CA 19-9 Blood Test (Pancreatic Cancer)
Reviewed
A CA 19-9 blood test measures the level of a tumor marker protein in your blood. It is mainly used to monitor certain cancers of the digestive tract (especially pancreatic cancer), assess treatment effectiveness, help predict prognosis, and detect recurrence. It is not used alone for screening or diagnosis.
Preparation and collection
No special preparation is usually needed. However, ask your provider if you need to stop taking certain vitamins before the test.
Understanding this test
Use the reference interval and units printed by the laboratory that performed the test. A result outside that interval is not a diagnosis by itself, and a result inside it does not rule out every condition. Your symptoms, history, medicines, timing, and related tests can change what the result means.
- High CA 19-9 levels can be caused by noncancerous conditions such as gallstones, pancreatitis, cirrhosis, or liver disease.
- Some people do not produce CA 19-9 even when they have a cancer that usually causes high levels, making the test unhelpful for them.
- Different labs may use different test methods, which can affect results. Consistency in lab testing is important for accurate monitoring.
- A CA 19-9 test cannot be used alone to screen for or diagnose cancer; it must be combined with other tests and clinical evaluation.
What to do next
Discuss your results with your healthcare provider, who will interpret them based on your medical history, other test results, and imaging studies. Additional tests or procedures may be needed to confirm any findings.
Evidence source
U.S. National Library of Medicine: CA 19-9 Blood Test (Pancreatic Cancer)