A serum CA-125 assay does not need to be undertaken in all premenopausal women when an ultrasonographic diagnosis of a simple ovarian cyst has been made. CA-125 is unreliable in differentiating benign from malignant ovarian masses in premenopausal
women because of the increased rate of false positives and reduced specificity.

It is recommended that ovarian cysts in postmenopausal women should be initially assessed by measuring serum cancer antigen 125 (CA125) level and transvaginal ultrasound scan.