the urine collection
period; however dietary restrictions may apply. (Check with lab.)
Respiratory Secretions Collection
Nasopharyngeal or oropharyngeal swabs or sputum specimens
may be collected for viral and/or bacterial diagnostic testing.
Nasopharyngeal or Oropharyngeal Swabs
■ Nasopharyngeal swabs: Insert a swab into the nostril parallel to
the palate. Leave the swab in place for a few seconds to absorb
secretions. Swab both nostrils.
■ Oropharyngeal swabs: Swab the posterior pharynx and tonsillar
areas, avoiding the tongue.
■ If using a culturette swab, insert into plastic container and break
the seal that releases the viral transport media. If culturette
swabs are not available, place the swabs immediately into sterile
vials containing 2 mL of viral transport media. Break the
applicator sticks off near the tip to permit tightening of the cap.
■ Label each specimen container and send to the lab.
Sputum Sample
■ Explain to the patient the difference between sputum and oral
secretions. Only a small amount of sputum is required, but it
must be sputum and not saliva.
■ Have the patient rinse his or her mouth with water (to help
reduce contamination by normal oral flora).
■ Tell the patient to take three or four deep breaths and cough
lightly to help raise secretions from the bronchial tree.
■ Next have the patient cough forcefully and directly into a sterile
screw-cap sputum collection cup or sterile dry container.
■ Label the specimen and send to the lab.
■ If the patient is unable to raise a sputum sample, the sample
may be obtained by the following means:
◆ Induced sputum: must be ordered by physician, usually done
by a respiratory therapist. Deep coughing is induced by
◆ Bronchial washings: done by the physician during a
Normal Flora
Microbiology reports identify the disease-causing organisms
from cultures. Many organisms are found in different body
sites, but do not produce disease (unless there is an abnormally
high amount). The microbiology report may say “normal flora”
to mean that no disease-producing organism was found, or it
may list all organisms found and not distinguish which are
normal flora.  The following list identifies organisms that
normally live in and on the body.
■ Alpha hemolytic streptococci
■ Coagulase-negative staphylococci
■ Bacillus species
■ Corynebacteria species
■ Alpha hemolytic streptococci (not Enterococcus)
■ Nonhemolytic streptococci
■ Corynebacteria species
■ Neisseria species
■ The following pathogens may be part of the routine flora if
they do not predominate:
◆ Coagulase-negative staphylococci
◆ Haemophilus influenzae
◆ Haemophilus parainfluenzae
◆ Moraxella catarrhalis
◆ Neisseria meningitidis
◆ Streptococcus pneumoniae
■ Alpha hemolytic streptococci (not Enterococcus)
■ Nonhemolytic streptococci
■ Coagulase-negative staphylococci (if not predominating)
■ Corynebacteria species
■ Lactobacilli
Safety Issues When Collecting Specimens
The OSHA (Occupational Safety and Health Act) Bloodborne
Pathogens Standard mandates that all laboratory specimens be
treated as potentially infectious. Follow these guidelines to
minimize exposure and spread of organisms:
■ Wear gloves whenever there is potential for exposure to
blood, body fluids, or tissue specimens.
■ Use goggles, gown, and mask in areas where contact with
aerosols or large amounts of body fluids may occur (for
example, in the OR, procedure room, or emergency
■ Do not recap or cut needles prior to disposal. Always discard
needles in the proper needle-disposal containers. Do not
remove safety needles from collection tube holders. Dispose
of holder and needle.
■ Wash hands frequently!
■ Tightly cap all specimen containers to prevent leakage or
■ Make sure specimen container is not leaking or cracked. If it
is, place in another container before sending to lab.
■ Before sending specimens to the lab, place collection
container in a sealed bag labeled with a biohazard sticker.
■ Make sure laboratory requisition forms are not contaminated.
If they are, prepare new ones.
■ Consider a hepatitis B virus vaccination. It is recommended
for health care personnel in contact with patients and body
Physiologic Changes in Older Adults
Changes in Lab Values in Older Adults
Laboratory Values Age-associated Change
Alkaline phosphatase
Serum albumin
Serum magnesium
Uric acid
Total cholesterol
HDL cholesterol
Fasting blood glucose
2-hr postprandial blood
Creatinine clearance
Leukocyte count
(erythrocyte sedimenta-tion rate)
Source: Brigden ML, Heathcote JC. (2000). Problems in interpreting
laboratory tests. What do unexpected results mean? Postgraduate
Medicine 107(7). http://www.postgradmed.com/issues/2000/06_00/brigden.
htm. Accessed 9/22/04
↑ up to 20% in men and up to 37%
in women
Slight ↓
↓ 15%
Slight ↑
↑ 30–40 mg/dL by age 55 in women
and age 60 in men
↑ 30% in men and ↑ 30% in women
between ages 30 and 80
↑ 30% in men and 50% in women
between ages 30 and 80
↑ 2 mg/dL per decade after age 30
↑ up to 100 mg/dL plus age in years
after age 40
↓ 25% between ages 30 and 80
↓ 10 mL/min/1.73 m3
per decade
Slight ↓
↑ (upper limit 40 mm/hr in men and
45 mm/hr in women)
Abbreviations Used in Lab Results
 less than
 greater than
c centi (102
or 0.01)
CrCl creatinine clearance
d deci (101
or 0.1)
dL deciliter
Eq equivalents
f femto (1015
g or gm gram
gm/dL grams per deciliter
IU International Unit
kkilo (103
or 1000)
L liter
m milli (103
or 0.001)
mEq milliequivalent
mg milligram
mc or  micro (106
mmol millimole
mol mole
mOsm milliosmoles
n nano (109
Osm Osmoles
ppico (1012
Reference Ranges Explained
■ A reference range for any given test is the average of the
results from a large population of healthy individuals plus or
minus 2 standard deviations.
■ Reference range rather than normal range is the preferred
■ Many factors, including the reagents and equipment used by
different labs, influence reference ranges and each lab must
establish its own reference ranges.
■ Only a few analytes (i.e., substances that are analyzed)
have nationally standardized testing methods and report
■ Glucose, cholesterol, and prostate-specific antigen are three
commonly performed tests that have been standardized.
■ In most cases, the patient’s result must be compared to the
reference range supplied by the laboratory that ran the test for
accurate interpretation.
■ Labs also use different units of measure to report many test
Reusable Lab Test Results Forms
Blood Chemistry Screen/Metabolic Panel
Patient’s Name:
Date/Time Date/Time
ALP (alkaline phosphatase)
ALT (alanine
AST (also called SGOT)
Bilirubin, total
BUN (blood urea nitrogen)
Protein, total
Hematology Panel
Patient’s Name:
Date/Time Date/Time
Neutrophils, bands
Neutrophils, segmented
Cardiac Biomarkers
Patient’s Name:
Date/Time Date/Time
CK (creatine
Troponins (TnI/TnT)
Myoglobin, serum
ACB (albumin cobalt
BNP (B-type natriuretic
*May be called IMA for ischemia-modified albumin.
Coagulation Profile
Patient’s Name:
Date/Time Date/Time
Fibrin split products
ABG Results
Patient’s Name:
Date/Time Date/Time
(80–100 mm Hg)
(35–45 mm Hg)
O2 Saturation
(21–28 mEq/L)
Base Excess
(2 to 2 mEq/L)
Quick ABG Interpretation
Respiratory acidosis ↓↑ or normal ↑
Compensated normal  ↑↑
or slightly ↓
Respiratory alkalosis ↑↓ or normal ↓
Compensated normal  ↑↑
or slightly ↓
Metabolic acidosis ↓↓ ↓ or normal
Compensated normal ↓↓
or slightly ↓
Metabolic alkalosis ↑↑↑ or normal
Compensated normal ↑↑
or slightly ↓

Normal Rate   60–100 bpm  0.04 sec
Normal P-R   0.12–0.20 sec  0.20 sec
Normal QRS   0.08–0.12 sec
P wave    atrial depolarization; QRS    ventricular
depolarization; T wave   ventricular repolarization
P-R interval

Rate…………………………………………………………… Between 60–100
Rhythm …………………………………………………………………… Regular
P waves………………………………………………………………….. Present
P-R …………………………………………………………………………. Normal
QRS………………………………………………….Normal (0.08–0.12 sec)
P waves before every QRS, P-R <0.20
Quick ECG Interpretation
Normal Sinus Rhythms
Basic ECG Assessment
Follow these steps for basic electrocardiogram interpretation.
1. Determine ventricular rate.
2. Determine QRS duration and shape.
3. Identify P waves and determine if a P wave precedes every
QRS complex.
4. If more than 1 P wave precedes a QRS complex, determine
ratio of P waves to QRS complex (ex., 4:1, 3:1, 2:1).
5. Is P wave shape consistent?
6. Determine atrial rate and rhythm.
7. Determine P-R intervals and if they are consistent.
Analyzing the P-R Interval (PRI)
•PRI is consistent and between 0.12 and 0.20 sec (3–5 small
boxes): This is considered a normal PRI.
• PRI is 0.12 sec (3 small boxes): consider junctional rhythm.
•PRI is longer than 0.20 sec (5 small boxes), it remains
consistent in length from PRI to PRI: Consider 1 AV block.
• PRI undergoes progressive lengthening until a QRS is dropped:
Consider 2 AV block, type I.
• PRI is consistent; however, there are additional P waves that
do not preceed a QRS complex: Consider 2 AV block, type II.
• PRI is not consistent, nor is there any correlation between the
P wave and the QRS: Consider 3 AV block (CHB).
Analyzing the QRS Complex
•QRS between 0.08 and 0.12 (2–3 small boxes): Consider
• QRS 0.12 sec, “wide and bizarre”: Consider ventricular
• QRS 0.12 sec (3 small boxes), with notched or “rabbit ears”
appearance: Consider BBB.
• QRS preceded by 1–2 very narrow “spikes”: Think pacemaker.
Selected References
Brigden ML, Heathcote JC. (2000). Problems in interpreting
laboratory tests. What do unexpected results mean?
Postgraduate Medicine Online Vol 107, No 7.
Cavanaugh B (2003). Nurse’s Manual of Laboratory and
Diagnostic Tests. Philadelphia: FA Davis Company.
CDC. Severe Acute Respiratory Syndrome (SARS) Public Health
Guidance for Community-Level Preparedness and Response to
Severe Acute Respiratory Syndrome (SARS). (2004, June 8).
Supplement F: Laboratory Guidance. Version 2. Appendix
F4— Guidelines for Collecting Specimens from Potential SARS
FDA. T03-14 (2003). Talk Paper Clears New Lab Test to Help Rule
Out Heart Attack. http://www.fda.gov/bbs/topics/ANSWERS/
Fogoros RN (2004). Cardiac MRI — Ready for prime time? Heart
Disease / Cardiology. http://heartdisease.about.com/library/
Gosbee J, DeRosier J (2004). MR Hazard Summary. The National
Center for Patient Safety (NCPS). http://www.patientsafety/
Hash R. (1999). Intravascular radiographic contrast media: issues
for family physicians. J Am Board Fam Pract 12(1):32–42.
Hoeffner EG et al. (2004). Cerebral perfusion CT: technique and
clinical applications. Radiology 231:632–644.
Maddox TG. (2002). Adverse reactions to contrast material:
recognition, prevention, and treatment. Am Fam Physician
Mylonakis E. (2001). Plasma Viral Load Testing in the
Management of HIV Infection
Am Fam Physician 3:483–490. http://www.aafp.org/afp/20010201/
National Cancer Institute (2002). Radiation Risks and Pediatric
Computed Tomography (CT): A Guide for Health Care
OSHA. Safety and Health Bulletin 10-15-03. (2003). Disposal
of Contaminated Needles and Blood Tube Holders Used
for Phlebotomy. http://www.osha.gov/dts/shib/shib101503.html
RSNA News (2004, August). Patients and Physicians Uninformed
About CT Risks. http://www.rsna.org/publications/rsnanews/
Schnell, ZB et al. (2003). Davis’s Comprehensive Handbook of
Laboratory and Diagnostic Tests. Philadelphia: FA Davis
Schnitker, JB,  Light, DW (2001).Nonneurologic indications for
MRI: Technological advances have broadened applications.
Postgraduate Medicine Online Vol 109, No 6. http://www.
Smeltzer S, Bare B (2004). Brunner and Suddarth’s Textbook of
Medical Surgical Nursing. 10th ed. Philadelphia: Lippincott
Williams & Wilkins.
Taylor RL et al (2002). Validation of a high-throughput liquid
chromatography–tandem mass spectrometry method for
urinary cortisol and cortisone. Clin Chem  48:1511–1519.
Illustration Credits
Pages 64, 65, 66, 67, 70, 72, 77, 135, 151 from: McKinnis, L,
Fundamentals of Orthopedic Radiology, FA Davis, Philadelphia,
PA ,  1997
Page 74 from: Taber’s Cyclopedic Medical Dictionary, FA Davis,
Philadelphia, PA, 1997
Page 138 from: Cavanaugh B (2003). Nurse’s Manual of
Laboratory and Diagnostic Tests. Philadelphia: FA Davis
Pages 183, 184 courtesy of Ehren Myers, R.N.
Page 121 from: Atlas of Clinical Neurology, Edition 2.
Philadelphia: Current Medicine
Page 147 from: Atlas of Heart Disease, Volume 1, Edition 4.
Philadelphia: Current Medicine
Page 118 from: Atlas of Cardiac Imaging, Volume 1, Edition 3.
Philadelphia: Current Medicine
Page 160 from: Atlas of Anesthesia, volume 4, Edition 1.
Philadelphia: Current Medicine
Page 84  from: Atlas of Rheumatology, Edition 3. Philadelphia:
Current Medicine
A/G Ratio, 3
A1C, 33
laboratory results, 191
obstruction series, 75
plain film, 68
Abdominal flat plate, 68
Abdominal/pelvic computed
tomography, 117–118
ABGs, 7
ABI, 146
ACB Test,  2
Acid-fast bacillus stain, 1
Acid phosphatase, 1
ACP, 1
ACTH stimulation test, 1
Activated partial thromboplas-tin time, 2
tube top colors, 183–184
myocardial perfusion scan,
162, 163
ADH suppression test, 5
Adrenal glands
magnetic resonance imag-ing, 133
Adrenocorticotropic hormone,
AFB, 1
AFP, 3
AG, 4
Agglutinin titer
febrile, 30
Alanine aminotransferase, 2
Albumin, 2
urine, 42
Albumin cobalt binding test, 2
Albumin/globulin ratio, 3
Albumin to creatinine ratio,
serum, 3
urine, 3
Alkaline phosphatase, 3
ALP, 3
Alpha-fetoprotein, 3
ALT, 2
Ammonia, 4
serum, 4
Anaphylactoid reaction
iodinated contrast media,
Anechoic tissues, 137
Anemia types, 20
Angiogram, 85–87, 119–120
radionuclide, 161
computed tomography, 109,
magnetic resonance, 128,
Anion gap, 4
ANP, 1
auto, 4–5
Antidiuretic hormone, 5
direct, 21
indirect, 21
Antimicrosomal antibody, 53
Antiplatelet antibodies, 45
Antistreptolysin O/antistrepto-coccal O titer, 5
Antithrombin III, 2
Antithyroglobulin antibody, 53
Apo A-1, 6
Apo B, 6
lipoprotein (a), 6
Arterial blood gases
base excess/deficit, 7–8
HCO3, 7–8
O2 saturation, 7–8
PaCO2, 7–8
PaO2, 7–8
pH, 7–8
quick interpretation
reusable results form, 195
Arterial duplex scan, 146
Arteriogram, 85–87
Arteriography, 85–87
Arthrography, 83–84
Arthroscopy, 168
ASO, 5
Aspartate aminotransferase, 9
AT-111 ,  2
A-type natriuretic peptide, 1
Autoantibody test, 21
Barium enema, 88–89
Barium swallow, 90
Bence Jones protein, 9
Biliary system
magnetic resonance imag-ing, 133
total, direct, indirect, 9–10
urine, 10
Biopsies, 168
ultrasound, 148
Bleeding time, 10
fecal occult, 30
Blood alcohol, 30
Blood chemistry screen/meta-bolic panel
reusable results form, 192
Blood count
with differential, 19–20
Blood cultures, 10
Blood gases
arterial. see Arterial blood
Blood urea nitrogen, 10–11
BMD, 69
bone scan, 151, 153
Body computed tomography,
x-rays, 73
x-rays, 69–70
Bone densitometry, 69
Bone mineral density, 69
Bone scan
whole body, 151, 153
computed tomography,
computed tomography,
FDG scan, 154
magnetic resonance imag-ing, 133
positron emission tomogra-phy, 154
SPECT scan, 155–156
Brain perfusion study,
ultrasound, 148
x-rays, 74
Bronchial washings, 187
Bronchoscopy, 169
B-type naturiuretic peptide,
BUN, 10
C. difficile toxin, 11
CA 125, 12
CA 15–3, 11
CA 19–9, 12
Cachectin, 55
Calcitonin, 12
ionized, 12
total, 13
Captopril renal scan, 164
Carbon dioxide content, 13
Carbon monoxide, 13
Carboxyhemoglobin, 13
Carcinoembryonic antigen,
Cardiac biomarkers, 14
reusable results form, 194
Cardiac blood pool scan, 161
Cardiac catheterization, 169
Cardiac magnetic resonance
imaging, 136
Cardiac scans, 165
myocardial perfusion scan,
Cardiovascular reaction
iodinated contrast media, 82
Carotid arteriogram, 84
Carotid duplex scan, 146, 147
Catecholamines, 14
CBC with diff, 19
CD4/CD8 ratio, 11, 41
CD4 marker, 41
Cerebral arteriogram, 85
Cerebrospinal fluid analysis,
computed tomography, 123
magnetic resonance imag-ing, 133
Chest x-ray, 71
abnormal, 72
with anatomic landmarks, 72
Chlamydia group antibody, 16
Chloride, 16
operative or T-tube, 98–99
percutaneous transhepatic,
10 0–101
approach, 102
endoscopic retrograde, 171
magnetic resonance, 133
oral, 99–100
Cholescintigraphy, 166
total, 16
x-rays, 70
Coagulation factors, 17
Coagulation profile
reusable results form, 194
Coagulation system
extrinsic, one-stage assay,
intrinsic, one-stage assay, 17
Cold agglutinin titer, 18
Colonoscopy, 169
Colposcopy, 170
C3 and C4, 18
total, 18
Complete blood count
with differential, 19–20
Computed tomography,
abdominal/pelvic, 117–118
brain, 120–122
cerebral perfusion imaging,
chest, 123–124
contrast agents, 114–115
CT scanner
description, 110
exterior, 111
interior, 111
3D-CT scan, 110
fluoroscopic, 109
image, 112
IV contrast, 115
oral contrast, 115
overview, 109
patient preparation, 116
positron emission, 152
radiation exposure, 114
rectal contrast, 115
single photon emission, 152
skeletal, 124–125
spinal, 125–126
views, 113
whole body, 127
xenon, 114–115
Computed tomography
angiography, 109, 119–120
Computed tomography myel-ography, 95–96
Computed tomography scan-ner, 110, 111
Contraction stress test, 172
Contrast agents, 78, 79
computed tomography,
echocardiograms, 140
adverse reactions, 80–82
magnetic resonance imag-ing, 131
Contrast-mediated x-rays,
adverse reactions, 78–79
prevention strategies,
risk factors, 79
contrast agents, 78
osmolality, 78–79
Coombs’ test
direct, 21
indirect, 21
Core biopsy, 168
Corticosteroids, 39
free, 21
plasma, 21
Cosyntropin stimulation test,
CPK isoenzymes, 22
C-reactive protein, 11
Creatine kinase, 22
serum, 22
urine, 22
Creatinine clearance, 23
Creatinine phosphokinase, 22
CRP, 11
Cryoglobulins, 23
CSF Analysis, 15
Cystatin C, 23
Cystine, 23
Cystogram, 91
Cystography, 91
Cystometrogram, 170
Cystourethrogram, 91
Cytomegalovirus antibodies,
D-dimers, 24
Delayed reaction
iodinated contrast media, 82
DEXA scan, 69
Dexamethasone suppression
test, 24
Diagnostic testing
general preparation, 176
Digital subtraction angiogra-phy, 85
myocardial perfusion scan,
162, 163
myocardial perfusion scan,
162, 163
Dobutamine stress echocar-diogram, 144
Doppler ultrasound, 138, 145
bedside, 145
color, 145
continuous-wave, 145
power, 138
transcranial, 138
Drug levels
therapeutic and toxic
conventional measure-ments, 25–26
SI units measurements,
Drug monitoring
therapeutic, 28
Dual-modality PET/CT, 152
Duplex scans, 138, 145. see
also Doppler ultrasound
carotid, 146, 147
vascular, 146
Echocardiograms, 196, 197
dobutamine stress, 144
echocardiogram contrast,
overview of, 140
transesophageal, 142–143
transthoracic, 141, 143
Echocardiography, 137
Electroencephalogram, 170
serum, 28
sweat, 51
urine, 29
Electromyogram, 171
Electrophysiology study, 171
Endocrine scans, 166
Endoscopic biopsy, 168
Endoscopic retrograde cholan-giopancreatography, 171
Enteroclysis, 92–93
increased, 60
EPO, 29
Erythrocyte sedimentation
rate, 49
Erythropoietin, 29
Esophageal function studies,
Esophagogastroduodeno-scopy, 172
Esophagography, 90
ESR, 49
serum, 29
Estrogen fraction, 29
Ethanol, 30
EU, 105
Evoked potential studies,
Excisional biopsy, 168
Excretory urogram, 105–106
ExU, 105
fecal, 30
FDG-PET, 152
parathyroid, 166
FDG-positron emission
tomography scan, 165
FDP, 31
Febrile agglutinin titer, 30
Fecal fats, 30
Fecal lipids, 30
Fecal occult blood, 30
Ferritin, 30–31
Fetal monitoring, 172
external, 172
internal, 172
a-Fetoprotein, 3
Fibrin degradation products,
Fibrin split products, 31
Fibrinogen, 31
Fine needle aspiration, 168
x-rays, 70
First-pass study, 165
normal, 188
urine, 170
Fluorine-18 -labeled fluo-rodeoxyglucose
brain scan, 154
Fluoroscopic computed
tomography, 109
Folate, 31
Folic acid, 31
Follicle-stimulating hormone,
x-rays, 70
reusable lab test results,
Free thyroxine, 52
FSH, 31
Furosemide renal scan, 164
G-6-PD assay, 33
Gallium scan, 156
Gamma-glutamyl transpepti-dase, 32
Gastric emptying scan, 157
Gastric mucosal imaging,
Gastrin, 32
Gastroesophageal reflux scan,
Gastrointestinal bleeding
scan, 157–158
Gastrointestinal scans,
Genitourinary tract
flora, 188
GGT, 32
GHb, 33
Glucagon, 32
x-ray reactions, 80–82
fasting, 32
Glucose-6-phosphate dehy-drogenase screening test,
Glucose tolerance test
standard oral, 33
Glycohemoglobin, 33–34
Glycosylated hemoglobin,
Growth hormone, 34
Growth hormone stimulation
test, 34
Growth hormone suppression
test, 34
Guthrie test, 44
x-rays, 70
Haptoglobin, 34
HBA1, 33
Hct, 34
HDL Cholesterol, 16
Helicobacter pylori antibody
titers, 34
Helicobacter pylori breath
test, 167
Hematocrit, 34–35
Hematology panel
reusable results form, 193
Hemoglobin, 35
glycosylated, 33–34
Hemoglobin electrophoresis,
Hemoglobinopathy profile, 35
Hemolysis, 182
Hepatic arterial perfusion
scan, 166
Hepatitis testing, 36
Hepatobiliary scans, 166–167
total, A, A and B, 36
Hgb, 35
Hgc, 37
High-density lipoprotein
cholesterol. see Cholesterol
High-sensitivity CRP, 11
HLA, 37
Holter monitor, 173
Homocysteine, 36
hs CRP, 11
Human chorionic
serum, 37
Human growth hormone, 34
Human immunodeficiency
virus testing, 37
Human leukocyte antigens, 37
5-Hydroxyindoleacetic, 37
Hyperechoic tissues, 137
Hypoechoic tissues, 137
Hysterosalpingogram, 93–94
IMA, 2
Immunofixation, 9
Immunoglobulins, 38
Incisional biopsy, 168
Infarct avid PYP scan, 165
International normalized ratio
(INR), 38, 48. see
Prothrombin time
Ionizing radiation, 128
Iron tests, 38
Ischemia-modified albumin,
IV infusion set
venipuncture, 181
IV urogram, 105–106
IVP, 105
computed tomography,
x-rays, 73
, 46
17-Ketogenic steroids, 39
17-Ketosteroids, 39
magnetic resonance imag-ing, 134
ultrasound, 148
Laboratory results
abbreviations, 191
Laboratory tests
reference ranges, 191
reusable results forms,
Laboratory values
older adults, 190
Lactate, 39
Lactate dehydrogenase, 39
Lactic acid, 39
Laparoscopic biopsy, 168
LDH isoenzymes, 39
LDL, 41
LDL Cholesterol, 16
Lead, 40
Legionnaire’s antibody test, 40
LFTs, 40
Lipase, 40
fecal, 30
Lipoproteins. see individual
magnetic resonance imag-ing, 134
nuclear medicine scans,
Liver/biliary system
ultrasound, 148
Liver function tests, 40
Low-density lipoprotein. see
Lower extremity arteriogram,
Lung scan, 159–160
Luteinizing hormone, 41
Lyme disease antibody, 41
radionuclide, 167
Lymphocyte assay, 41
Lymphocyte immunopheno-typing, 11
decreased, 60
increased, 59
MA, 42
serum, 41
Magnetic resonance angiogra-phy, 128, 134
Magnetic resonance cholan-giopancreatography,
Magnetic resonance image
example, 135
Magnetic resonance imaging,
adrenal glands, 133
biliary system, 133
brain, 133
cardiac, 136
chest, 133
contrast agents, 131
functional, 128
functioning, 129
kidney, 134
liver, 134
musculoskeletal, 134
overview, 128
patient preparation, 132
posttest care, 132
procedure, 132
safety issues, 130
spine, 134
uses, 128
vascular system, 134
Magnetic resonance spec-troscopy, 128
Mammography, 74
x-rays, 70
Meckels scan, 166
x-ray reactions, 80–82
Methemoglobin, 42
Microalbumin, 42
increased, 60
Multigated blood pool imag-ing, 161
Musculoskeletal system
magnetic resonance imag-ing, 134
ultrasound, 148
Myelogram, 95–96
medications withheld for 48
hours, 97
Myocardial perfusion scan,
exercise, 162–163
persantine, adenosine, or
dobutamine, 162, 163
resting, 162, 163
serum, 42
urine, 43
Nasopharyngeal swabs, 187
Naturiuretic peptide
A-type, 1
B-type, 9
Needle biopsy, 168
Nephropathic reaction
iodinated contrast media,
decreased, 60
increased, 59–60
Nipple stimulation test, 172
Nonstress test, 172
Nuclear medicine scans
bone, 153
brain, 154–156
cardiac, 165
disease shown, 150
endocrine, 166
gallium, 156
gastric emptying, 157
gastrointestinal bleeding,
GI and hepatobiliary,
liver/spleen, 158
lung, 159–160
multigated blood pool imag-ing, 161
overview, 150
safety issues, 151
techniques, 152
tumor/infection, 167
5-Nucleotidase, 43
ultrasound, 149
Obstruction series, 75
Occupational Safety and
Health Act
bloodborne pathogens stan-dard, 189
Octreotide scan, 167
Older adults
laboratory values changes,
physiologic changes, 190
Oncoscint scan, 167
Orbital x-rays, 75
Oropharyngeal swabs, 187
serum, 43
urine, 43
Osteopenia, 69
Oximetry, 173
Oxytocin challenge test, 172
Paranasal sinuses x-rays, 76
Parathormone, 43
FDG-positron scan, 166
Parathyroid hormone, 43
Partial thromboplastin time,
Parvovirus B19 antibody, 44
ultrasound, 149
Perfusion computed tomogra-phy, 122
Peritoneal shunt evaluation,
myocardial perfusion scan,
162, 163
brain, 154
Phenylketonuria test, 44
Phosphate, 44
serum, 44
PKU Test,  44
Plasma renin activity, 48
Plasma viral load, 58
Plasminogen, 45
Platelet antibodies, 45
Platelets, 45
PO4, 44
urine, 46
Positron emission computed
tomography, 152
Positron emission tomogra-phy
brain, 154
serum, 46
Prealbumin, 46
Pretest preparation, 176
Progesterone, 47
ultrasound, 149
Prostate-specific antigen, 47
Prostatic acid phosphatase, 1
urine, 48
Protein electrophoresis, 9, 47
Prothrombin time, 48
PSA, 47
Pseudomembranous colitis
toxic assay, 11
PT, 48
PTT, 44
Pulmonary arteriogram, 85
Pulmonary function tests,
PVL, 58
procedure and care, 103
intravenous, 105–106
procedure and care, 104
Radioactive isotope, 150
Radionuclide angiogram, 161
Radionuclide lymphan-giogram, 167
Radiopharmaceutical, 150
Rapid plasma reagin, 57
Renal arteriogram, 85
Renal perfusion scan, 164
Renal scintigraphy, 164
Renin, 48
Renogram, 164
Resin T3 uptake, 51
Respiratory flora, 188
Respiratory secretions
collection, 187
Reticulocyte count, 48
RF, 49
Rheumatoid factor, 48
Rotavirus antigen, 49
RPR, 57
RT3U, 51
serum, 49
x-rays, 70
Schilling’s test, 167
abdominal/GI, 157–158
renal, 164
ultrasound, 149
Sedimentation rate, 49
Serum iron, 38
Serum transferrin, 38
Sestamibi scan, 162–163
SGGT, 32
Sickle cell screening test, 35
Single photon emission
computed tomography, 152
brain, 155–156
Skeletal computed tomogra-phy, 124–125
Skin flora, 188
Skin puncture
blood analysis, 181–182
x-rays, 76
Small bowel enema, 92–93
serum, 50
urine, 29
Somatotropin hormone, 34
Sonogram, 137
safety issues, 189
SPECT. see Single photon
emission computed tomog-raphy
magnetic resonance, 128
Spinal computed tomography,
Spinal x-rays, 77
magnetic resonance imag-ing, 134
with flow volume loops, 173
nuclear medicine scans, 158
induced, 187
Sputum culture and sensitiv-ity, 50
Sputum sample, 187
Stool culture, 50
Stool for occult blood, 30
Stool for ova and parasites, 50
Stress thallium scan, 162–163
Sweat electrolytes, 51
venipuncture, 181
free, 52
total, 51
T3 radioimmunoassay, 51
T3 resin uptake, 51
Tagged RBC liver/spleen scan,
Tagged red blood cell scan,
Testosterone, 52
myocardial perfusion scan,
myocardial perfusion scan,
Thoracoscopic biopsy, 168
Throat and nares culture, 52
tissue, 17
ultrasound, 149
Thyroid antibodies, 53
Thyroid function tests, 52–53
Thyroid scan, 166
Thyroid-stimulating hormone,
free, 52
Thyroxine screen, 51
TIBC, 38
Tilt table test, 175
Tissue factor, 17
TNF-a, 55
Tnl, 54
TnT, 54
To e
x-rays, 70
TORCH screen, 53
Total iron binding capacity, 38
Tracer, 150
Transcranial Doppler ultra-sound, 138
Transesophageal echocardio-gram, 142–143
Transferrin, 53
Transferrin saturation, 38
Transthoracic echocardio-gram, 141, 143
Treadmill-Mibi, 162–163
Triglycerides, 54
Triiodothyronine, 51
Triple screen test, 175
Troponins, 54
TSH, 53
Tube top colors
additives and uses, 183–184
Tuberculosis culture, 54
Tumor necrosis factor-a, 55
UA, 56
Ultrasound, 137–149
3-D, 137, 138
abdominal, 148
bladder, 148
breast, 148
conventional, 137
Doppler. see Doppler ultra-sound
kidney, 148
liver/biliary system, 148
musculoskeletal, 148
obstetric, 149
overview, 137–138
pelvic, 149
posttest care, 139
pretest preparation, 139
procedure, 139
prostate, 149
scrotal or testicular, 149
thyroid, 149
vascular, 137, 145–147
Upper GI series, 106–107
Urea breath test, 167
Uric acid
serum, 55
urine, 55
Urinalysis, 56
Urinary drainage system
urine collection, 186
electrolytes, 29
Urine albumin, 42
Urine culture and sensitivity,
Urine flowmetry, 170
Urine sample collection,
clean catch midstream,
closed urinary drainage
system, 185–186
random, 185
timed, 186
Urobilinogen, 57
Urodynamic studies, 170
Vanillylmandelic acid, 14
Vascular system
magnetic resonance imag-ing, 134
Vascular ultrasonography, 137,
VDRL, 57
Venereal diagnosis research
laboratory, 57
Venipuncture procedure
bleeding control, 180
butterfly method, 177
equipment, 177
evacuated collection tube
engagement, 180
evacuated tube system,
IV infusion set, 181
methods, 177, 181
needle disposal, 180
needle removal, 180
patient identification, 177
performance, 178
site preparation, 178
site selection, 178
specimen labeling, 180
syringe method, 177, 181
technique, 179
lower extremity, 108
Venous duplex scan, 146
Ventilation and perfusion lung
scans, 159–160
Ventriculogram, 161
Very low-density lipoprotein
cholesterol (VLDL), 16
Viral culture, 57
Viral load, 58
Vitamin B12, 58
VMA, 14
Voiding cystourethrogram, 91
West Nile virus, 58
White blood cell count and
differential, 59–60
White blood cell scan, 167
Wound culture, 60
obstruction series, 75
anterior oblique positions,
anterior-posterior position,
basic positions, 63
bone, 69–70
breasts, 74
chest, 71
abnormal, 72
with anatomic landmarks,
contrast-mediated. see
Contrast-mediated x-rays
general description and
process, 62
joints, 73
lateral positions, 65
long bone, 73
orbital, 75
paranasal sinuses, 76
plain, 68–77
abdominal, 68
patient preparation, 68
posterior-anterior position,
posterior oblique positions,
radiodensity, 62
skull, 76
spinal, 77
terms, 63
Xylose tolerance test, 61

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