Results of the CA 125 test are measured in units per milliliter (U/mL). The normal range for CA 125 is less than 35 U/mL.
If your CA 125 level is higher than normal, your doctor will likely repeat the test. You may have a benign condition, or the test result could mean that you have ovarian, endometrial, peritoneal or fallopian tube cancer. But CA 125 is not a definitive diagnostic test for cancer, so your doctor will evaluate the results along with those of other tests that may be ordered.
If you've been previously diagnosed with ovarian, endometrial, peritoneal or fallopian tube cancer, a decreasing CA 125 level often indicates that the cancer is responding to treatment. A rising CA 125 level may indicate a return or continued growth of the cancer.
For specific information about what your CA 125 test results mean, talk with your doctor.
Apr. 16, 2011
- CA-125. Lab Tests Online. http://labtestsonline.org/understanding/analytes/ca125/. Accessed March 2, 2011.
- Carlson KJ. Screening for ovarian cancer. http://www.uptodate.com/home/index.html. Accessed March 2, 2011.
- Clarke-Pearson DL. Screening for ovarian cancer. New England Journal of Medicine. 2009;361:170.
- Understanding CA 125 levels: A guide for ovarian cancer patients. Gynecologic Cancer Foundation. http://www.wcn.org/downloads/CA125levels.pdf. Accessed March 2, 2011.
- Tumor markers: Questions and answers. National Cancer Institute. http://www.cancer.gov/cancertopics/factsheet/detection/tumor-markers. Accessed March 2, 2011.
- How is endometrial cancer diagnosed? American Cancer Society. http://www.cancer.org/Cancer/EndometrialCancer/DetailedGuide/endometrial-uterine-cancer-diagnosis. Accessed March 2, 2011.
- Stany MP, et al. Clinical decision making using ovarian cancer risk assessment. AJR. 2010;194:337.
- Memarzadeh S, et al. Cancer of the fallopian tube. http://www.uptodate.com/home/index.html. Accessed March 2, 2011.
- Goff B. Early detection of epithelial ovarian cancer: Role of symptom recognition. http://www.uptodate.com/home/index.html. Accessed March 2, 2011.
- Rustin GJS, et al. Early versus delayed treatment of relapsed ovarian cancer (MRC OV05/EORTC 55955): A randomised trial. The Lancet. 2010;376:1155.
- Ovarian cancer: Can ovarian cancer be found early? American Cancer Society. http://www.cancer.org/Cancer/OvarianCancer/DetailedGuide/ovarian-cancer-detection. Accessed March 2, 2011.
- Ovarian cancer: Common questions about symptoms and screening. American Cancer Society. http://www.cancer.org/Cancer/news/ovarian-cancer-why-screening-isnt-routine?ssDomain. Accessed March 2, 2011.
- Laboratory reference values. CA 125. Rochester, Minn.: Mayo Foundation for Medical Education and Research; Feb. 2011.
- Bast RC. CA 125 and the detection of recurrent ovarian cancer. Cancer. 2010;116:2850.