CA 15-3 (Cancer Antigen 15-3)

SI UNITS (recommended)


* The SI unit is the recommended method of reporting clinical laboratory results

Carbohydrate Antigen 15-3
Units of measurement
U/mL, kU/L

Immunological in vitro assay for quantitative determination of CA 15‑3 in human serum and plasma to aid in the management of breast cancer patients. In conjunction with other clinical and diagnostic procedures, serial testing with this assay is an aid

▪ in the early detection of recurrence in previously treated stage II and III breast cancer patients

▪ for monitoring response to therapy in metastatic breast cancer patients.

The CA 15‑3 values measured are defined by the use of the monoclonal antibodies (MAb) 115D8 and DF3 in a sandwich assay. MAb 115D8 is directed against human milk fat globule membranes, whereas MAb DF3 is directed against the membrane fraction from human metastatic breast cancer. The 115D8 and DF3‑reactive determinants detected by the test are located on a glycoprotein having a molecular weight of > 400 kD. The antigen is termed MAM‑6 and belongs to a subgroup of sialylated glycoproteins designated polymorphic epithelial mucin (PEM). Polymorphic epithelial mucins (PEMs) are normally found in the luminal secretion of glandular cells and do not circulate in the blood. When cells become malignant and their basal membranes permeable, PEMs are detectable in serum using the CA 15‑3 assay.

SI units Conversion Calculator. Convert CA 15-3 (Cancer Antigen 15-3) level to U/mL, kU/L . Clinical laboratory units online conversion from conventional or traditional units to Si units. Table of conversion factors for CA 15-3 (Cancer Antigen 15-3) unit conversion to U/mL, kU/L .