Determination of free and total carnitine with a random-access chemistry analyzer

Carnitine deficiency presents as a major problem in fatty acid oxidation. The use of a plasma carnitine assay can rapidly help to describe this deficiency. The method we describe here requires two simple steps of sample preparation, followed by automated analysis with the Beckman Synchron CX4 random-access chemistry analyzer. The goal of this method development was to reduce the cost of analysis and to allow a greater number of laboratories to perform this assay on demand within 1 h for both free and total carnitine. The method has a linearity of 0-150 micromol/L and a detection limit of 5 micromol/L. The inter- and intraday CVs are <20%. The method agreed closely with both the widely used RIA and spectrophotometric methods.