CA 125 test: A screening test for ovarian cancer?

Date Updated: 08/06/2020

Answer Section

The cancer antigen 125 (CA 125) blood test isn't recommended for women with an average risk of ovarian cancer.

While women with ovarian cancer often have an elevated level of CA 125, an elevated CA 125 level doesn't always mean you have ovarian cancer. Some women with ovarian cancer never have an elevated CA 125 level.

Many other conditions also can cause an elevated CA 125 level, including:

Endometriosis
Liver cirrhosis
Normal menstruation
Pelvic inflammatory disease
Uterine fibroids

For these reasons, doctors don't recommend CA 125 testing in women with an average risk of ovarian cancer.

Women with a high risk of ovarian cancer, such as those with mutations in the BRCA1 and BRCA2 genes, which increase the risk of breast and ovarian cancers, may consider periodic CA 125 testing. But even in these high-risk situations, there's some disagreement about the usefulness of the CA 125 test.

A study of 78,216 women ages 55 to 74 randomly selected to receive either an annual CA 125 test and pelvic ultrasound screening or the usual medical care showed that CA 125 testing and ultrasound screening did not reduce ovarian cancer deaths. The study also found that false-positive tests led to additional testing and procedures that sometimes resulted in serious complications.

If you're concerned about your risk of ovarian cancer, ask your doctor about your screening options and ways to reduce your risk.