Aminoaciduria is the presence of an abnormal or large amount of amino acids in the urine. Amino acids are the building blocks of proteins. When proteins are broken down or digested, the amino acids are what remain. Aminio acids play many important roles in the human body including being used as a source of enegy and tissue repair. There are usually small amounts of amino acids in normal urine, however increased levels may be a sign of a metabolic disorders, where the body is not processing proteins correctly. These disorders primarily affect the kidneys, liver and brain. Aminoaciduria can be detected by taking a simple urine test. The specific amino acid/s found at abnormal levels in the urine can help determine what the underlying disorder may be. Screening infants for increased levels of amino acids in the urine is important as it can help detect for possible metabolic problems. Early detection in some of these disorders can prevent some future complications.