The CA 125 test calculates the blood's concentration of the protein CA 125 (Cancer antigen 125). This test can be used to keep an eye on some malignancies both during and after treatment and occasionally to screen for early indications of ovarian cancer in women who have a very high risk of developing the disease. In general, the CA 125 test is not reliable enough to be used for ovarian cancer screening because numerous diseases might cause this protein to be elevated. Many non-cancerous conditions, such as menstruation and uterine fibroids can result in a rise in CA 125. Additionally, some malignancies, such as ovarian, endometrial, peritoneal and fallopian tube tumours might result in an elevated level of CA 125.