What is being tested?Cancer antigen 19-9 (CA 19-9) is a
protein that exists on the surface of certain cells. CA 19-9 does not cause cancer; rather, it is a protein that is produced by the tumour cells, making it useful as a
tumour marker to follow the course of the cancer.
CA 19-9 is elevated in most patients with advanced
pancreatic cancer, but it may also be elevated in other cancers and diseases such as
bowel cancer, lung cancer, gall bladder cancer, gall stones,
pancreatitis,
cystic fibrosis, and
liver disease. Very small amounts of CA 19-9 may also be found in healthy patients.
