Organic acids in the second morning urine in a healthy Swiss paediatric population.

Organic acid analysis is used for the early detection/ exclusion and for the follow-up of inherited disorders of amino acid and organic acid metabolism. Urinary organic acid concentrations in 417 healthy Caucasian children (1 day to 17 years of age) were determined after liquid solid extraction, as their trimethylsilyl derivatives, by gas chromatography and mass spectrometry. Concentrations of most of the organic acids adjusted for creatinine tend to decrease with age.