CEA (Carcinoembryonic Antigen)

What is CEA?

CEA (carcinoembryonic antigen) is a glycoprotein produced in large amounts in the digestive tissues of the unborn baby. After birth, its production falls sharply, and it is present at low levels in the blood of healthy adults. Some tumors of organs such as the colon, rectum, stomach, pancreas, lung and breast can once again produce CEA in large amounts.

Because of this property, CEA is used as a tumor marker, but on its own it is not a screening or diagnostic test. Its blood level can also rise in smokers and in some benign diseases. For this reason, the result is interpreted together with the person's smoking habits and other conditions. The test is run with automated methods that detect the amount of CEA in serum using antibodies.

When is a CEA test ordered?

CEA is used most often in people who have been diagnosed with colon or rectal cancer. The value measured before surgery gives the doctor additional information about the state of the disease; regular measurements after surgery help monitor the response to treatment and detect a recurrence early. It is not suitable for colon cancer screening in people without symptoms; methods such as the fecal occult blood test and colonoscopy are used for that purpose.

For colon cancer screening and early diagnosis, it is important to plan the methods your doctor recommends according to your age and risk profile. CEA measurement is not part of this plan as a screening tool.

• Establishing a baseline value before surgery in colon and rectal cancer
• Regular follow-up after surgery
• Monitoring the response to treatments such as chemotherapy
• Contributing to the monitoring of some tumors of the stomach, pancreas, lung or breast
• Monitoring medullary thyroid cancer together with calcitonin

How do you prepare for a CEA test?

There is no fasting requirement for CEA measurement; you can give your blood sample at any time of day. Because smoking can raise CEA levels, be sure to state whether or not you smoke; in follow-up measurements, this information is important for interpreting the result correctly. If you take a high-dose biotin (vitamin B7) supplement, report this as well, as it can affect some measurement methods.

A single tube of blood drawn from a vein in the arm is sufficient for this test. Because methods differ from one another, having follow-up measurements done preferably at the same laboratory allows the values to be compared reliably. During post-operative follow-up, the blood sample can also be taken by our nurse at your home or workplace.

What does a CEA result mean?

A high CEA level in the blood does not on its own lead to a diagnosis of cancer. The value can also rise mildly or moderately with smoking and in conditions such as inflammatory bowel diseases like ulcerative colitis and Crohn's disease, pancreatitis, liver diseases, stomach ulcer, chronic lung diseases and kidney failure. For this reason, an unexpected result is evaluated together with other findings and, if necessary, a repeat measurement.

In people who have had surgery for colon cancer, the value is expected to fall after the operation; a steady rise across consecutive measurements during follow-up may lead the doctor to request further investigations such as imaging. Because some tumors do not produce CEA, a normal result does not always rule out disease. Higher values may be expected in smokers, and the laboratory, age and sex also affect the reference range; the range of the laboratory that performs the test is provided on this page. Only a doctor can determine what your CEA value means for you, together with your symptoms and other tests.