Carcinoembryonic Antigen (CEA) appears in serum or fluid of patients with certain kinds of cancer including, but not limited to, colorectal, gastric, pancreatic, lung, and breast carcinomas.  CEA will also appear elevated in the bloodstream of those diagnosed with ulcerative colitis, pancreatitis, liver cirrhosis, COPD, Crohn’s Disease, and in smokers.

CEA assays are not a reliable diagnosis of cancer, and many types of cancer do not cause elevated levels of CEA.  Test kits are typically used to monitor patients that have already received a diagnosis and have been found to have elevated levels of CEA in the blood.  The test verifies treatment is working if CEA levels are elevated before treatment and lowered after six weeks of treatment.  This assay is also useful in identifying a tumor recurrence after surgical removal of a tumor.