CA 19-9

Also Known As

Cancer Antigen 19-9

This article was last reviewed on

28 April 2016.

This article waslast modified on 2 November 2020.

At a Glance

Why Get Tested?

To help tell the difference between cancer of the pancreas and bile ducts and other conditions; to monitor response to pancreatic cancer treatment and to watch for recurrence.

When To Get Tested?

When your doctor suspects that you have pancreatic cancer and during or following pancreatic cancer treatment.

Sample Required?

A blood sample is obtained by inserting a needle into a vein in the arm.

Test Preparation Needed?

No test preparation is needed

On average it takes 7 working days for the blood test results to come back from the hospital, depending on the exact tests requested. Some specialist test results may take longer, if samples have to be sent to a reference (specialist) laboratory. The X-ray & scan results may take longer. If you are registered to use the online services of your local practice, you may be able to access your results online. Your GP practice will be able to provide specific details.

If the doctor wants to see you about the result(s), you will be offered an appointment. If you are concerned about your test results, you will need to arrange an appointment with your doctor so that all relevant information including age, ethnicity, health history, signs and symptoms, laboratory and other procedures (radiology, endoscopy, etc.), can be considered.

Lab Tests Online-UK is an educational website designed to provide patients and carers with information on laboratory tests used in medical care. We are not a laboratory and are unable to comment on an individual's health and treatment.

Reference ranges are dependent on many factors, including patient age, sex, sample population, and test method, and numeric test results can have different meanings in different laboratories.

For these reasons, you will not find reference ranges for the majority of tests described on this web site. The lab report containing your test results should include the relevant reference range for your test(s). Please consult your doctor or the laboratory that performed the test(s) to obtain the reference range if you do not have the lab report.

For more information on reference ranges, please read Reference Ranges and What They Mean.

What is being tested?

Cancer antigen 19-9 (CA 19-9) is a protein that exists on the surface of certain cells. CA 19-9 does not cause cancer; rather, it is a protein that is produced by the tumour cells, making it useful as a tumour marker to follow the course of the cancer.

CA 19-9 is elevated in most patients with advanced pancreatic cancer, but it may also be elevated in other cancers and diseases such as bowel cancer, lung cancer and gall bladder cancer, as well as in benign diseases such as gall stones, pancreatitis, cystic fibrosis, and liver disease. Because elevated levels of CA 19-9 are seen in many diseases, elevated levels do not necessary mean the presence of pancreatic cancer. Very small amounts of CA19-9 may also be found in healthy patients.

Common Questions

How is it used?
CA 19-9 is used as a tumour marker:

to help tell the difference between cancer of the pancreas and bile ducts and other non-cancerous conditions, such as pancreatitis;

to monitor a patient's response to pancreatic cancer treatment; and

to look for pancreatic cancer recurrence.
When is it requested?

CA 19-9 may be requested along with other tests, such as carcinoembryonic antigen (CEA), bilirubin, and/or liver function tests, when a patient has symptoms that may indicate pancreatic cancer, including abdominal pain, nausea, weight loss, and jaundice.

If CA 19-9 is initially elevated in pancreatic cancer, then it may be requested several times during cancer treatment to monitor response and, on a regular basis following treatment, to help detect recurrence of the cancer.
What does the test result mean?

Small increases in CA 19-9 levels can be detected in some healthy people, and in many benign conditions that affect the liver or pancreas can cause a temporary rise in CA 19-9.

Moderate to high levels are found in pancreatic cancer, other cancers, and in several other diseases and conditions. The highest levels of CA 19-9 are seen in a condition called excretory ductal pancreatic cancer - cancer that is found in the pancreas tissues that produce food-digesting enzymes and in the ducts that carry those enzymes into the small intestine. This tissue is where 95% of pancreatic cancers are found.

Repeated measurements of CA 19-9 may be useful during and following treatment because rising or falling levels may give your doctor important information about whether the treatment is working, whether all of the cancer was removed successfully during surgery, and whether the cancer is returning.
Is there anything else I should know?
Why is my doctor not screening me for CA 19-9?
What other procedures will my doctor request with my CA 19-9?
What are the main risk factors for pancreatic cancer?

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Cancer Antigen 19-9 (CA 19-9) Test