What it measures
CA125 is a protein made by cells lining the ovaries, womb, tummy and chest. The test measures how much is in the blood. Levels can be raised by ovarian cancer, but also by many other conditions.
Why people test it
- Measured when symptoms such as persistent bloating, feeling full quickly or pelvic pain are being looked into.
- Requested with an ultrasound scan when a GP thinks ovarian cancer is possible.
- Used to follow ovarian cancer over time, during and after hospital care.
Typical range
Ranges and cut-offs vary by lab and method, and levels can rise with periods, pregnancy, endometriosis and other conditions that are not cancer. Your report shows the lab's own cut-off.
Finger-prick or vein?
A finger-prick sample is often enough, as the test needs only a small amount of serum. A vein sample is taken where a lab or a larger panel needs more blood.
There is no NHS screening programme for ovarian cancer. CA125 can be raised by many conditions other than cancer, and can be normal in early ovarian cancer.