Liver Kidney Microsomal Antibody

Does this test have other names?

Antibodies to liver and kidney microsomes, anti-LKM

What is this test?

This test looks for a certain type of antibody in your child's blood. Having this antibody – called liver kidney microsomal antibody – may mean that your child has liver damage caused by a form of hepatitis.

Hepatitis means a condition in which your liver is inflamed. Some types of hepatitis are caused by the hepatitis viruses, but this test checks for antibodies to a type of autoimmune hepatitis. If you have autoimmune hepatitis, your immune system attacks your liver.

Autoimmune hepatitis can be either type 1 or type 2. Type 1 can affect anyone but is most common in young women. About half of people with type 1 autoimmune hepatitis have another autoimmune disease, such as type 1 diabetes or ulcerative colitis. Adults can develop type 2 autoimmune hepatitis, but it's most common in girls ages 2 to 14.

People with type 2 autoimmune hepatitis make liver kidney microsomal antibodies, which are different from the antibodies found in type 1 disease.

Why does my child need this test?

Your child may need this test if your child's doctor suspects that she has autoimmune hepatitis or wants to rule out other liver or metabolic conditions. Signs and symptoms of autoimmune hepatitis include:

• Jaundice, or yellowish skin and eyes

• Enlarged liver

• Itching, sometimes over the whole body

• Skin rashes

• Lack of appetite

• Nausea and/or vomiting

• Joint pain

• Abdominal pain or discomfort

• Broken blood vessels on the skin, often in a "spider" shape

• Dark urine

• Pale stools

• Tiredness

Signs of advanced autoimmune hepatitis are:

• Fluid in the abdomen

• Mental confusion

Your child may also have this test to rule out diseases that resemble an autoimmune liver disease.

What other tests might my child have along with this test?

Your child's doctor may also order a group of tests known as a liver panel to help see how well your child's liver is working and look for possible damage and inflammation. He or she may also order other tests for autoantibodies and a liver biopsy, which involves taking a tiny sample of your child's liver to study.

What do my child's test results mean?

Many things may affect your child's lab test results. These include the method each lab uses to do the test. Even if your child's test results are different from the normal value, he or she may not have a problem. To learn what the results mean for your child, talk with your child's health care provider.

Normal results are negative, meaning that no antibodies were found. It's unlikely that your child has type 2 autoimmune liver disease. But your child may still be positive for other antibodies seen with type 2 autoimmune liver disease. Your child's doctor will likely order further testing of these antibodies.

If your child's results are positive, it means that antibodies were found and that your child may have autoimmune liver disease.

How is this test done?

The test requires a blood sample, which is drawn through a needle from a vein in your child's 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 child's arm, he or she may feel a slight stinging sensation or pain. Afterward, the site may be slightly sore.

What might affect my child's test results?

Other factors aren't likely to affect your child's results.

How do I get my child ready for this test?

Your child doesn't need to prepare for this test.