Description

What is a CA-125 test?

A CA-125 test is a blood test that measures the amount of the protein CA-125, also called cancer antigen 125, in your body.

CA-125 is a type of biomarker or a substance in your blood that may be a sign of a condition or disease. A high level of CA-125 can be a sign of ovarian cancer. Your ovaries are a pair of reproductive glands that store and release eggs and produce hormones.

A CA-125 test can have both false positive and false negative findings. CA-125 levels can be normal even if you have cancer (false negative), or they can be elevated when you don’t have cancer (false positive). For this reason, a CA-125 test isn’t an effective screening for ovarian cancer.

Instead, healthcare providers will order a CA-125 blood test as part of an overall approach to monitoring certain types of cancer, especially during and after cancer treatment.

Providers also use this test for the early detection of ovarian cancer in people who are at high risk. This could include factors such as if an immediate family member had ovarian cancer or if you have been found to have a genetic mutation or error that increases your risk of developing ovarian cancer. A CA-125 test isn’t useful for people with no symptoms or risk factors.