CA 19-9 Blood Test - More Information

The CA 19-9 test, also known as a CA 19-9 blood test, carbohydrate antigen 19-9 test and CA 19-9 lab test, measures the CA 19-9 blood level.

CA 19-9 is a blood marker that is sometimes tracked in people with cancer of the pancreas. Also called cancer antigen 19-9 and sialyated Lewis (a) antigen, CA 19-9 is named from how it binds to a specific tumor marker.

Many cancer organizations recommend using CA 19-9 as more of a tracking (rather than screening) marker for pancreatic cancer. Used in this way, CA 19-9 blood levels should decrease as a pancreatic tumor decreases in size as CA 19-9 is typically released by the pancreas. CA 19-9 levels can be elevated in other types of gastrointestinal cancers as well as bile duct disease. A small percentage of people do not produce CA 19-9. CA 19-9 lab results are typically reported in U/mL units.

To get a CA 19-9 test near you, order online and get tested at the Quest Diagnostics location you selected to get your blood drawn. Once your CA 19-9 lab results are ready, they will be available for download. As can be seen on the sample CA 19-9 lab report above, the CA 19-9 blood level is reported as a number and can be compared against the reference range provided by the lab.

The CA 19-9 level is also sometimes used to monitor for disease activity or to assess the risk of relapse following treatment. CA 19-9 blood levels cannot be used in isolation as absolute evidence of the presence or absence of a disease and all results should be evaluated in conjunction with a licensed medical provider. The CA 19-9 blood test is sometimes ordered with other cancer markers such as the AFP test and the CEA test.