Cancer antigen 125 (CA 125) is a protein that is found on the surface of some types of cancer cells, including ovarian, endometrial, and pancreatic cancer cells. It can also be present in benign conditions, such as uterine fibroids and endometriosis. The CA 125 test measures the level of this protein in the blood and is commonly used as a tumor marker for certain types of cancer.
The CA 125 test is not used as a screening test for cancer, but rather as a diagnostic tool for individuals who already have symptoms or signs of cancer. It may also be used to monitor the progression of cancer or to check for recurrence after treatment.
Although the CA 125 test can be useful in the diagnosis and management of certain cancers, it is not a perfect test and has some limitations. For example, some people with cancer may not have elevated levels of CA 125, and some people without cancer may have elevated levels of CA 125 due to other factors. Additionally, the test is not specific to any one type of cancer and can be elevated in a variety of cancers and non-cancerous conditions.
The interpretation of CA 125 test results should always be done in conjunction with other clinical information, such as imaging studies and physical exam findings. In some cases, additional testing, such as a biopsy, may be necessary to confirm a cancer diagnosis.
Overall, the CA 125 test is a useful tool in the management of certain types of cancer, but it should be used in combination with other diagnostic and monitoring techniques to ensure accurate diagnosis and treatment.