The carcinoembryonic antigen (CEA) test is an essential tool in cancer management. Used primarily to monitor patients who have already been diagnosed, this test helps assess the severity of the disease, the effectiveness of treatments, and the detection of recurrences. Understanding how it works can greatly influence the care journey.
CEA stands for carcinoembryonic antigen. CEA is a protein that is a type of “tumor marker.” Tumor markers are substances that are often produced by cancer cells or by normal cells in response to cancer.
High CEA levels are normal in healthy and unborn babies. After birth, CEA levels become very low or disappear altogether. Thus, healthy adults should have little or no CEA in their bodies.
Cancers that can cause high CEA levels include cancers of:
If you have been diagnosed with cancer that can cause high CEA levels, the CEA test can help your health care provider learn more about your cancer and your chances of recovery. The test is often used along with other tests to see if cancer treatment is working.
CEA tests are not steps used to screen for or diagnose cancer. That's because:
Most CEA tests use a sample of your blood to measure your CEA level. Sometimes the test uses a sample of fluid from your spine, chest, or abdomen (belly), but this is less common.
Other names: CEA assay, CEA blood test, carcinoembryonic antigen test
An CEA test is primarily used in people who have been diagnosed with cancers that often increase CEA levels. It is most commonly used in colorectal cancer. A healthcare professional may request a CEA test at the same time as other tests for:
If you have been diagnosed with a type of cancer that can cause high CEA levels, you may need an CEA test:
The CEA is usually measured using a blood sample. During a CEA blood test, a health 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 in a test tube or vial. You may feel a slight prick when the needle goes in or out. This usually takes less than five minutes.
Sometimes CEA is tested in other body fluids. For these tests, your provider will remove a small sample of liquid using a fine needle.
For a CEA blood test, you usually don't need to prepare. If you smoke, you may need to stop for a while before your test. This is due to the fact that smoking increases CEA levels.
One CEA blood test has very few risks. You may feel a slight pain or bruise where the needle was inserted, but most symptoms go away quickly.
To understand the results of your CEA test, your provider will consider the results of other tests and exams. Ask your provider to explain what your test results mean for your health and treatment.
If you have taken a test before starting cancer treatment, in general:
If you have passed a test to monitor your cancer during or after treatment, your provider will compare your current CEA test results with your past test results. In general:
CEA levels that remain high or increase after treatment Don't does not always mean that the treatment is not working, or that the cancer is growing. So if your CEA levels aren't going down, your supplier will likely order more tests to find out why.
If you have questions about your results, talk to your provider.
Learn more about lab tests, reference ranges, and understanding results.
Laboratories use different methods to measure CEA. The test method may affect your results. It is therefore preferable to do your tests in the same way, and generally in the same laboratory. This allows your provider to compare your results over time. If you have questions about how your tests are done, ask your provider.
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