CA 19-9 is a type of tumor marker used in the diagnosis and monitoring of certain types of cancers, particularly pancreatic cancer. Tumor markers are substances produced by cancer cells or by normal cells in response to the presence of cancer in the body. They can be detected in blood or other body fluids and can help doctors diagnose cancer, determine the stage of the disease, and monitor the effectiveness of treatment.
CA 19-9 is a glycoprotein antigen that is commonly found in the blood of people with pancreatic cancer, as well as some other types of cancer, such as bile duct and gastric cancer. Elevated levels of CA 19-9 in the blood may suggest the presence of cancer, although this marker is not specific to cancer and can also be elevated in other conditions, such as pancreatitis and cirrhosis.
CA 19-9 is measured using a blood test, and the results are reported in units per milliliter (U/mL). The normal range for CA 19-9 varies depending on the laboratory and the method used to measure it, but in general, levels above 37 U/mL are considered abnormal. However, it is important to note that a normal CA 19-9 level does not necessarily rule out the presence of cancer.
While CA 19-9 can be a useful tool in the diagnosis and management of pancreatic cancer, it is important to use it in conjunction with other tests and imaging studies, as well as a thorough medical history and physical examination.