The CEA test is done before colon cancer surgery to determine how widespread the cancer is, and afterwards to determine how effective the surgery was, according to WebMD. CEA stands for carcinoembryonic antigen. It is a protein that is found in developing fetuses and is typically not present in healthy adults.
CEA levels are sometimes measured during certain treatments, such as chemotherapy, to monitor the effect that the treatment is having. CEA levels are measured in the blood, so the procedure for obtaining a sample is a simple blood draw, with results of the test usually available within three days. High levels of CEA in the blood can be indicative of the presence of colon, lung, pancreas, breast or ovarian cancer. High levels can also indicate that a current treatment is not working, that cancer has returned after treatment, or that a previously treated cancer had metastasized and spread to other parts of the body, states WebMD. Sometimes high levels of CEA can indicate that a noncancerous disease is present, such as diverticulitis, hepatitis or peptic ulcer disease.
The CEA test is a reliable test for the recurrence of colon cancer only when the original cancer produced the CEA protein, according to WebMD.