What is the CA-125 blood test?
CA-125 is known by various other names such as ovarian cancer antigen and CA-125 tumor marker. It is a protein present on the surface of most (but not all) ovarian cells. Thus, significantly high levels of CA-125 may be seen in the blood of patients with ovarian cancer. Because all types of ovarian cancer do not possess this protein, not all women with ovarian cancer will have high levels of CA-125 in their blood.
CA-125 may be elevated in several noncancerous conditions such as:
- Liver disease
- Menstrual period
- Uterine fibroid
- Pelvic inflammatory disease (PID)
Hence, elevated CA-125 levels do not mean that the patient surely has ovarian cancer. Doctors do not recommend the CA-125 blood test for screening women with low to moderate ovarian cancer risk. The test, nonetheless, does have several important uses such as:
- Monitoring the response to treatment for ovarian cancer (declining CA-125 levels generally mean that the tumor is responding to the treatment)
- Finding out whether the tumor has returned after successful treatment
- Screening women with a high risk of ovarian cancer such as those who have certain abnormal genes, namely, BRCA and BRCA2 genes, or the gene associated with Lynch syndrome or Peutz-Jeghers syndrome; those with a history of cancer of the breast, colon or uterus or those with a family history of ovarian cancer, breast cancer or colorectal cancer (this means any of the first-degree relatives such as mother, sister, grandmother or daughter have had any of these cancers)
The CA-125 blood test is a simple test during which a health professional collects a blood sample from a vein in the patient’s arm by using a small needle. The collection hardly takes five minutes, and the patient does not need to make any special preparation for the test. They may experience slight stinging when the needle goes in and out of their skin. They may also have little pain or bruising at the needle site, but it goes away on its own without generally causing any significant discomfort. The doctor will assess their test results and may refer them to a gynecologist if needed.