Diagnosis: Carcinoembryonic Antigen

The carcinoembryonic antigen (CEA) test is a blood test that measures the level of CEA protein in the blood.  The CEA protein is present in the developing embryo, but disappears from the blood by birth and normally remains at undetectable levels throughout adulthood.  When CEA does appear in the blood of an adult, it may indicate presence of a cancer, including pancreatic cancer.  However, the test is not used to diagnose pancreatic cancer because the CEA protein is not produced by all pancreatic tumors.  Other tumors, such as colon cancer, may also cause a rise in CEA.  In addition, other factors, such as smoking, can increase CEA concentration in the blood even when no cancer is present.  Similar to CA 19-9, CEA cannot be used as a diagnostic or screening test for pancreatic cancer.  Measuring blood CEA levels is most effective to monitor if an existing pancreatic tumor is responding to treatment.  If a pancreatic tumor produces the CEA protein and surgery is performed to remove the tumor, CEA levels in the blood should return to normal.