A CA 125 test measures the amount of the protein CA 125 (cancer antigen 125) in your blood.
A CA 125 test may be used to monitor certain cancers during and after treatment. In some cases, a CA 125 test may be used to look for early signs of ovarian cancer in people with a very high risk of the disease.
The reference range of CA 125 is 0-35 units/mL (0-35 kU/L).
