Definition of CA 19-9

CA 19-9: A tumor marker initially found in colorectal cancer patients, but subsequently also identified in patients with pancreatic, stomach, and bile duct cancer. In those who have pancreatic cancer, higher levels of CA 19-9 tend to be associated with more advanced disease. Noncancerous conditions that may elevate CA 19-9 levels include gallstones, pancreatitis, cirrhosis of the liver, and cholecystitis.