No special preparations are necessary. Make sure your doctor knows about all the medicines you or your child are taking or have recently used. If this test is being done on an infant who is breast-feeding, make sure the health care provider knows what medicines the nursing mother is taking.
How the Test Will Feel
The test involves only normal urination.
Why the Test is Performed
This test is done to measure amino acid levels in the urine. There are many different types of amino acids. It is common for some of each kind to be found in the urine, but increased levels of individual amino acids can be a sign of an inborn error of metabolism.
The specific value is measured in micromoles per deciliter (micromol/dL).
Failure to have the urine sample promptly evaluated in the laboratory alters the results of the test.
This test is ineffective if the baby is under 6 weeks old and has not been fed dietary protein in the last 48 hours.
Urine chromatography is necessary to accurately measure increased levels of specific amino acids.
Screening infants for increased levels of amino acids can lead to early diagnosis of an inborn error of metabolism. If the condition is promptly treated, complications such as severe mental retardation may be prevented.
Frank A. Greco, M.D., Ph.D., Director, Biophysical Laboratory, The Lahey Clinic, Burlington, MA. Review provided by VeriMed Healthcare Network. Also reviewed by David Zieve, MD, MHA, Medical Director, A.D.A.M., Inc.