A CA-125 test is a blood test that quantifies your body's levels of the protein CA-125, also known as cancer antigen 125.

CA-125 is a form of biomarker, or a substance in your blood that could be an indication of a disorder or disease. Ovarian cancer may be indicated by a high CA-125 level. Your ovaries are a pair of reproductive glands that make hormones, store, and release eggs.

This test is also used by doctors to identify ovarian cancer early in high-risk patients. This may include elements like having ovarian cancer in your direct family or being identified as having a genetic mutation or error that raises your risk of getting the disease.

Some individuals may undergo the CA-125 test for the purposes of ovarian cancer diagnosis, therapy, and follow-up. This test is also applied to peritoneal or fallopian tube cancer.

A CA-125 blood test 

Check the effectiveness of ovarian cancer treatment. If your numbers decrease over time, it typically indicates that your cancer treatment is effective.

There will always be a chance the cancer is coming back, so routine monitoring is necessaryIf. Depending on when you ended your treatment, this may be done every few months or once a year.

This test assists doctors in the evaluation of a person who exhibits ovarian cancer symptoms or who is suspect of having the cancer.

If a CA-125 test is requested and the results are positive, doctors will  likely order additional tests to learn more. Transvaginal ultrasound is one of these. Another option is to retake the CA-125 test later to check whether the results have changed.