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.

PBC causes damage to ducts in the liver that drain away fluid called bile. As a result, bile builds up in the liver, scarring the organ. This scarring prevents proper liver function and eventually leads to liver failure.

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

PBC is usually diagnosed and treated early in the disease process, which is preferable because early treatment can slow down liver scarring and postpone liver failure.

Why do I need this test?

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

  • General fatigue

  • Itching

  • Jaundice, or yellowing of the skin and the whites of the eyes, and dark urine

  • Dry eyes and mouth, which are symptoms of Sjögren's syndrome

You may also have this test if your doctors suspects that you have hepatitis, an inflammation of the liver.

What other tests might I have along with this test?

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

  • Alkaline phosphatase blood test

  • Liver biopsy

  • Cholesterol blood test

  • Abdominal ultrasound

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 health care provider.

A normal range for this test is below a 1:20 titer. Titer refers to the concentration 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 medications 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 doctor knows about all medicines, herbs, vitamins, and supplements you are taking. This includes medicines that don't need a prescription and any illicit drugs you may use.