Cancer Antigen 125 (CA-125)

The test for cancer antigen 125 (CA-125) is used to:

• Check to see if treatment for cancer is working. If the level of CA-125 is going down, it usually means that the treatment is working.
• Check to see if ovarian cancer has returned.
• Check to see if the ovary is the main site of cancer in a woman. If a doctor has found a cancer that has spread to another part of the body (metastatic cancer), he or she may do a CA-125 test to find out where the cancer started. High levels of CA-125 are a strong sign that the cancer started in the ovary. But other types of cancer can increase CA-125 levels too.

The CA-125 test is not recommended as a screening test for ovarian cancer at this time because it often has Reference false-positive results Opens New Window. But the CA-125 test and an Reference ultrasound Opens New Window scan may be used to test women who have a high chance of developing ovarian cancer. Women have a high risk of getting ovarian cancer if they have a family history of ovarian cancer or certain changes (mutations) in their Reference DNA Opens New Window (BRCA1 or BRCA2).

© 1995-2011, Healthwise, Incorporated. Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Reference Terms of Use. Reference How this information was developed to help you make better health decisions.