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Alkaline Phosphatase Test

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KEY POINTS

  • This test measures an enzyme called alkaline phosphatase (ALP) in your child’s blood. Enzymes are chemicals that help the cells of your child’s body work. The amount of ALP in your child’s blood is measured to help diagnose liver and bone disease, or to see how well treatment is working.
  • A small amount of blood is taken from a vein in your child’s arm with a needle. In younger children, this test can be done with a finger prick or heel stick. The blood is collected in tubes and sent to a lab.
  • Talk to your child’s healthcare provider about what the test results mean and ask any questions you have.

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What is the alkaline phosphatase test?

This test measures an enzyme called alkaline phosphatase (ALP) in your child’s blood. Enzymes are chemicals that help the cells of your child’s body work. ALP is an enzyme found in most tissues, especially in the liver and bones.

Why is this test done?

The amount of ALP in your child’s blood is measured to help diagnose liver and bone disease. The test may also be used to help check medical treatments that can damage the liver or bones.

How do I prepare my child for this test?

  • Your child may need to avoid taking certain medicines before the test because they might affect the test result. Tell your child's healthcare provider about all the medicines and supplements your child takes. Don't stop any of your child’s regular medicines without first consulting with your child’s healthcare provider.
  • Talk to your child’s healthcare provider if you have any questions about the test.

How is the test done?

Having this test will take just a few minutes. A small amount of blood is taken from a vein in your child’s arm with a needle. In younger children, this test can be done with a finger prick or heel stick. The blood is collected in tubes and sent to a lab.

Ask your child’s healthcare provider how and when you will get your child’s test results.

What does the test result mean?

Some of the reasons your child’s ALP may be higher than normal are:

  • Your child has a liver infection such as viral hepatitis
  • Your child has a blockage in the liver or gallbladder caused by gallstones or a tumor
  • Your child’s liver is inflamed because of certain medicines your child takes
  • Your child has kidney disease
  • Your child’s body needs more vitamin D
  • Your child has liver cancer
  • Your child has bone cancer or another bone disease

ALP levels in children and teens may also be higher than normal due to normal bone growth.

Your child’s ALP may be lower than normal if:

  • Your child’s body is not getting the nutrients it needs from food.
  • Your child has anemia.

What if my child’s test result is not normal?

Test results are only one part of a larger picture that takes into account your child’s medical history, physical exam, and current health. Sometimes a test needs to be repeated to check the first result. Talk to your child’s healthcare provider about the results and ask questions such as:

  • If your child needs more tests
  • What kind of treatment your child might need
  • What lifestyle, diet, or other changes your child might need to make
Developed by Change Healthcare.
Pediatric Advisor 2022.2 published by Change Healthcare.
Last modified: 2022-01-03
Last reviewed: 2017-06-26
This content is reviewed periodically and is subject to change as new health information becomes available. The information is intended to inform and educate and is not a replacement for medical evaluation, advice, diagnosis or treatment by a healthcare professional.
© 2022 Change Healthcare LLC and/or one of its subsidiaries
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