Pancreatic Tumor Marker (CA 19-9) - Cancer Antigen 19-9 (CA 19-9) Test

The cancer antigen 19-9 (CA 19-9) serum test measures the level of a Lewis antigen-associated glycoprotein known as MUC1. This protein is produced by cells in the pancreatic and bile ducts. Its levels are significantly elevated in pancreatic (adenocarcinoma) cancer, cholangiocarcinoma, and some other gastrointestinal cancers. It can also be elevated in benign biliary obstruction and inflammatory conditions, limiting its usefulness in initial diagnosis.