Cancer Antigen 19.9 (CA 19.9) Test

Cancer antigen 19-9 or CA 19-9 is a protein present in the body as a tumour marker. Tumour markers are those substances that cancer cells make or normal cells make in response to cancer developing in your body.

Healthy people usually have normal levels of CA 19-9 in their blood. High levels of CA 19-9 often indicate pancreatic cancer. One may have high levels of CA 19-9 in other types of cancers like stomach cancer, colon cancer, bile duct cancer and in certain noncancerous conditions like liver cirrhosis and gallstones.

The CA 19-9 Test helps detect the amount of the protein CA 19-9 in the blood. However, this test can only be used to screen for the presence of cancer. It cannot be used to diagnose cancer alone. You will need a set of other tests to confirm the diagnosis. The CA 19-9 Test helps monitor the progress of cancer and the effectiveness of your ongoing treatment. It also helps detect if cancer has relapsed after treatment.

The CA 19-9 Test is required for the following reasons -

a.        Diagnosis of cancer and other medical conditions

CA 19-9 is raised in cases of pancreatic cancer and other cancers like bile duct cancer, colon cancer and stomach cancer. It can also increase due to liver cirrhosis and gallstones. The CA 19-9 Test is not a diagnostic test for these conditions, but it helps detect a problem. This test is usually combined with other tests like imaging and biopsy to confirm the diagnosis.

b.   Evaluate cancer therapy

If you have already been diagnosed with cancer, periodic monitoring of the Cancer Antigen 19-9 can help evaluate how your cancer responds to the treatment. The CA 19-9 levels usually go down after proper treatment. The levels are compared to future levels taken during your cancer treatment and after your treatment.

c.        Estimate cancer prognosis

Your levels of CA 19-9 before and after your cancer treatment help identify the time required for cancer treatment. Your doctor can give you an estimate of the probable outcome of your disease with the help of the CA 19-9 Test.

d.   Monitor for cancer relapse

After you have completed your cancer treatment, whether surgical or medical or both, you need to check for evidence of recurrence. Cancers can relapse over time and may not be detected right away. In such cases, the CA 19-9 Test procedure helps detect if there is an underlying cause for cancer.

Other names of CA 19-9 Test

• CA 19-9 Assay
• CA 19-9 Radioimmunoassay
• Cancer Antigen 19-9
• Cancer-Associated Antigen 19-9
• Carbohydrate Antigen 19-9

What does the CA 19-9 Test measure?

The CA 19-9 Test measures the level of Cancer Antigen 19-9 or CA 19-9 in the blood. CA 19-9 is a protein that is present in your body. This protein is produced by your healthy cells as a response to cancer in the body as well as certain types of cancer cells.

Who is the CA 19-9 Test prescribed for?

The CA 19-9 Test is prescribed for adults of both genders. This test is prescribed in the following cases -

• If you are at a high risk of developing cancer.
• If you have a history or a family history of cancer.
• If you are undergoing cancer treatment.
• If you have been treated for cancer in the past and need to check for relapse.

The CA 19-9 Test results are usually reported in units per millilitre (U/mL). If you have gotten other liver function tests done, then you will get the reports of all parameters.

The results of the CA 19-9 Test give you a report of abnormal levels of CA 19-9 in the blood.

 Normal CA 19-9 Test ranges may vary depending on the laboratory.

• Normal CA 19-9 levels less than 37 U/mL indicate that you do not have cancer.
• CA 19-9 levels of more than 37 U/mL indicate that you may have cancer of the pancreas, gallbladder, colon, lung, liver or stomach. You may need to undergo a series of diagnostic tests to confirm the cancer diagnosis.
• CA 19-9 levels between 37 - 75 U/mL indicate an infection of the pancreas like pancreatitis, gallbladder infection, liver disease, gallstones or cystic fibrosis.

If you are on cancer treatment and you get your CA 19-9 Test done, the CA 19-9 Test results could mean the following -

• High CA 19-9 levels during treatment - Treatment is not working yet.
• Normal CA 19-9 levels during treatment - Treatment has started working.
• CA 19-9 levels are Normal at first and then become higher - Treatment was working, but the cancer has recurrence now.

Based on your CA 19-9 test results, the doctor may require other liver profile tests to confirm the clinical diagnosis.

The CA 19-9 test requires a sample of your blood. This test is usually combined with other regular tests.

CA 19-9 test preparation 

The CA 19-9 Test takes a sample of your blood for testing. It does not require any special preparation. However, if you are getting other blood tests done along with the CA 19.9 Test, you may be asked to not eat or drink anything for 10-12 hours based on the tests.

a. Before the CA 19-9 Test

This test does not require any preparation from your end.

b. During the CA 19-9 Test

It is a simple blood test that will get over in 5-10 minutes. You do not need to prepare for the test in any way.

c. After the CA 19-9 Test

There are no restrictions after the CA 19-9 Test. Therefore, you can resume regular activity after the test.

Test inclusions: What parameters are included in the CA 19-9 Test?

The parameters included in the CA 19-9 Test are the measures of the levels of CA 19-9, a tumour marker protein, in the blood. If your doctor orders other tests like liver function tests or hormonal profiles, then you may get to see all parameters of your liver and pancreas.

How frequently should you take the CA 19-9 Test?

Your doctor may repeat the CA 19-9 Test based on your diagnosis and symptoms. If you start your treatment for pancreatic cancer or other cancers, the CA 19-9 Test may be repeated every 3-4 weeks to check if the treatment is working. Regular monitoring and testing allow your doctor to check the prognosis of your disease and how you are responding to the treatment. In addition, follow-up tests of the CA 19-9 Test help provide detailed information about the severity of the disease and how the disease has progressed over time.

If you have completed your course of treatment, your doctor may repeat the CA 19-9 Test every year to check for relapse of cancer.

Pancreatic cancer, Cholangiocarcinoma, Cirrhosis, Cholestasis, Pancreatitis, Colon cancer