Gas Chromatography in Diagnostic Biochemistry of Abnormal Valine Metabolism

Amino acids in biological fluids can be rapidly and accurately quantitated by gas chromatography. Mod-ification of existing gas-chromatographic techniques allow as little as 25 tl of biological fluids to be ana-lyzed, compatible with sample sizes easily obtained in pediatric studies. Simplified diagnostic biochemi-cal evaluation of a suspected aminoaciduria can be begun at birth, or shortly after. Normal amino acid patterns are compared with those found in a patient with abnormal amino acid concentrations. Gas chro-matographic evidence is presented as a diagnostic aid in the evaluation of a patient with abnormal va-line metabolism. AdditIonal Keyphrases: pediatric specimens #{149}cation-exchange chromatography #{149}normal values for infants gas chromatography of amino acids in plasma, urine, CSF Quantitation of amino acids in plasma, urine, and (or) cerebrospinal fluid of pediatric patients with clinical manifestations of inborn metabolic errors is an indispensable diagnostic tool (1, 2). Analysis by amino acid analyzer takes too long. Greater knowledge of amino acid metabolism as related to clinical disease is accompanied by the need for faster analysis and for quantitation of the amino acid con-tent of human biological fluids (3). High-voltage paper electrophoresis is used routinely in this labora-tory for qualitative screening; it is rapid and inex-pensive, but reliable quantitation with this tech-nique is impossible. The versatility of GC1 is attractive when consid-ering multiphasic metabolic evaluations. If GC is adapted for amino acid analysis, it potentially can also be used for a variety of analyses of other organi