Age-related reference values for plasma amino acids in a Spanish population measured by gas chromatography-mass spectrometry.

OBJECTIVES: Reference ranges of blood plasma amino acids are required for the diagnosis and management of inherited metabolic disorders affecting one or more amino acids and can significantly impact the clinical decision-making and the quality of patient care. Our objective was to establish the reference values for plasma amino acids in a Spanish population measured by gas chromatography-mass spectrometry (GC-MS). METHODS: Amino acids were extracted, derivatized to N(O)-tert-butyldimethylsilyl, and analyzed by GC-MS. RESULTS: Significant differences in the concentrations of several amino acids have been determined between age groups. Such differences might be due to a combination of several factors, including age, genetic factors, nutritional status, and dietary habits. CONCLUSIONS: The amino acid values are not evidently affected by sex, but they do vary with age. Such data help to provide a basis for diagnosing metabolic abnormalities. To our knowledge, this is the first published article showing the age-related reference ranges for plasma amino acids analyzed by GC-MS.