Alkaline Phosphatase (ALP): About Your Child's Test

What is it?

An alkaline phosphatase (ALP) test measures the amount of the enzyme ALP in your child's blood. ALP is made mostly in the liver and in bone. But some of it is made in the intestines and kidneys.

Why is this test done?

The ALP test is done to:

• Check for liver damage when you're taking medicines that can damage the liver.
• Help look for liver disease. Liver disease may cause symptoms. These may include pain in the upper belly, nausea, vomiting, and sometimes jaundice.
• Check for bone problems (sometimes found on X-rays). Some examples are rickets, osteomalacia, bone tumors, and Paget's disease. The test can also check for too much parathyroid hormone. This is the hormone that controls bone growth.
• Check to see how well treatment for Paget's disease or a vitamin D deficiency is working.

How do you prepare for the test?

In general, you don't need to do anything before your child has this test. Your doctor may give you some specific instructions.

How is the test done?

A health professional uses a needle to take a blood sample, usually from the arm.

How long does the test take?

The test will take a few minutes.