Development and analytical validation according COFRAC recommendations of pyruvate and ketone body assay on open automated analyser]

Measurements of pyruvate and ketones bodies (acetoacetate and 3-hydroxybutyrate) are essential to the investigation of intermediary metabolism. Indeed, their blood levels reflect energy balance influenced by nutritional status. This balance can be disturbed in certain diseases such as diabetes and some inherited metabolic disorders. We have developed methods for assays on open automated biochemistry analyser, Konelab 20 XT (ThermoFischer, Whaltham USA), using kits marketed by Sobioda (Montbonnot, France) for pyruvate and Wako Chemicals GmbH (Neuss, Germany) for ketones, on deproteinised blood sample. We have validated the performance of these three quantitative methods using NF EN ISO 15189 (range B) standard criteria. We obtain satisfactory results concerning fidelity (precision measured as within and between batch CVs are respectively less than 7% and less than 6%), measuring ranges (from 7.7 to 228 mu mol/L for pyruvate and from 22.6 to 650 mu M for total ketone bodies), accuracy (10.4 mu mol/L in physiological range for pyruvate and 7.1 mu mol/L for 3-hydroxybutyrate) and comparing methods (versus manual assay with spectrophotometry on Uvikon XL). Establishment of reference ranges (35 to 74 mu mol/L for pyruvate, less than 100 mu M for 3-hydroxybutyrate and less than 44 mu mol/L for acetoacetate) and reagents stability study (up to 12 week's if frozen) have enabled us to finalize method validation and to add these assays to our routine laboratory repertoire.