CA 125 Test
Before starting therapy for ovarian cancer or if at high risk for developing ovarian cancer, and at intervals during and after treatment. CA 125 may also be request by your GP if you have persistent or frequent symptoms that may be caused by ovarian cancer.
A blood sample taken from a vein in the arm
CA 125 is a protein often found on the surface of ovarian cancer cells and in some normal tissues. It is used as a marker for ovarian cancer. However, CA 125 levels may also be high in other types of non-cancerous conditions, including menstruation, pregnancy, and pelvic inflammatory disease.
How is the sample collected for testing?
Blood is taken from a vein in the arm.
Is any test preparation needed to ensure the quality of the sample?
How is it used?
CA 125 is mainly used to monitor therapy during treatment for ovarian cancer. CA 125 is also used to detect whether cancer has come back after treatment is complete. This test is sometimes used to follow women who are at high-risk because they have a family history of ovarian cancer but who do not yet have the disease. CA 125 is also recommended together with pelvic ultrasonography in women aged over 50 years who have persistent, continuous or worsening unexplained tummy pain, bloating, feeling full and/or loss of appetite or problems with urination and in whom a doctor is concerned about a possible ovarian cancer after examining the tummy.
When is it requested?
Before a patient starts treatment for ovarian cancer, the doctor will measure CA 125 to be able to compare it with future measurements. During therapy, doctors use CA 125 testing, at intervals, to follow the response to therapy. CA 125 may also be measured several times after therapy is completed to catch any early signs of the cancer’s return.CA 125 may also be requested by your GP if you have persistent or frequent symptoms (e.g. unexplained tummy pain, bloating, feeling full and/or loss of appetite or problems with urination) to determine if you require an ultrasound scan of the abdomen and pelvis.
What does the test result mean?
If CA 125 levels fall during therapy, this generally indicates that the cancer is responding to treatment. If CA 125 levels rise, the cancer may not be responding to treatment. High CA 125 levels after treatment is complete may indicate that the cancer has come back. In women without a diagnosis of ovarian cancer a raised CA 125 may indicate the need for an ultrasound of the abdomen and pelvis.
Is there anything else I should know?
A CA 125 result that is higher than normal does not always mean a patient has ovarian cancer. CA 125 can be high in many normal or benign conditions (for example, pregnancy, menstruation, uterine fibroids, endometriosis and pelvic inflammatory disease). A CA 125 test isn't accurate enough to use for ovarian cancer screening in the general population, because many noncancerous conditions (such as those described above) can increase the CA 125 result..
Is CA125 always increased in ovarian cancer?
My CA 125 is elevated. Does it mean I have cancer?
Does ovarian cancer run in families?
Family history is a risk factor for ovarian cancer. If you have close family members who have had ovarian cancer, you are at higher risk than someone who has no family history of the disease. Make sure your doctor knows about your family medical history.
If you have a strong family history of ovarian cancer or you have the BRCA1 or BRCA2 gene mutation, your doctor may recommend a CA 125 test as one way to screen for ovarian cancer.
On This Site
Tests: BRCA-1 and BRCA-2, Tumour Markers
Conditions: Ovarian cancer
News item: Ovarian cancer diagnosed following NICE recommendation for CA125 testing