Cancer Antigen 19-9 (CA 19-9) Antigen

Sourced from human liver metastases and purified by gel filtration and ion-exchange chromatography, this native CA 19-9 (Cancer Antigen 19-9, also called Sialyl Lewis a / Sialylated Lewis (a) Antigen) antigen is supplied as a 25 kU liquid preparation in 10 mM phosphate buffered saline at approximately pH 7.2 with 0.05% sodium azide as preservative. The Antibodies.com antigen is highly purified (>90% by SDS-PAGE) and is biologically active, typically giving ≥500 kU/mL when calibrated against the Roche Elecsys EIA reference — making it well suited as an immunogen, assay calibrator/control, or standard for ELISA, chemiluminescent immunoassay (CLIA), and Western blot workflows used in pancreatic and gastrointestinal cancer marker research. The material is tested negative at the donor level for HBsAg, anti-HCV and anti-HIV-1/2 by FDA-approved methods, ships on dry ice from St. Louis, MO, and should be stored at -20 °C protected from repeated freeze-thaw cycles to preserve sialyl-Lewis a epitope integrity over its 3-year shelf life.