Indicator Explainer
CA19-9 Antigen
CA 19-9 is a fucosylated glycosphingolipid carbohydrate antigen that is soluble and is adsorbed to erythrocytes and to many adenocarcinomas of the digestive tract, especially pancreatic tumors. By structure CA 19-9 is related to the Lewis blood group antigens.
This page explains what the indicator is and how results are interpreted in general terms. Reference ranges depend on the laboratory, the method, and your own situation — no single “normal value” applies to everyone. This page is health information, not a diagnosis. For symptoms, treatment, or urgent concerns, contact a healthcare professional.
When it is tested
Source: National Cancer Institute, NCI Thesaurus 26.09d, C327. NCI definition, reproduced without modification under CC BY 4.0. Source identity and definition checked automatically on 2026-10-18. No individual clinical interpretation or human reviewer is asserted.
Reading results
Reference intervals and interpretation depend on the laboratory, specimen, method and clinical context. This source definition is educational information; it does not establish a diagnosis, product approval or suitability for an individual.