Cancer antigen CA 19-9 (CA19-9)
Avaible outside the USA
The carbohydrate antigen 19-9 (CA 19-9) is a mucin-type glycoprotein found in the blood, repetitively bearing a carbohydrate epitope, a Lewis sialylated pentasaccharide, which is specifically recognized by the anti-CA 19-9 monoclonal antibody*. It is synthesized by normal human pancreas cells and by the bile ducts, and also by the gastric, colic, endometric and salivary epithelia.
Low levels of the CA 19-9 antigen are found in normal subjects. These levels are temporarily raised in cases of benign inflammatory diseases of bilio-digestive origin.
In neoplasic pathology, CA 19-9 level is useful not only when following up digestive tract tumors (pancreatic, gastric and colo-rectal adenocarcinomas) but also for bile duct cancers, ovarian mucinous cystadenocarcinomas and uterine adenocarcinomas.
This assay should under no circumstances be considered to be a cancer screening test. A low CA 19-9 level does not exclude the possible presence of a malignant tumor, just as a high level is not systematically indicative of the existence of such a tumor.