Carbohydrate antigen 19-9 (CA 19-9) is a modified Lewis(a) blood group antigen.
Mucin occurs in fetal gastric, intestinal and pancreatic epithelia. Low concentrations can also be found in adult tissue in the liver, lungs, and pancreas. CA 19‑9 assay values can assist in the differential diagnosis and monitoring of patients with pancreatic carcinoma. May be used for differentiating patients with cholangiocarcinoma and primary sclerosing cholangitis (PSC) from those with PSC alone.
As the mucin is excreted exclusively via the liver, even slight cholestasis can lead to clearly elevated CA 19‑9 serum levels in some cases.
Elevated CA 19‑9 values are also found with a number of benign and inflammatory diseases of the gastrointestinal tract and the liver, as well as in cystic fibrosis.
There is an additional £15 phlebotomy fee.
