Cancer Antigen 19-9

CA 19-9 is a substance found in the blood that can be higher in people with certain types of cancer, such as those affecting the pancreas, liver, stomach, and colon. Doctors check the levels of CA 19-9 to see how a patient’s cancer treatment is going or to see if the cancer might be coming back after treatment. However, this test isn’t used to check if someone has cancer for the first time because it’s not specific enough just for screening.