Carcinoembryonic Antigen (CEA)
Note: this site is for informational purposes only. To view test results or book a test, use the NHS app in England or contact your GP.
The carcinoembryonic antigen (CEA) test measures the level of carcinoembryonic antigen in a blood sample, a protein that can be produced by some cancer cells. It is used mainly to monitor treatment and detect recurrence in cancers such as colorectal cancer, and sometimes other cancers including pancreatic, gastric, and lung cancers.
Why get tested?
In the presence of certain cancers, CEA may be used to monitor the effect of treatment and recurrence of disease
When to get tested?
Before starting cancer treatment as well as at intervals during and after therapy
Sample required?
A blood sample taken from a vein in the arm
Test preparation needed?
No test preparation is needed
Common questions
CEA is most useful to monitor treatment of cancer patients. It is used for patients who have had surgery, to measure response to therapy and to monitor whether the disease has recurred. In 2011, NICE (National Institute for Health and Care Excellence) published guidelines for the diagnosis and management of bowel cancer (CG131) that are currently referred to by the British Society of Gastroenterology. Their recommendations are that bowel surgery is followed up with regular CEA blood testing (at least every 6 months in the first 3 years). A blood test for CEA in this circumstance is used as a tumour marker, i.e. an indicator of whether the cancer is present or not.
CEA is used as a marker for bowel cancer in particular, but may be measured where other forms of cancer are present. It has been found helpful in monitoring some patients with cancer of the rectum, lung, breast, liver, pancreas, stomach, and ovary. Not all cancers produce CEA, and a level within the given reference range does not guarantee that cancer (even the kinds known to produce CEA) is not present, therefore the CEA test is not used for screening the general population.
A CEA test may be requested when the patient’s symptoms suggest the possibility of cancer. CEA is most useful however, when measured in patients with cancers known to produce the protein before and during or after treatment. It is also used to follow up patients after treatment.
The concentration of CEA in the blood does not accurately reflect tumour size, however on initial testing, patients with smaller and early-stage tumours are likely to have low, if not normal, CEA concentrations, while patients with more advanced tumours, or tumours that have spread throughout the body, are likely to have initially high CEA concentrations. When CEA decreases to “normal” concentrations after therapy, it means that the CEA-producing tumour has been removed. A steadily rising CEA result may be the first sign that the cancer has returned.
CEA is a protein that is found in developing tissues of babies. By the time a baby is born, detectable levels in the blood disappear.
Increased CEA concentrations can indicate some non-cancer-related conditions, such as liver disease, and inflammatory bowel disease. Also, smokers tend to have higher concentrations in the blood than non-smokers.
Treatment may include surgery, chemotherapy, or radiation, or a combination of them.
Not necessarily. Smokers can have a higher “normal” range than non-smokers and not have cancer.