The CA125 test is a blood test that measures the amount of a protein called CA125 in the blood. This protein is produced by certain cells in the body, including the cells that line the uterus, fallopian tubes, and ovaries. The CA125 test is often used to monitor treatment and recurrence of ovarian cancer, as well as to help diagnose other conditions.
Ovarian cancer is the most common cause of elevated CA125 levels, but other conditions can also cause an increase in CA125, such as endometriosis, uterine fibroids, and pelvic inflammatory disease. In some cases, a CA125 test may be ordered along with other tests, such as an ultrasound, to help diagnose or rule out ovarian cancer.
The CA125 test is usually done by taking a blood sample from a vein in the arm. The blood sample is sent to a laboratory for analysis. Normal levels of CA125 in the blood are generally considered to be less than 35 units per milliliter (U/mL). However, some women with ovarian cancer may have normal CA125 levels, and some women without ovarian cancer may have elevated CA125 levels, so the test is not a definitive diagnostic tool.
If a CA125 test comes back with elevated levels, further testing and evaluation may be needed to determine the cause. This may include additional blood tests, imaging tests, or a biopsy.
It’s important to note that the CA125 test is not a routine screening test for ovarian cancer, and is typically only used for women who have already been diagnosed with ovarian cancer or who are at high risk for the disease. Women who are concerned about their risk of ovarian cancer should talk to their healthcare provider about appropriate screening and diagnostic tests.
