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Antimitochondrial Antibody and Antimitochondrial M2 Antibody

Does this test have other names?

AMA, mitochondrial antibody, antimitochondrial M2 antibody

What is this test?

This test looks for substances called antimitochondrial antibody and antimitochondrial M2 antibody in your blood.

These substances are usually made by your body if you have a condition called primary biliary cirrhosis (PBC). PBC is the most common autoimmune disease that affects the liver. In autoimmune diseases, the immune system attacks organs or tissues in the body. Antimitochondrial antibody is found in nearly 19 in 20people with PBC.

PBC causes damage to ducts in the liver that drain away fluid called bile. As a result bile builds up in the liver. This scars the liver. This scarring keeps the liver from working as it should. Over time, it causes liver failure.

PBC is especially common in middle-aged women. It often strikes along with other autoimmune diseases, especially Sjögren's syndrome.

PBC is usually diagnosed and treated early in the course of the disease. This is good, because early treatment can slow down liver scarring. It keeps liver failure from happening for a longer time.

Why do I need this test?

You may have this test if you have symptoms of PBC. Symptoms include:

  • General tiredness (fatigue)

  • Itching

  • Belly (abdominal) pain

  • Nausea

  • Poor appetite

  • Bone, muscle, and joint pain

  • Weight loss

  • Yellowing of the skin and the whites of the eyes, and dark urine (jaundice)

  • Dry eyes and mouth. These are symptoms of Sjögren's syndrome.

  • Buildup of fluid in your ankles and abdomen

You may also have this test if your healthcare provider thinks you have hepatitis. Hepatitis is a swelling of the liver.

What other tests might I have along with this test?

Your healthcare provider may also order other tests to confirm that you have PBC. These tests include:

  • Liver panel blood test. This looks for higher than normal liver enzyme levels.

  • Liver biopsy

  • Cholesterol blood test

  • Abdominal ultrasound

  • MRI scan

What do my test results mean?

Many things may affect your lab test results. These include the method each lab uses to do the test. Even if your test results are different from the normal value, you may not have a problem. To learn what the results mean for you, talk with your healthcare provider.

A normal range for this test is below a 1:20 titer. Titer refers to the portion of the antibody in your blood.

If your results are higher, it may mean that you have PBC. Higher results may also be caused by:

  • Hepatitis

  • Syphilis

  • Tuberculosis

  • Heart disease

  • Other chronic liver diseases

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your arm.

Does this test pose any risks?

Taking a blood sample with a needle carries risks that include bleeding, infection, bruising, or feeling dizzy. When the needle pricks your arm, you may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.

What might affect my test results?

Certain medicines can affect your results.

How do I get ready for this test?

You don't need to prepare for this test. But be sure your healthcare provider knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illegal drugs you may use. 


Online Medical Reviewer: Chad Haldeman-Englert MD
Online Medical Reviewer: Kenny Turley PA-C
Online Medical Reviewer: L Renee Watson MSN RN
Date Last Reviewed: 4/1/2019
© 2000-2021 The StayWell Company, LLC. All rights reserved. This information is not intended as a substitute for professional medical care. Always follow your healthcare professional's instructions.
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