A blood test for a marker molecule called CA-125 is useful in differential diagnosis and in follow up of the disease, but it by itself has not been shown to be an effective method to screen for early-stage ovarian cancer due to its unacceptable low sensitivity and specificity. CA-125 levels in premenopausal people over 200 U/mL may indicate ovarian cancer, as may any elevation in CA-125 above 35 U/mL in post-menopausal people. CA-125 levels are not accurate in early stage ovarian cancer, as fully half of stage I ovarian cancer patients have a normal CA-125 level. CA-125 may also be elevated in benign (non-cancerous) conditions, including endometriosis, pregnancy, uterine fibroids, menstruation, ovarian cysts, systemic lupus erythematosus, liver disease, inflammatory bowel disease, pelvic inflammatory disease, and leiomyoma. HE4 is another candidate for ovarian cancer testing, though it has not been extensively tested. Other tumor markers for ovarian cancer include CA19-9, CA72-4, CA15-3, immunosuppressive acidic protein, haptoglobin-alpha, OVX1, mesothelin, lysophosphatidic acid, osteopontin, and fibroblast growth factor 23.