{"id":"ca-125","name":"CA-125 (Cancer Antigen 125)","shortName":"CA-125","aliases":["CA 125","Cancer Antigen 125","CA125 II","CA 125, Serum","OC125","CA125","Carbohydrate antigen 125","CA-125, Second Generation Assay","Cancer Antigen (CA) 125","Cancer Ag 125 (CA 125), S","CA 125 II","CA-125 II","Ovarian Antigen","OV Monitor","CA-125 Tumor Marker"],"abbreviations":["CA-125","CA 125","CA125"],"loinc":[{"code":"10334-1","primary":true},{"code":"83082-8","primary":false}],"specimen":"serum","units":[{"ucum":"U/mL","display":"U/mL"},{"ucum":"kU/L","display":"kU/L"}],"referenceRanges":[{"population":"Women","low":0,"high":35,"unit":"U/mL","unitDisplay":"U/mL","note":"35 U/mL is the traditional cutoff, printed by Quest and used by the VITROS assay (FDA summary: values above it occur in 1 to 2% of healthy people). Other labs differ: Labcorp prints 0.0 to 38.1 U/mL and Mayo Clinic Laboratories prints under 46 U/mL for women. A 2020 review says about 5% of healthy women are above 35. Labcorp says no range is established for men, and Mayo says the test is not applicable to men. Levels run higher in women who still have periods. Use the range printed on the lab report.","sources":[{"title":"CA 125 (test code 29256)","url":"https://testdirectory.questdiagnostics.com/test/test-detail/29256/ca-125?cc=MASTER","publisher":"Quest Diagnostics"},{"title":"VITROS CA 125 II Reagent Pack: FDA 510(k) summary K221355","url":"https://www.accessdata.fda.gov/cdrh_docs/pdf22/K221355.pdf","publisher":"Ortho Clinical Diagnostics (FDA 510(k) database)","year":2022},{"title":"Cancer Antigen (CA) 125 (test 002303)","url":"https://www.labcorp.com/tests/002303/cancer-antigen-ca-125","publisher":"Labcorp"},{"title":"CA25 - Overview: Cancer Antigen 125 (CA 125), Serum","url":"https://www.mayocliniclabs.com/test-catalog/overview/9289","publisher":"Mayo Clinic Laboratories"}]}],"review":{"status":"ai-verified","label":"AI-verified against cited sources. Awaiting expert review","lastReviewed":"2026-10-03"},"summary":"A protein made by tissue lining the pelvis and belly. Doctors mainly use it to follow ovarian cancer, and many harmless conditions raise it too.","url":"https://bloodtesttracker.com/markers/ca-125","notice":"Information, not medical advice. Ranges differ between labs, so the range on your own report is the one your result is judged against."}