Cancer Antigen (CA) 125 Serum Test
Cancer antigen 125 (CA-125) is a protein found in ovarian cancer cells. A CA-125 blood test measures the amount of cancer antigen 125 in the bloodstream. The protein is produced by the cells and can be found in the blood.
During and after treatment, a blood test CA-125 can be used to monitor ovarian cancer. In some cases, early signs of ovarian cancer can be checked in women at high risk for the disease. A CA-125 blood test, however, is not sufficiently accurate to detect ovarian cancer in all women because many different conditions can cause abnormal CA-125 levels.
These conditions include:
- pelvic inflammatory disease
- normal menstruation
- endometrial and fallopian tube cancers
- noncancerous growths in the uterus, such as uterine fibroids
- cancer of the pancreas
The progression of ovarian cancer is often monitored by a CA-125 blood test. Baseline CA-125 levels are measured prior to ovarian cancer treatment. A decline in CA-125 levels during and after treatment usually indicates successful treatment. Increases in CA-125 levels after treatment may mean the disease recurrence.
A CA-125 blood test is used for men and women but is most often ordered for women for ovarian cancer-related testing.
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