Lifespan's A - Z Health Information Library

This is a blood test that detects the presence of antibodies against mitochondria (a part of cells).

Blood is drawn from a vein, usually on the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and an elastic band is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the band to fill with blood.

A needle is inserted into the vein, and the blood is collected in an air-tight vial or a syringe. During the procedure, the band is removed to restore circulation. Once the blood has been collected, the needle is removed, and the puncture site is covered to stop any bleeding.

For an infant or young child:

The area is cleansed with antiseptic and punctured with a sharp needle or a lancet. The blood may be collected in a pipette (small glass tube), on a slide, onto a test strip, or into a small container. Cotton or a bandage may be applied to the puncture site if there is any continued bleeding.

Fasting may be required for up to 6 hours before the test (usually overnight).

For infants and children:

The preparation you can provide for this test depends on your child's age, previous experiences, and level of trust. For specific information regarding how you can prepare your child, see the following topics:

• Infant test or procedure preparation (birth to 1 year)
• Toddler test or procedure preparation (1 to 3 years)
• Preschooler test or procedure preparation (3 to 6 years)
• Schoolage test or procedure preparation (6 to 12 years)
• Adolescent test or procedure preparation (12 to 18 years)

When the needle is inserted to draw blood, some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

This test is primarily used when there are symptoms of liver or other organ damage, to confirm a medical diagnosis, or help to identify possible causes of tissue damage.

The antimitochondrial antibody test is positive in up to 94% of people with primary biliary cirrhosis, and in 25% of those with chronic, active hepatic or iodopathic (of unknown cause) cirrhosis. It is positive in less than 1% of people who do not have these conditions. Titers (blood levels) of more than 1:160 are generally found only in primary biliary cirrhosis.

Antimitochondrial antibodies are helpful in distinguishing biliary (bile system) cirrhosis from liver problems due to obstruction outside of the liver, viral hepatitis, and alcoholic cirrhosis.

Normally, there are no antibodies present.

A positive test may indicate:

• Autoimmune hepatitis
• Cirrhosis
• Liver obstruction
• Primary biliary cirrhosis
• Theumatoid arthritis
• Dystemic lupus erythematosus
• Thyroiditis

• Excessive bleeding
• Fainting or feeling light-headed
• Hematoma (blood accumulating under the skin)
• Infection (a slight risk any time the skin is broken)
• Multiple punctures to locate veins

Antimitochondrial antibodies are not organ specific. Mitochondria are very small structures within cells. The antigen that triggers antibody production appears to be a protein found inside mitochondria.

Veins and arteries vary in size from one patient to another and from one side of the body to the other. Obtaining a blood sample from some people may be more difficult than from others.