Amino Acid Analysis
Amino Acid analysis is necessary for the diagnosis of a variety of inborn errors of metabolism. These include, but are not limited to:
- phenylketonuria
- tyrosinemia
- citrullinemia
- non-ketotic hyperglycinemia
- maple syrup urine disease
- and homocystinuria.
The assay is also key for the continued monitoring of treatment plans for these disorders and useful for assessing nutritional status of patients.
Interpretive Information:
Elevation of 1 or more amino acids may be diagnostic of an aminoacidopathy. Elevated amino acid levels are also associated with noninherited diseases such as severe liver disease and renal tubular disorders (eg, Fanconi syndrome).
Decreased levels of amino acids are associated with malnutrition as seen in the elderly or those with poor protein intake or gastrointestinal disease.
Additional laboratory testing is required to diagnose other inherited disorders (ie, lactic acidosis, organic aciduria, and some urea cycle defects). Results should be evaluated in the context of clinical findings and/or additional test results.
Infant formulas that are supplemented with amino acids (particularly methionine and homocitrulline) and parenteral nutrition may affect the clinical accuracy of this test. Bacterial contamination of specimens and certain medications, such as valproic acid, can also affect the levels of specific amino acids. In addition, the absence of a protein-containing diet in newborns may preclude detection of selected aminoacidopathies.
References:
Part 8. Amino Acids. In: Scriver CR, Beaudet AL, Valle D, Sly WS, Childs B, Kinzler KW, Vogelstein B, eds. The Metabolic and Molecular Bases of Inherited Disease. 8th ed. New York, NY: McGraw-Hill, Inc; 2001;1665-2105.
Part IV. Disorders of amino acid metabolism and transport. Fernandes J, Saudubray J-M, Van den Berghe G, eds. Inborn Metabolic Diseases Diagnosis and Treatment. 3rd ed. New York, NY: Springer; 2000;169-273.
Part 2. Disorders of amino acid metabolism. Nyhan WL, Barshop BA, Ozand PT, eds. Atlas of Metabolic Diseases. 2nd ed. New York, NY: Oxford University Press Inc; 2005;109-189.
Blau N, Duran M, Blaskovics ME, Gibson KM, eds. Physician's Guide to the Laboratory Diagnosis of Metabolic Diseases. 2nd ed. New York, NY: Springer; 2003.
Heiblim DI, Evans HE, Glass L, et al. Child neurology: amino acid concentrations in cerebrospinal fluid. Arch Neurol. 1978;35:765-768.
Goldsmith RF, Earl JW, Cunningham AM. Determination of delta-aminobutyric acid and other amino acids in cerebrospinal fluid of pediatric patients by reversed-phase liquid chromatography. Clin Chem. 1987;33:1736-1740.
Biomarkers in this category
35 biomarkers · optimal ranges shown
Nonessential Protein Amino Acids
An intermediary metabolite of lysine and tryptophan.
also known as Alpha-amino-N-butyric acid (A-ANB)
Amino Acid
Nonessential Protein Amino Acid
Nonessential Protein Amino Acids
B-Vitamin Markers
Dietary Peptide Related Markers
Urea Cycle Markers
B-Vitamin Markers
Glycine/Serine Metabolites
Nonessential Protein Amino Acids
Nonessential Protein Amino Acids
Amino acid with important functions within the body.
Amino Acid
Hydroxyproline is a collagen related amino acid.
Branched Chain Amino Acids
Branched Chain Amino Acids
Amino Acid
Amino Acid
Urea Cycle Markers
Amino Acid
Nonessential Protein Amino Acids
an amino acid
Glycine/Serine Metabolites
Amino Acid
Amino Acid
Amino Acid
Nonessential Protein Amino Acids
Branched Chain Amino Acids