What is this test?
CA 125 is a protein that can rise in conditions affecting the ovaries and other tissues in the abdomen and pelvis. It is most often used for monitoring.
Why might it be ordered?
- To monitor treatment response or recurrence in established ovarian cancer.
- As part of a pelvic assessment along with imaging and other data.
What sample is needed?
A healthcare professional collects a venous blood sample. Depending on the method, the laboratory uses serum or plasma.
How should you prepare?
Tell the laboratory about all medicines, hormone treatments, vitamins and supplements you take. Do not stop or change treatment unless your clinician tells you to. Follow any instructions about fasting and the time of collection.
How should you understand the result?
An increase can also be observed during menstruation, endometriosis, pregnancy, inflammation or benign diseases of the liver and pelvis. A trend across consecutive measurements made with a comparable method is often more informative than a single value.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.