Tumor Marker Blood Test (CEA)Next »
CEA (carcinoembryonic antigen) is a protein that is released into the blood by some cancer cells in some (but not all) people. Sometimes other cells may release it, and in some patients CEA is never present at levels that can be detected.
The CEA blood test measures the amount of carcinoembryonic antigen in the blood stream. CEA is not usually in the blood of healthy adults. CEA testing is a reliable test for recurrent colon cancer if the original cancer produced this protein before treatment.
Not all people with colorectal cancer have elevated CEA levels. On the other hand, sometimes other cells may release CEA. Still, CEA levels are genearlly checked prior to surgery or other treatment to monitor the body's response.
CEA is usually drawn monthly during and shortly after treatment has ended.
- There is nothing to do to prepare for the test.
- Results from the test are usually available in 1 - 3 days. (For tips about how to cope during the wait, click here.)
- The results from the laboratory will show normal range as well as yours, so you can see how your result compares to the norm. High values mean that cancer is present, how cancer is responding to treatment and whether it has returned.
If you are one of the people who has an elevated CEA level prior to your surgery or other treatment, it should return to normal within a few weeks after surgery or other treatment if all the cancer was removed. If it does not return to normal levels, your doctors need to investigate to find the source of the elevated CEA level there could be micrometastatic disease, disease that does not show up on scans.
The definition of a "normal CEA level" varies from lab to lab. You will need to check with your doctor to learn what the normal level is in the laboratory he/she uses. In most labs the normal level is 0-3 mcg/L for people who do not smoke and 0-5 mcg/L for smokers. In a few places a normal level of 0-5 mcg/L is used for all patients.
If a patient's CEA marker level returns to normal after surgery and/or treatment, then begins to increase, a doctor will want to investigate and find out why the CEA level is increasing.
- If your CEA begins to rise, keep in mind that CEA is an imperfect measure of a protein that does not necessarily mean that cancer is present. Increased CEA levels may mean that you have another medical problem because many illnesses, and even the cancer treatment itself can cause cells to produce an increased level of CEA. It can also mean that the cancer has recurred.
- Usually at least two consecutive increases in CEA will need to be reported before further investigation into a recurrence of cancer is initiated.
- Heavy smoking affects the results of this test. For ideas about quitting smoking, click here.
- To learn how a CEA test is given, click here.