CA 19-9 Blood Test (Pancreatic Cancer) Test
The CA 19-9 blood test measures a protein called CA 19-9, a tumor marker that can be high in certain cancers and other conditions. It is used mainly to monitor cancer treatment and check for cancer recurrence, not to screen or diagnose cancer by itself.
What this test measures
A CA 19-9 test measures the amount of a protein called CA 19-9 (cancer antigen 19-9) in a sample of your blood. CA 19-9 is a type of tumor marker, which are substances made by cancer cells or by normal cells in response to cancer.
What your results mean
Reference ranges vary by laboratory and by your age and sex. MedlinePlus does not publish a single normal range for this test — always read your result against the range printed on your own lab report and discuss it with your provider.
Higher-than-normal results
High levels of CA 19-9 can be a sign of certain cancers of the digestive tract, including pancreas, bile duct, colon, rectum, stomach, ovaries, and bladder. However, high levels can also be a sign of other conditions such as gallstones, cholangitis, pancreatitis, cirrhosis, liver disease, and cystic fibrosis. Healthy people can also have high levels without needing treatment.
Frequently asked questions
What is a CA 19-9 test used for?
According to MedlinePlus, a CA 19-9 test is used to monitor certain cancers and cancer treatment, help make a prognosis, check whether cancer has returned after treatment, and check for certain cancers when used with other tests.
Can a CA 19-9 test diagnose cancer by itself?
No. MedlinePlus states that health care providers do not use the results from a CA 19-9 test alone to screen for or diagnose cancer or other diseases. They must consider the results along with other tests.
What does a high CA 19-9 level mean?
High levels can be a sign of certain cancers of the digestive tract, such as pancreatic, bile duct, colon, rectal, stomach, ovarian, and bladder cancers. But they can also be caused by non-cancer conditions like gallstones, pancreatitis, cirrhosis, and cystic fibrosis.
What does a decreasing CA 19-9 level mean during cancer treatment?
According to MedlinePlus, decreasing levels may mean your tumor is shrinking and your treatment is working.
Can someone have cancer but still have normal CA 19-9 levels?
Yes. MedlinePlus notes that some people do not make CA 19-9 even when they have a cancer that usually produces high levels. For these people, a CA 19-9 test is not useful.
Related lab tests
Sources
- MedlinePlus: CA 19-9 Blood Test (Pancreatic Cancer) — NIH MedlinePlus
Last updated . Information is aggregated from official public sources and is not a substitute for professional medical care.