The carcinoembryonic antigen, or CEA, levels of postoperative colon cancer patients are regularly checked by physicians as changes in the levels may indicate a relapse of the cancer. Relapse of other types of cancers such as cancer of the rectum, lungs, breast, pancreas, stomach and ovaries may also be monitored by checking the CEA levels according to the National Institutes of Health.
The CEA is a type of protein that is produced in the gastrointestinal issue during fetal development. Healthy adults, have low levels of CEA and elevation in blood serum levels from the normal ranges of CEA is one of the indications of tumor growth. The following shows the basic steps taken when testing for CEA levels according to the National Institutes of Health and WebMDwebsites.
A blood sample is drawn from the patient,usually from a vein in the arm. Since smokers tend to have elevated CEA levels, the attending physician may ask the patient to refrain from smoking for a certain span of time before the test is conducted.
The sample is then tested for CEA levels by expert technicians. Results will be available between one to three days. The normal levels of CEA are less than 5 nanograms per milliliter or less than 5 micrograms per liter. Higher levels for newly treated patients may indicate a relapse of the cancer and may signify a presence of certain types of cancers for other patients. Note that some types of cancers do not affect CEA levels.