A urine amino acid test measures the level of amino acids in the urine. Amino acids are the building blocks that combine to form proteins.

Who is a candidate for the test?

A urine amino acid test is ordered when the healthcare provider suspects an inborn error of metabolism. Inborn errors of metabolism are genetic conditions in which the person lacks a particular enzyme. Enzymes are substances that allow a person to use protein for various body functions. When an enzyme is missing, the person is unable to use a particular protein appropriately. The amino acids that make up the protein then build up in the body. Some of the amino acids are excreted in the urine. There are over 20 different amino acids. Each disorder can affect the level of various amino acids in the urine.

A urine amino acid test is generally performed on infants and young children to help diagnose the disorder. It may also be done to monitor persons with known amino acid disorders.

How is the test performed?

To perform this test, a urine sample is needed. A person is asked to supply urine in a special container. Advice on how to get a urine sample from an infant is provided if necessary. The urine sample is taken to a lab for testing.