What is a CA-125 blood test?
This test measures the amount of a protein called CA-125 (cancer antigen 125) in the blood. CA-125 levels are high in many women with ovarian cancer. The ovaries are a pair of female reproductive glands that store ova (eggs) and make female hormones. Ovarian cancer happens when there is uncontrolled cell growth in a woman's ovary. Ovarian cancer is the fifth most common cause of cancer death in women in the U.S.
Because high CA-125 levels can be a sign of other conditions besides ovarian cancer, this test is not used to screen women at low risk for the disease. A CA-125 blood test is most often done on women already diagnosed with ovarian cancer. It can help find out if cancer treatment is working, or if your cancer has come back after you have finished treatment.
Other names: cancer antigen 125, glycoprotein antigen, ovarian cancer antigen, CA-125 tumor marker
