Carbohydrate Antigen (CA) 19-9 Blood Test
The Carbohydrate Antigen (CA) 19-9 Blood Test is used primarily to monitor response to pancreatic cancer therapy and to monitor recurrence, sometimes to help diagnose pancreatic cancer. However, CA 19-9 may also be elevated with the presence of other cancers.
This test looks for the CA 19-9 antigen in your blood. Antigens are substances that stimulate your body's immune system. Some cancer cell types send the CA 19- 9 antigen into the blood, which can be used to measure this quantity.
High CA 19-9 levels are mainly due to pancreatic cancer. However, it can also be caused by other cancers and diseases such as gallbladder and bile duct cancers (cholangiocarcinoma), colorectal cancer, gastric cancer, ovarian cancer, lung cancer, liver cancer, bile duct obstruction (e.g., gallstones), pancreatitis, cystic fibrosis, thyroid and liver disease. Antigens such as CA 19-9 which provide information on cancer are called tumor markers. This test is not used as a screening test for cancer.
Applicable reasons for having this test performed may include:
- Post-treatment to ensure the cancer has not returned.
- A cancer risk due to symptoms or the family history of cancer. This test together with other tests may assist in a diagnosis.
- Undergoing cancer treatment.
- Monitoring the effectiveness or progression of cancer treatment.
This test is best used to diagnose or decide on pancreatic cancer treatment, but can also be used for other cancers.
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