CA-125 Test: What It Screens For and Who Should Get It

Written by Kristy Beard, MSN, APRN, FNP-C — Board-Certified Family Nurse Practitioner and Founder of Elevate Health and Wellness, serving patients across the Gulf Coast in Gautier, MS and Foley, AL.

What Is CA-125?

CA-125 (cancer antigen 125) is a protein found on the surface of certain cells, including ovarian cells. It is measured in blood and has been used for decades as a marker associated with ovarian cancer — particularly epithelial ovarian cancer, the most common type. However, CA-125 is frequently mischaracterized as a definitive ovarian cancer screening test, and understanding its actual clinical utility and limitations is essential for interpreting results accurately.

What CA-125 Can and Cannot Do

CA-125 is most useful as a monitoring tool for women who have already been diagnosed with ovarian cancer — tracking treatment response and detecting recurrence. As a population-wide screening test for ovarian cancer in asymptomatic women, CA-125 has significant limitations: it is not sufficiently sensitive or specific to serve as a standalone screening tool. According to the American Cancer Society and the US Preventive Services Task Force, routine CA-125 screening in average-risk women is not currently recommended because the false positive rate leads to unnecessary procedures and anxiety, and the test does not reliably detect early-stage disease.

When CA-125 IS Clinically Useful

Despite its limitations as a population screening tool, CA-125 has meaningful clinical value in specific contexts. Women with a strong family history of ovarian or breast cancer (BRCA1 or BRCA2 variants) may benefit from CA-125 monitoring as part of a comprehensive surveillance program in consultation with a gynecologic oncologist. Women with known or suspected endometriosis can use CA-125 as a supportive marker, as endometriosis frequently produces elevated CA-125 levels. Women with pelvic masses identified on ultrasound benefit from CA-125 as a component of the diagnostic evaluation. Women with symptoms potentially consistent with ovarian pathology — including persistent bloating, pelvic pain, early satiety, and urinary urgency — warrant evaluation that may include CA-125.

How Elevate Uses CA-125

At Elevate Health and Wellness, Kristy Beard, MSN, APRN, FNP-C does not routinely order CA-125 for all female patients. She orders it selectively for patients with risk factors, symptoms, or ultrasound findings that warrant further evaluation — and always interprets the result in the context of the complete clinical picture, including ultrasound findings, symptoms, and other relevant lab markers. An elevated CA-125 alone is never a diagnosis — it is a signal that warrants further investigation.

Questions about women's health screening? Visit our Women's Health and Lab pages to learn about our comprehensive approach.

Sources: American Cancer Society. CA-125 and Ovarian Cancer. cancer.org. | US Preventive Services Task Force. Ovarian Cancer Screening. uspreventiveservicestaskforce.org.

This article is written by Kristy Beard, MSN, APRN, FNP-C, board-certified Family Nurse Practitioner and founder of Elevate Health and Wellness. Information provided is for educational purposes only and does not constitute medical advice. Please consult a licensed healthcare provider for personalized care.