CA-125 (Cancer Antigen 125)
- Sample Type
- Standard
- Fasting
- No
- Unit
- U/mL
The CA-125 test measures the amount of the protein Cancer Antigen 125 in the blood. Within an Ovarian Cancer Panel, it serves as a primary tumor marker. It is most useful for monitoring the effectiveness of treatment and checking for recurrence in patients already diagnosed with epithelial ovarian cancer. It is not generally used as a primary screening tool for asymptomatic individuals because many non-cancerous conditions can cause elevations.
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Check Your Result
Enter your lab result to see where you stand compared to the standard reference range.
Why Context Matters
CA-125 is notoriously non-specific in pre-menopausal women. Levels can be elevated due to menstruation, pregnancy, endometriosis, pelvic inflammatory disease (PID), or even liver disease. A second opinion or follow-up imaging (like Transvaginal Ultrasound) is crucial if levels are mildly elevated without symptoms.
Lab ranges are statistical averages, not biological laws. "Normal" for a 20-year-old male isn't normal for a 60-year-old female.
Clinical References
Source-of-truth databases and clinical guidelines for CA-125 (Cancer Antigen 125):
Official Sources
- Cancer of the ovary, fallopian tube, and peritoneum: 2025 update - PMCpmc.ncbi.nlm.nih.gov
Research & Guidelines
Related Indicators
Medically Reviewed by Dr. Binoy Babu, MBBS
Board Certified Doctor • 10+ Years Clinical Experience
Dr. Babu is a practicing physician dedicated to empowering patients with clear, actionable medical information. He founded 2opi to bridge the gap between complex lab reports and patient understanding, ensuring everyone has access to a reliable second opinion.
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