CA 125 assay is used as an aid in monitoring the response to therapy for patients with epithelial ovarian cancer. Studies have shown about 50% of individuals with ovarian cancer have elevated CA 125 values. Serial testing for patient CA 125 assay values should be used in conjunction with other clinical methods for monitoring ovarian cancer. CA 125 values obtained by other methods cannot be used interchangeably due to differences in assay methods and reagent specificity.
Elevations of CA 125 have been reported in healthy individuals, and in individuals with non-malignant diseases. The most common benign conditions associated with CA-125 increase includes menstruation, pregnancy, benign pelvic tumors, pelvic inflammatory diseases, ovarian hyperstimulation syndrome, peritonitis, and many diseases leading to pleural effusion or ascites. Therefore, because of the high frequency of false-positive results associated with many benign conditions, CA-125 is of little value as a screening test for ovarian carcinoma. Therefore, although not recommended, if used as a screening test, care must be taken in the interpretation of the results.
Source:
1. Abbott Alinity CA125 II Package insert: B8P490, Jan. 2017.