Carcinoembryonic Antigen Test The carcinoembryonic antigen (CEA)
test is a laboratory blood study. CEA is a substance which is
normally found only during fetal development, but may reappear
in adults who develop certain types of cancer. The CEA test is
ordered for patients with known cancers. The CEA test is most
commonly ordered when a patient has a cancer of the
gastrointestinal system. These include cancer of the colon,
rectum, stomach (gastric cancer), esophagus, liver, or pancreas.
It is also used with cancers of the breast, lung, or prostate.
The CEA level in the blood is one of the factors that doctors
consider when determining the prognosis, or most likely outcome
of a cancer. In general, a higher CEA level predicts a more
severe disease, one that is less likely to be curable. But it
does not give clear-cut information. The results of a CEA test
are usually considered along with other laboratory and/or
imaging studies to follow the course of the disease. Once
treatment for the cancer has begun, CEA te