SUMMARY. Accurate measurement of pyruvate is particularly important in the detection of mitochondrial enzyme disorders. We describe a simple highperformance liquid chromatography assay for pyruvate with derivatization and fluorescence detection. Between-run variation is below 4·5% and the method is linear between 1 and 1200Ilmol/L. The mean recovery is 10I%. After sample pretreatment, the calculated pyruvate concentration proved to be stable for 15 days when samples were kept at -20°C.

SUMMARY. Accurate measurement of pyruvate is particularly important in the detection of mitochondrial enzyme disorders. We describe a simple highperformance liquid chromatography assay for pyruvate with derivatization and fluorescence detection. Between-run variation is below 4·5% and the method is linear between 1 and 1200Ilmol/L. The mean recovery is 10I%. After sample pretreatment, the calculated pyruvate concentration proved to be stable for 15 days when samples were kept at -20°C.