CA 125 (CA-125)
CA 125 (also written CA-125) is a cancer marker, a protein normally made by certain cells in the body including those of the uterine tubes, uterus, cervix, and the lining of the chest and abdominal cavities (the peritoneum and pleura). CA 125 stands for cancer antigen 125. CA 125 is measured in a blood sample or fluid from the chest or abdominal cavity. While it is a useful test, it is not 100% accurate. It has both false positives and false negatives and must be correlated with this medical history and physical condition of a patient as well as with other lab tests.