CA-125 (CA-125) | LabsVault

What is CA-125?

CA-125 is a protein that can be elevated in certain cancers, particularly ovarian cancer. It’s also found in normal tissues including the fallopian tubes, uterus, and peritoneum. While useful for monitoring, it’s not specific to cancer and can be elevated in benign conditions.

Why is it Tested?

Doctors order CA-125 primarily to monitor ovarian cancer treatment response and detect recurrence in women with known disease. It may also be used alongside other tests when investigating pelvic masses or symptoms suggestive of ovarian cancer, though it’s not recommended for routine screening.

Normal Ranges

Reference ranges for women:

Women: <35 U/L

CA-125 levels can fluctuate with menstrual cycle, pregnancy, and various benign conditions. Postmenopausal women typically have lower baseline levels than premenopausal women.

Reference ranges vary by authority. Track yours across multiple standards with automatic unit conversions in LabsVault.

What do Abnormal Results Mean?

Abnormal results are not a diagnosis. Always discuss your results with a qualified healthcare provider before making any medical decisions.

Elevated CA-125

Higher levels may indicate:

Ovarian, fallopian tube, or peritoneal cancer
Endometriosis
Uterine fibroids
Pelvic inflammatory disease
Liver disease or heart failure

Normal CA-125

Normal levels suggest:

Absence of conditions that typically elevate CA-125
Successful cancer treatment response
Early-stage disease (some cancers don’t elevate CA-125)
Need for additional testing if clinical suspicion remains

How to Track Over Time

For cancer monitoring, CA-125 trends are more informative than single values. Rising levels may signal disease progression or recurrence, while declining levels suggest treatment response. Regular tracking helps oncologists adjust treatment plans and detect changes early.

CA-125