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Antimitochondrial antibody How the Test is Performed:
Adult or child:
Blood is drawn from a vein ( venipuncture ), usually from the inside of the elbow or the back of the hand. The puncture site is cleaned with antiseptic, and a tourniquet (an elastic band) or blood pressure cuff is placed around the upper arm to apply pressure and restrict blood flow through the vein. This causes veins below the tourniquet to distend (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 tourniquet 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 .
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.
How to Prepare:
Fasting may be required for up to 6 hours before the test (usually overnight).
Infants and children:
The physical and psychological preparation you can provide for this or any test or procedure depends on your child's age, interests, previous experience, and level of trust. For specific information regarding how you can prepare your child, see the following topics as they correspond to your child's age:
How it Feels:
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 .
Risks:
- excessive bleeding
- fainting or feeling lightheaded
- hematoma (blood accumulating under the skin)
- infection (a slight risk any time the skin is broken)
- multiple punctures to locate veins
Why this Test is Performed:
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.
Positive antimitochondrial antibody tests result in up to 94% of people with biliary cirrhosis , and 25% of those with chronic active hepatic (liver) or idiopathic cirrhosis (compared to less than 1% of normal people). Titers of more than 1:160 are generally found only in biliary cirrhosis. Antimitochondrial antibodies are helpful in distinguishing biliary ( bile system) cirrhosis from extrahepatic obstruction (obstruction outside of the liver), viral hepatitis , and alcoholic cirrhosis.
Normal Values:
No presence of antibodies is normal.
Abnormal Results:
A positive test may indicate:
Cost:
The estimated cost is $40.
Special Considerations:
Antimitochondrial antibodies are not species or organ specific. The antigen that triggers antibody production appears to be a lipoprotein component on the inner mitochondrial membrane (the mitochondria are very small bodies within cells).
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.
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