CA125 is a tumor marker. If CA125 is elevated, the chance of considering ovarian cancer is relatively higher if it is greater than 100 U/ml or more. However, CA125 is not specific and an elevated value does not necessarily mean ovarian cancer. For example, endometriosis, pelvic inflammatory disease, pelvic abscess, ovarian cyst, liver cirrhosis or endometrial cancer, cervical cancer, breast cancer, etc. may cause CA125 to be elevated. The presence of elevated CA125 also requires a pelvic CT or MRI at the hospital for further examination and evaluation. If the test results show the presence of masses in the ovaries, combined with elevated CA125, the chances of considering ovarian cancer are relatively high. However, the diagnosis cannot be confirmed at this time and requires surgery to remove the mass from the ovary for pathological examination to confirm the diagnosis.