What is this test?
CA 19-9 is a substance that can be elevated in certain diseases of the pancreas, bile ducts and digestive system. It is mainly used for follow-up in an appropriate clinical context.
Why might it be ordered?
- To monitor response to treatment or change in an established disease.
- As supporting information alongside imaging findings or symptoms when requested by a specialist.
What sample is needed?
A healthcare professional collects a venous blood sample. Depending on the method, the laboratory uses serum or plasma.
How should you prepare?
Tell the laboratory about all medicines, hormone treatments, vitamins and supplements you take. Do not stop or change treatment unless your clinician tells you to. Follow any instructions about fasting and the time of collection.
How should you understand the result?
There may be an increase in blockage or inflammation of the bile ducts, pancreatitis, liver and other benign conditions. A trend across consecutive measurements made with a comparable method is often more informative than a single value.
Sources and editorial status
This patient-facing text is an editorial draft. It should be approved by a laboratory physician before official publication.