Specimen Requirements


Cancer Antigen (CA) 125

Specimen Requirement

Collect SST or red top, send 1 mL serum. After 30 minutes of clotting, promptly centrifuge and send. If using a red top, transfer serum to a screw top plastic tube, indicate sample type on tube and send.


Electrochemiluminescence immunoassay (ECLIA)


Room temp: 14 days, Refrigerated: 14 days, Frozen: 14 days

Reference Range

By report*


1-2 days

Clinical Use

Used to monitor the course of ovarian cancer, patient response to treatment, and disease recurrence. Serum CA 125 concentrations are elevated in about 80% of women with carcinoma of the ovary, 26% of women with benign ovarian tumors and 66% of women with non-neoplastic conditions, but in only 3% of normal healthy women. CA 125 should not be used alone to diagnose or screen for cancer, but it is useful for monitoring patients with an established diagnosis of a gynecological malignancy that is associated with elevated CA 125 at diagnosis.

The Elecsys CA 125 II assay is labeled “For in vitro diagnostic use” in the manufacturer’s package insert.

Test Code