CA-125 Blood Test (Ovarian Cancer)
This test measures the amount of a protein called CA-125 (cancer antigen 125) in a sample of your blood.
This test measures the amount of a protein called CA-125 (cancer antigen 125) in a sample of your blood. CA-125 is a type of tumor marker. Tumor markers are substances that are often made by cancer cells or by normal cells in response to cancer. Organs in the female reproductive system (such as the ovaries and fallopian tubes) may make CA-125 when those organs are inflamed. This may happen in response to normal bodily functions, such as a menstrual period . However, your body may also produce high levels of CA-125 in response to ovarian cancer . The ovaries are a pair of female reproductive glands that store ova (eggs) and make female hormones . Ovarian cancer happens when the cells in an ovary begin to grow out of control. Other names: cancer antigen 125, glycoprotein antigen, ovarian cancer antigen, CA-125 tumor marker
Why is this test ordered? If you've been diagnosed with ovarian cancer , you may have several CA-125 blood tests: During your treatment to see if your cancer is going away. After your treatment, to check if your cancer has returned. If you have a lump in your pelvis that could be ovarian cancer , your provider may use a CA-125 test to help find out if it could be ovarian cancer. But only a biopsy can diagnose ovarian cancer. If you have a very high risk of getting ovarian cancer , your provider may suggest checking your CA-125 levels. If they're high, you'll probably need more tests to find out if you have cancer. You're more likely to get ovarian cancer if you: Have a mother or sister, or two or more other relatives who've had ovarian cancer. Have family members who've had breast cancer or colorectal cancer (colon cancer). Have inherited certain gene changes or conditions that increase your risk of ovarian cancer, such as: Changes in your BRCA 1 or BRCA 2 genes. Lynch syndrome (also called hereditary non-polyposis colorectal cancer), an inherited disorder that increases the risk for many types of cancer. Have had breast, uterine (uterus), or colorectal cancer. If you're concerned about getting ovarian cancer, talk with your provider about your risk.
Clinical Interpretation
Your provider will review your CA-125 test results along with other information about your condition. Together, you can discuss how your results affect your diagnosis, treatment, and need for more testing. In general: If you are being treated for ovarian cancer , and the results of several tests show that your CA-125 levels are going down, it usually means that the treatment is helping. If your levels go up or stay the same over time, it may mean that the treatment isn't working. If you have finished your treatment for ovarian cancer and your CA-125 levels begin to increase over time, your cancer may be coming back. If you have a high risk for ovarian cancer or have a suspicious pelvic lump , high CA-125 levels could be a sign of cancer. Your provider will usually order more tests to make a diagnosis. While high CA-125 levels don't always mean ovarian cancer, a normal CA-125 test result doesn't rule it out. That's because CA-125 levels may be low in the early stages of cancer. And not everyone with ovarian cancer makes high levels of CA-125. Talk with your provider if you have questions about your results. Learn more about laboratory tests, reference ranges, and understanding results .
Related ICD-10 Codes
Clinical Protocol & Patient Advice
- 1
You don't need any special preparations for a CA-125 blood test.
Usage Guidance
- Reference ranges vary by laboratory. Always discuss your specific results with a qualified healthcare professional.
Source: MedlinePlus, National Library of Medicine. View the original.