This test is performed to assess amino acid levels in the urine. It is common for some of each amino acid to be in the urine, but elevated levels of individual amino acids indicates a possible inborn enzyme deficiency with accumulation of a particular amino acid metabolized by the enzyme.
While this test shows increased levels of amino acids in the urine, a 24-hour quantitative urine chromatography is necessary to accurately measure the elevated levels of the specific amino acids.
The increased levels also show up in the plasma (see plasma amino acids). If the test is performed early enough on infants and the defect is treated, the severe mental retardation that can result may be prevented.
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