Do I need a Cancer Antigen 19.9 test?

Are you wondering what a Cancer Antigen 19.9 test can tell you about your health? If you've been diagnosed with certain cancers or are tracking your wellbeing after treatment, understanding this marker may help you stay informed about what's happening in your body.

CA 19-9 is a protein that some cancer cells produce, particularly those in the pancreas and bile ducts, though normal digestive cells can make it too. A CA 19-9 test measures the level of this protein in your blood.

Knowing your CA 19-9 level can empower you to have better conversations with your healthcare team about your health journey. This biomarker is especially useful for tracking cancer progression and response to treatment over time, rather than for initial screening. By understanding your results as part of Listen Health's comprehensive cancer indicator panel, you're taking an active role in monitoring your wellbeing.

Cancer Antigen 19.9 — Key Facts
MeasuresA protein made by some cancer cells, especially those in the pancreas and bile ducts.
CategoryCancer Indicators
Unitpositive / negative
Tested inListen Health Standard & Premium membership (100+ biomarkers)
Reviewed byDr Jamie Deans, MBChB

What is it?

CA 19-9 is a protein made by some cancer cells, especially those in the pancreas and bile ducts. It can also be produced by normal cells in the digestive system. Doctors use the CA 19-9 test to help track cancer, especially after diagnosis and during treatment. CA 19-9 is not used to screen for cancer in healthy people, because it can be high for many reasons, including non-cancerous conditions like pancreatitis, gallstones, liver disease, and even after some infections or vaccinations. Some people have a genetic type (Lewis antigen negative) that means they do not make CA 19-9, even if they have cancer.

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Why does it matter?

CA 19-9 is most useful for monitoring cancer that has already been diagnosed. If cancer is present, rising CA 19-9 levels may mean the tumor is growing or treatment is not working. Falling levels may mean the tumor is shrinking or treatment is working. Stable levels can mean the disease is not changing. However, high CA 19-9 does not always mean cancer is present, and normal levels do not always mean cancer is absent. CA 19-9 can be falsely high in benign conditions, especially with bile duct blockage or inflammation. It is important to interpret CA 19-9 results with other tests, scans, and symptoms.

References

Frequently Asked Questions

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AHPRA Disclaimer: This information is general in nature and should not replace individual medical advice. Always discuss your test results and health concerns with a registered healthcare practitioner.