CA 19-9 blood test
Cancer antigen 19-9
In short
A typical adult CA 19-9 result is under 37 U/mL. A small rise is common and most often comes from the gallbladder, bile ducts, liver or pancreas rather than cancer. When it is used to follow a known condition, the trend over repeat tests matters most. Always read your result against the range printed on your own report.
A substance released by cells of the pancreas, bile ducts and gut.
CA 19-9 is mostly used to follow a known condition over time, most often pancreatic cancer during and after treatment. It is not a good screening test, because many other problems raise it, especially gallbladder and bile-duct problems. About 5 to 10 in 100 people make little or none, so the test does not work for them.
Is my CA 19-9 high or low?
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Typical range
| For | Range | Unit |
|---|---|---|
| Adults | under 37 | U/mL |
Typical ranges for adults. Labs differ a little, so the range printed next to your result is the one to go by.
If your CA 19-9 is high
A small rise is common and most often comes from the gallbladder, bile ducts, liver or pancreas rather than cancer. When it is used to follow a known condition, the trend over repeat tests matters most.
Common reasons
- Gallstones, or a bile duct that is blocked or inflamed
- An inflamed pancreas (pancreatitis)
- Liver conditions, such as hepatitis (liver inflammation) or scarring
- Some thyroid, lung, kidney or rheumatic (joint) conditions
- Less often: a cancer of the pancreas, bile ducts or gut, or its return
What can throw it off
A blocked bile duct can push CA 19-9 very high, and it usually falls once the blockage clears.
Questions to take to your appointment
- 1Is this test being used to follow something, or was it a one-off?
- 2Could a gallbladder or bile-duct problem explain it?
- 3Do my liver tests point the same way?
Read together with
Doctors rarely read CA 19-9 alone. These usually sit next to it.
Quick answers
What is the CA 19-9 blood test?
CA 19-9 (Cancer antigen 19-9): A substance released by cells of the pancreas, bile ducts and gut. CA 19-9 is mostly used to follow a known condition over time, most often pancreatic cancer during and after treatment. It is not a good screening test, because many other problems raise it, especially gallbladder and bile-duct problems. About 5 to 10 in 100 people make little or none, so the test does not work for them.
What is a normal CA 19-9 level?
For most adults, CA 19-9 is typically under 37 U/mL. Labs differ a little, so the range printed next to your result is the one to go by.
What does a high CA 19-9 mean?
A small rise is common and most often comes from the gallbladder, bile ducts, liver or pancreas rather than cancer. When it is used to follow a known condition, the trend over repeat tests matters most. Common reasons include gallstones, or a bile duct that is blocked or inflamed; an inflamed pancreas (pancreatitis); liver conditions, such as hepatitis (liver inflammation) or scarring; and some thyroid, lung, kidney or rheumatic (joint) conditions. A doctor reads it together with your other results and how you feel.
What can affect my CA 19-9 result?
A blocked bile duct can push CA 19-9 very high, and it usually falls once the blockage clears.
What should I ask my doctor about my CA 19-9?
Questions worth taking to the appointment: Is this test being used to follow something, or was it a one-off? Could a gallbladder or bile-duct problem explain it? Do my liver tests point the same way?
What this page can’t do
It reads each number on its own.
Doctors read results together — ALT with AST, ferritin with hemoglobin, TSH with free T4. A pattern says more than any single flag.
It doesn't know you.
Your age, your medicines, how you feel and your last result all change what a number means.
It doesn't remember.
Close this page and your results are gone. That's on purpose: nothing was ever sent to us.
We also make Vita: Health Coach, an app for those parts. It reads your whole report with your medicines and history in mind, answers follow-up questions in plain words, and keeps your reports in one place — for you and for the people you look after.
Vita: Health Coach on the App StoreSources
- MedlinePlus — CA 19-9 blood test (pancreatic cancer)
- Cleveland Clinic — CA 19-9 blood test
- ABIM — Laboratory test reference ranges (January 2026)
Stuck on a word? See the medical words. How we choose our sources. More about Vita Health Coach.