Antibodies to liver and kidney microsomes, anti-LKM

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

Hepatitis is a condition in which the liver is inflamed. Some types of hepatitis are caused by a hepatitis virus. But this test checks for antibodies to a type of autoimmune hepatitis. If your child has autoimmune hepatitis, their immune system attacks the 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 type 2 is most common in girls ages 2 to 14.

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

Your child may need this test if the doctor thinks that they have autoimmune hepatitis. Or your child may need the test to check for other liver or metabolic conditions. Signs and symptoms of autoimmune hepatitis include:

• Yellowish skin and eyes (jaundice)
• Enlarged liver
• Itching, sometimes over the whole body
• Skin rashes
• Lack of appetite
• Nausea, vomiting, or both
• Joint pain
• Belly (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 (belly)
• Mental confusion

Your child may also have this test to check for diseases that are like an autoimmune liver disease.

Your child may also need a group of tests known as a liver panel. These tests help check how well your child's liver is working. They check for liver damage and inflammation. They may also need other tests for autoantibodies. And your child may need a liver biopsy. This is done by taking a tiny sample of your child's liver to check in a lab.

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, they may not have a problem. To learn what the results mean for your child, talk with your child's doctor.

Negative results mean that no antibodies were found and 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. More testing for these antibodies may be needed.

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

The test is done with a blood sample. A needle is used to draw blood from a vein in your child's arm or hand.

Having a blood test with a needle carries some risks. These include bleeding, infection, bruising, and feeling lightheaded. When the needle pricks your child's arm or hand, they may feel a slight sting or pain. Afterward, the site may be sore.

A history of chronic hepatitis C may lead to a positive result.

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