Antimitochondrial antibody
Antimitochondrial antibodies (AMA) are substances (antibodies) that form against mitochondria. The mitochondria are an important part of cells. They are the energy source inside the cells. These help the cells work properly.
Antibodies
An antibody is a protein produced by the body's immune system when it detects harmful substances, called antigens. Examples of antigens include micr...
This article discusses the blood test used to measure the amount of AMA in the blood.
How the Test is Performed
A blood sample is needed. It is most often taken from a vein. The procedure is called a venipuncture.
Venipuncture
Venipuncture is the collection of blood from a vein. It is most often done for laboratory testing.
How to Prepare for the Test
Your health care provider may tell you not to eat or drink anything for up to 6 hours before the test (most often overnight).
How the Test will Feel
When the needle is inserted to draw blood, some people feel moderate pain. Others may feel only a prick or stinging sensation. Afterward, there may be some throbbing.
Why the Test is Performed
You may need this test if you have signs of liver damage. This test is most often used to diagnose primary biliary cholangitis, formerly called primary biliary cirrhosis (PBC).
Primary biliary cirrhosis
The bile ducts are tubes that move bile from the liver to the small intestine. Bile is a substance that helps with digestion. All of the bile ducts...
The test may also be used to tell the difference between bile system-related cirrhosis and liver problems due to other causes such as a blockage, viral hepatitis, or alcoholic cirrhosis.
Bile
Bile is a fluid that is made and released by the liver and stored in the gallbladder. Bile helps with digestion. It breaks down fats into fatty acid...
Hepatitis
Hepatitis is swelling and inflammation of the liver.
Normal Results
Normally, there are no antibodies present.
What Abnormal Results Mean
This test is important for diagnosing PBC. Almost all people with the condition will test positive. It is rare that a person without the condition will have a positive result. However, some people with a positive test for AMA and no other sign of liver disease may progress to PBC over time.
Rarely, abnormal results may also be found that are due to other kinds of liver disease and some autoimmune diseases.
Risks
Risks for having blood drawn are slight, but can include:
- Excessive bleeding
- Fainting or feeling lightheaded
- Hematoma (blood accumulating under the skin)
- Infection (a slight risk any time the skin is broken)
References
Daniels L, Khalili M, Goldstein E, Bluth MH, Bowne W, Pincus MR. Evaluation of liver function. In: McPherson RA, Pincus MR, eds. Henry's Clinical Diagnosis and Management by Laboratory Methods. 24th ed. Philadelphia, PA: Elsevier; 2022:chap 22.
Eaton JE, Lindor KD. Primary biliary cholangitis. In: Feldman M, Friedman LS, Brandt LJ, eds. Sleisenger and Fordtran's Gastrointestinal and Liver Disease. 11th ed. Philadelphia, PA: Elsevier; 2021:chap 91.
Kakar S. Primary biliary cholangitis. In: Saxena R, ed. Practical Hepatic Pathology: A Diagnostic Approach. 2nd ed. Philadelphia, PA: Elsevier; 2018:chap 26.
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Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
-
Blood test - illustration
Blood is drawn from a vein (venipuncture), usually from the inside of the elbow or the back of the hand. A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. Preparation may vary depending on the specific test.
Blood test
illustration
Review Date: 1/25/2023
Reviewed By: Neil J. Gonter, MD, Assistant Professor of Medicine, Columbia University, NY and private practice specializing in Rheumatology at Rheumatology Associates of North Jersey, Teaneck, NJ. Review provided by VeriMed Healthcare Network. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.
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