CA19.9 (Carbohydrate Antigen 19-9)  is present in the fetal epithelium of the stomach, intestine, liver and pancreas. In adults traces can be found in the pancreas, liver, gallbladder and lung. Its primary use is as a marker for cancer of the pancreas. It is also elevated in cancers of the liver, lung, breast, uterus and ovary (mucinous).

CA19.9 may also be elevated in non-malignant liver diseases such as cirrhosis and hepatitis. Other less frequent non-malignant disease elevations include pancreatitis, autoimmune diseases, cystic fibrosis and disorders of the kidney, lung and the GI tract.

CA19.9 is a MEIA AxSYM assay. Samples must be serum.

Reference Range =< 37 kU/L

Interferences: HAMA . Please note that patients with the Lewis negative blood group phenotype may not express CA19.9 antigen.​