The Cancer Ovarian (CA125) blood test is a diagnostic tool used to detect the presence of ovarian cancer in women. This test measures the levels of CA125, a protein that is often elevated in women with ovarian cancer. The test is non-invasive and requires only a small blood sample. Early detection of ovarian cancer through the CA125 blood test can significantly improve a patient's chances of successful treatment and survival. Regular screening for ovarian cancer with the CA125 test is recommended for women who are at higher risk, such as those with a family history of the disease.