Definition of CA-125:

CA-125 is a test used to evaluate ovarian cancer treatment.

How the test is performed:

Blood is typically drawn from a vein, usually from the inside of the elbow or the back of the hand. The site is cleaned with germ-killing medicine (antiseptic). The health care provider wraps an elastic band around the upper arm to apply pressure to the area and make the vein swell with blood.

Next, the health care provider gently inserts a needle into the vein. The blood collects into an airtight vial or tube attached to the needle. The elastic band is removed from your arm. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

How to prepare for the test:

No preparation is necessary.

How the test will feel:

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

Why the test is performed:

CA-125 is a protein that is found more in ovarian cancer cells than in other cells. This protein enters the bloodstream and can be measured by a blood test. There are two CA-125 tests: a first and second generation test. The second generation test is now more widely used and is generally more accurate.

The test is often used to follow women who have already been diagnosed with ovarian cancer. In these cases, the CA-125 is a very good indicator of whether a patient is responding to treatment, and whether a patient remains in remission after treatment. In general, the CA-125 is not a good test to screen healthy women for ovarian cancer.