Normal CA-125 levels are less than 35 units per milliliter, according to Mayo Clinic and WebMD. The test measures the amount of protein in the blood, and is executed by drawing blood through a vein in the arm or hand, explains Mayo Clinic.
Higher than normal levels may indicate ovarian, endometrial, peritoneal or fallopian tube cancer, states Mayo Clinic. A number of non-cancerous conditions may also cause higher levels, including endometriosis, liver disease, menstruation and pregnancy, pelvic inflammatory disease and uterine fibroids, according to WebMD. Results may also be affected by medicines used to treat cancer, recent radioactive scans and abdominal surgery, explains WebMD.