Carcinoembryonic Antigen (CEA) Test
Reviewed
CEA (carcinoembryonic antigen) is a protein tumor marker. Healthy adults normally have little or no CEA. High levels can occur in certain cancers (e.g., colorectal, prostate, ovarian, lung, thyroid, liver, pancreatic, breast) and in some non-cancer conditions. This test is used to help assess cancer prognosis, monitor treatment, and check for recurrence, but it is not used for screening or diagnosis.
Preparation and collection
Usually no preparation is needed. If you smoke, you may need to stop for a while before the test because smoking increases CEA levels.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- CEA tests are not used to screen for or diagnose cancer because some cancers that cause high CEA do not always raise levels, and many non-cancer conditions can also increase CEA.
- Different labs may use different methods, which can affect results; it is best to have tests done the same way and usually in the same lab for comparison over time.
- Smoking can increase CEA levels and may affect test interpretation.
What to do next
Discuss your CEA results with your healthcare provider, who will consider them along with other tests and exams to guide your care. If you have questions about how your tests are done, ask your provider.
Evidence source
U.S. National Library of Medicine: Carcinoembryonic Antigen (CEA) Test