What is CEA test

CEA test is short for carcinoembryonic antigen test that measures the amount of CEA in the blood to help evaluate individuals diagnosed with cancer. CEA (carcinoembryonic antigen) is a protein that is present in certain tissues of a developing baby (fetus). Carcinoembryonic antigen (CEA) is a glycoprotein normally found in embryonic entodermal epithelium. By the time a baby is born, CEA (carcinoembryonic antigen) drops to a very low level. In adults, CEA is normally present at very low levels in the blood but may be elevated with certain types of cancer. However, carcinoembryonic antigen levels are not useful in screening the general population for undetected cancers.

CEA is a tumor marker. Originally, it was thought that CEA was a specific marker for colon cancer, but further study has shown that an increase in CEA may be seen in a wide variety of other cancers. CEA can also be increased in some non-cancer-related conditions, such as inflammation, cirrhosis, peptic ulcer, ulcerative colitis, rectal polyps, emphysema, and benign breast disease, and in smokers. For this reason, CEA (carcinoembryonic antigen) is not useful as a general cancer screening tool, but it does have a role in evaluating response to cancer treatment. When an individual has been diagnosed with cancer, an initial baseline test for CEA may be performed. If this level is elevated, then subsequent serial testing of CEA may be performed to monitor the cancer as the individual undergoes treatment. CEA may be useful in assessing the effectiveness of chemotherapy or radiation treatment.

CEA test may be used for monitoring colorectal cancer and selected other cancers such as medullary thyroid carcinoma. A CEA test may be ordered when a person has been diagnosed with colon cancer or other specific types of cancer. It will be measured before therapy is initiated and then on a regular basis to evaluate the success of treatment and to detect recurrence.

Sometimes a CEA test may be performed when cancer is suspected but not yet diagnosed. This is not a common use for the test because CEA can be elevated with many conditions, but it may provide a healthcare practitioner with additional information.

A CEA test may sometimes be performed on a fluid other than blood when a healthcare practitioner suspects that a cancer has metastasized (e.g., spread to the pleural or peritoneal cavity).

CEA blood test key facts

• Carcinoembryonic antigen levels are not useful in screening the general population for undetected cancers.
• The concentration of carcinoembryonic antigen (CEA) in serum should not be used to screen asymptomatic individuals for neoplastic disease, and the diagnostic efficacy of CEA measurements in high-risk groups has not been established.
• Single values of CEA are less informative than changes assessed over time.
• CEA values are method-dependent; therefore, the same method should be used to serially monitor patients.
• Do not interpret serum CEA levels as absolute evidence of the presence or the absence of malignant disease. Use serum CEA in conjunction with information from the clinical evaluation of the patient and other diagnostic procedures.
• Some patients who have been exposed to animal antigens, either in the environment or as part of treatment or imaging procedures, may have circulating antianimal antibodies present. These antibodies may interfere with the assay reagents to produce unreliable results.

Normal carcinoembryonic antigen level

• Nonsmokers: CEA level < or =3.0 ng/mL
• Most healthy subjects (97%) have values of 0 to 2.5 ng/mL (0 to 2.5 µg/L).
• Some smokers may have elevated CEA, usually <5.0 ng/mL (0 to 5 µg/L).
• Serum markers are not specific for malignancy, and values may vary by method.

Laboratories may use different methods to test for CEA, so results can vary from lab to lab. If you are having a series of CEA tests done, it is advised that you have the tests done by the same method, typically by the same laboratory, so that the results can be compared and interpreted correctly. You may wish to discuss this issue with your healthcare provider.

Individuals who smoke cigarettes tend to have higher CEA levels than non-smokers.

Increased CEA levels can indicate some non-cancer-related conditions, such as inflammation, cirrhosis, peptic ulcer, ulcerative colitis, rectal polyps, emphysema, and benign breast disease.

Why do I need a CEA test?

You may need this test if you’ve been diagnosed with cancer. Your health care provider may test you before you start treatment, and then regularly throughout the course of your therapy. This can help your provider see how well your treatment is working. You may also get a CEA test after you’ve completed treatment. The test can help show whether the cancer has come back.

Will every person with cancer have a CEA test performed?

No. CEA has a role to play in certain tumors, particularly colon cancer. However, a number of other tumor markers have been developed to monitor cancers from different areas of the body. As an example, breast cancer is usually monitored with a CA 15-3 test or a CA 27.29 test. For some cancers, testing for tumor markers is not done at all.

What happens during a CEA test?

CEA is usually measured in the blood. During a CEA blood test, a health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.

Sometimes, CEA is tested in the spinal fluid or from fluid in the abdominal wall. For these tests, your provider will remove a small sample of fluid using a thin needle and/or syringe. The following fluids may be tested:

• Cerebrospinal fluid (CSF), a clear, colorless liquid found in the spinal cord
• Peritoneal fluid, a fluid that lines your abdominal wall
• Pleural fluid, a liquid inside your chest cavity that covers the outside of each lung

Will I need to do anything to prepare for the test?

You don’t need any special preparations for a CEA blood test or a pleural fluid test.

You may be asked to empty your bladder and bowels before a CSF or peritoneal fluid test.

How is CEA test used?

The carcinoembryonic antigen (CEA) test may be used:

• To monitor the treatment of people diagnosed with colon cancer. It may also be used as a marker for medullary thyroid cancer and cancers of the rectum, lung, breast, liver, pancreas, stomach, and ovaries. An initial CEA test is typically ordered prior to treatment as a “baseline” value. If the level is elevated, then the test can be used to monitor a person’s response to therapy and to determine whether the cancer has progressed or recurred.
  • If you were tested before you started treatment for cancer, your results may show:
    • A low level of CEA. This may mean your tumor is small and the cancer has not spread to other parts of your body.
    • A high level of CEA. This may mean you have a larger tumor and/or your cancer may have spread.
  • If you are being treated for cancer, you may be tested several times throughout treatment. These results may show:
    • Your levels of CEA started high and remained high. This may mean your cancer is not responding to treatment.
    • Your levels of CEA started high but then decreased. This may mean your treatment is working.
    • Your CEA levels decreased, but then later increased. This may mean your cancer has come back after you’ve been treated.
• To stage cancer — cancer staging involves evaluating the size of the tumor as well as how far it has spread.
• Testing CEA in a body fluid sample may help to determine if cancer has spread to a body cavity such as the chest or abdomen (pleural or peritoneal cavity). If you had a test on a body fluid (CSF, peritoneal, or pleural), a high level of CEA may mean the cancer has spread to that area.

A CEA test may be used in combination with other tumor markers in the evaluation of cancer.

Not all cancers produce CEA, and a positive CEA test is not always due to cancer. Therefore, CEA is not recommended for screening the general population.

What does the CEA test result mean?

If you have questions about your results, talk to your health care provider. Grossly elevated carcinoembryonic antigen (CEA) concentrations (>20 ng/mL) in a patient with compatible symptoms are strongly suggestive of the presence of cancer and also suggest metastasis.

For treatment, recurrence monitoring:

When CEA levels are initially elevated and then decrease to normal after therapy, it means the cancer has been successfully treated. A steadily rising CEA level is often the first sign of tumor recurrence.

After removal of a colorectal tumor, the serum CEA concentration should return to normal by 6 weeks, unless there is residual tumor.

Increases in test values over time in a patient with a history of cancer suggest tumor recurrence.

For staging:

On initial testing, people with smaller and early-stage tumors are likely to have a normal or only slightly elevated CEA value. People with larger tumors, later-stage cancer, or tumors that have spread throughout the body are more likely to have a high CEA value.

Testing for metastasis:

If CEA is present in a body fluid other than blood, then the person’s cancer is likely to have spread into that area of the body. For example, if CEA is detected in cerebrospinal fluid, this may indicate that cancer has spread to the central nervous system.

Since not all cancers produce CEA, it is possible to have cancer but also have a normal CEA. If a cancer does not produce CEA, then the test will not be useful as a monitoring tool.

Elevated CEA level

A high CEA level in a person recently treated for certain cancers may mean the cancer has returned. A higher than normal level may be due to the following cancers:

• Breast cancer
• Cancers of the reproductive and urinary tracts
• Colon cancer
• Lung cancer
• Pancreatic cancer
• Thyroid cancer

Higher than normal CEA level alone cannot diagnose a new cancer. Further testing is needed.

An increased CEA level may also be due to:

• Liver and gallbladder problems, such as scarring of the liver (cirrhosis), or gallbladder inflammation (cholecystitis)
• Heavy smoking
• Inflammatory bowel diseases (such as ulcerative colitis or diverticulitis)
• Lung infection
• Inflammation of the pancreas (pancreatitis)
• Stomach ulcer