What is a CA-125 Test?
A CA-125 test is a simple blood test that measures the level of CA-125 protein in your blood. CA-125, also known as cancer antigen 125, is a biomarker—a substance whose presence indicates a particular condition or disease. While elevated CA-125 levels are often associated with ovarian cancer, it's crucial to understand that a high level doesn't automatically confirm cancer.
The test measures the amount of CA-125 protein in a blood sample. This protein is frequently found on the surface of ovarian cancer cells, but it can also be present in some normal tissues. Therefore, the test results must be interpreted cautiously, in conjunction with other diagnostic tools and clinical findings.
Uses of the CA-125 Test
The CA-125 test has several applications:
- Monitoring Ovarian Cancer: The test is commonly used to monitor the response of ovarian cancer to treatment. A decreasing CA-125 level often indicates that the treatment is effective. [Source: MedlinePlus, Mayo Clinic]
- Diagnosis of Ovarian Cancer (with limitations): While not a definitive diagnostic tool on its own, a high CA-125 level may raise suspicion for ovarian cancer, prompting further investigation. [Source: WebMD, Cancer Research UK]
- Monitoring Other Cancers: Elevated CA-125 levels can sometimes be seen in other cancers like fallopian tube or primary peritoneal cancers. [Source: Macmillan Cancer Support]
Interpreting CA-125 Test Results
A normal CA-125 level is generally considered to be between 0-35 units/mL. However, a high CA-125 level doesn't always mean cancer. Many other conditions, including endometriosis, fibroids, and pregnancy, can also elevate CA-125. [Source: Ocrahope] Conversely, some women with ovarian cancer may have normal CA-125 levels.
- High CA-125 Level: Requires further investigation with imaging tests like ultrasounds, CT scans, or MRIs, as well as a thorough medical history review and pelvic exam to determine the cause.
- Low CA-125 Level: Doesn't necessarily mean there is no cancer. A low level after treatment may indicate that the treatment is successful. However, persistent symptoms should still be reported to a physician. [Source: Target Ovarian Cancer]
The CA-125 test is an important tool in the management of ovarian cancer and related conditions, but it should be interpreted within the context of a complete clinical evaluation. It is not a standalone diagnostic test. [Source: Canadian Cancer Society, StatPearls]
