Carcinoembryonic Antigen
Test Description
Carcinoembryonic antigen (CEA) is a glycoprotein that is normally produced by the
fetus and secreted by gastrointestinal cells. In adults, it is normally found in trace
amounts. However, CEA tends to increase in the case of malignancies. It is primarily
nonspecific and thus is not used alone in cancer diagnosis. This test has been
found to be effective in the early detection of colorectal cancer, with CEA levels rising
several months before clinical symptoms appear. Smaller tumors found early in
development will have low or normal CEA levels, whereas advanced or metastatic
conditions are likely to have higher CEA levels. Measurement of CEA levels can also
be helpful monitoring the response of the patient to cancer treatment, and for monitoring
the patient for recurrence of cancer.
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THE EVIDENCE FOR PRACTICE
• Drawing a CEA level has been recommended before and every 3 months for the first
2 years after resection of colorectal cancer.
• Postoperative return to normal of an elevated preoperative CEA is associated with
complete tumor resection, whereas persistently elevated values indicate the presence
of residual disease.
• Elevated preoperative CEA levels have been found to be an independent predictor
of poor outcome.
ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Normal Values
Nonsmoker: <3 ng/mL (<3 mcg/L SI units)
Smoker: <5 ng/mL (<5 mcg/L SI units)
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Possible Meanings of Abnormal Values
Increased
Acute pancreatitis
Acute renal failure
Bacterial pneumonia
Breast cancer
Cholecystitis
Chronic obstructive pulmonary disease
Cirrhosis
Colorectal cancer
Crohn’s disease
Diverticulitis
Hypothyroidism
Leukemia
Lung cancer
Neuroblastoma
Ovarian cancer
Pancreatic cancer
Peptic ulcer disease
Pulmonary emphysema
Radiation therapy
Smoking
Ulcerative colitis
ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Contributing Factors to Abnormal Values
• Smoking may increase CEA levels.
• Drugs that may increase CEA levels: antineoplastic agents, hepatotoxic drugs.
ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Interventions/Implications
Pretest
• Explain to the patient the purpose of the test and the need for a blood sample to be drawn.
• No fasting is required before the test.
Procedure
• A 5-mL blood sample is collected in an EDTA (lavender-top) tube.
• Gloves are worn throughout the procedure.
Posttest
• Apply pressure at venipuncture site. Apply dressing, periodically assessing for continued
bleeding.
• The sample is labeled and transported to the laboratory.
• Report abnormal results to the primary care provider.
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Clinical Alerts
• When cancer metastasizes to other organs, CEA levels rise and may be present
in other body fluids, such as cerebrospinal fluid.
Carcinoembryonic antigen (CEA) is a glycoprotein that is normally produced by the
fetus and secreted by gastrointestinal cells. In adults, it is normally found in trace
amounts. However, CEA tends to increase in the case of malignancies. It is primarily
nonspecific and thus is not used alone in cancer diagnosis. This test has been
found to be effective in the early detection of colorectal cancer, with CEA levels rising
several months before clinical symptoms appear. Smaller tumors found early in
development will have low or normal CEA levels, whereas advanced or metastatic
conditions are likely to have higher CEA levels. Measurement of CEA levels can also
be helpful monitoring the response of the patient to cancer treatment, and for monitoring
the patient for recurrence of cancer.
ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
THE EVIDENCE FOR PRACTICE
• Drawing a CEA level has been recommended before and every 3 months for the first
2 years after resection of colorectal cancer.
• Postoperative return to normal of an elevated preoperative CEA is associated with
complete tumor resection, whereas persistently elevated values indicate the presence
of residual disease.
• Elevated preoperative CEA levels have been found to be an independent predictor
of poor outcome.
ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Normal Values
Nonsmoker: <3 ng/mL (<3 mcg/L SI units)
Smoker: <5 ng/mL (<5 mcg/L SI units)
ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Possible Meanings of Abnormal Values
Increased
Acute pancreatitis
Acute renal failure
Bacterial pneumonia
Breast cancer
Cholecystitis
Chronic obstructive pulmonary disease
Cirrhosis
Colorectal cancer
Crohn’s disease
Diverticulitis
Hypothyroidism
Leukemia
Lung cancer
Neuroblastoma
Ovarian cancer
Pancreatic cancer
Peptic ulcer disease
Pulmonary emphysema
Radiation therapy
Smoking
Ulcerative colitis
ـــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Contributing Factors to Abnormal Values
• Smoking may increase CEA levels.
• Drugs that may increase CEA levels: antineoplastic agents, hepatotoxic drugs.
ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Interventions/Implications
Pretest
• Explain to the patient the purpose of the test and the need for a blood sample to be drawn.
• No fasting is required before the test.
Procedure
• A 5-mL blood sample is collected in an EDTA (lavender-top) tube.
• Gloves are worn throughout the procedure.
Posttest
• Apply pressure at venipuncture site. Apply dressing, periodically assessing for continued
bleeding.
• The sample is labeled and transported to the laboratory.
• Report abnormal results to the primary care provider.
ــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــــ
Clinical Alerts
• When cancer metastasizes to other organs, CEA levels rise and may be present
in other body fluids, such as cerebrospinal fluid.
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