What is a CA 19-9 blood test?
This test measures the amount of a protein called CA 19-9 (cancer antigen 19-9) in the blood. CA 19-9 is a type of tumor marker. Tumor markers are substances made by cancer cells or by normal cells in response to cancer in the body.
Healthy people can have small amounts of CA 19-9 in their blood. High levels of CA 19-9 are often a sign of pancreatic cancer. But sometimes, high levels can indicate other types of cancer or certain noncancerous disorders, including cirrhosis and gallstones.
Because high levels of CA 19-9 can mean different things, the test is not used by itself to screen for or diagnose cancer. It can help monitor the progress of your cancer and the effectiveness of cancer treatment.
Other names: cancer antigen 19-9, carbohydrate antigen 19-9
What is it used for?
A CA 19-9 blood test may be used to:
- Monitor pancreatic cancer and cancer treatment. CA 19-9 levels often go up as cancer spreads, and go down as tumors shrink.
- See if cancer has returned after treatment.
The test is sometimes used with other tests to help confirm or rule out cancer.
Why do I need a CA 19-9 test?
You may need a CA 19-9 blood test if you've been diagnosed with pancreatic cancer or another type of cancer related to high levels of CA 19-9. These cancers include bile duct cancer, colon cancer, and stomach cancer.
Your health care provider may test you on a regular basis to see if your cancer treatment is working. You may also be tested after your treatment is complete to see if cancer has come back.
What happens during a CA 19-9 blood test?
A health care professional will take a blood sample from a vein in your arm, using a small needle. After the needle is inserted, a small amount of blood will be collected into a test tube or vial. You may feel a little sting when the needle goes in or out. This usually takes less than five minutes.
Will I need to do anything to prepare for the test?
You don't need any special preparations for a CA 19-9 blood test.
Are there any risks to the test?
There is very little risk to having a blood test. You may have slight pain or bruise at the spot where the needle was put in, but most symptoms go away quickly.
