OPTIMAL HANDLING OF BLOOD-SAMPLES FOR ROUTINE MEASUREMENT OF LACTATE AND PYRUVATE

Blood lactate and pyruvate are of critical importance for the diagnosi s of mitochondrial diseases. To determine guidelines for adequate bloo d pyruvate and lactate determinations, intraindividual studies were ca rried out on 10 subjects, and the influences of venostasis, delay befo re deproteinization, and pH in the pyruvate assay were analyzed. Delay s of 1 hour or more before deproteinization of samples induced major e levations of lacate-pyruvate ratios. The lactate-pyruvate ratio correl ated positively with pH in the pyruvate assay, and inadequate pH appea red as a largely underestimated cause of misleading results, while ven ostasis was a minor source of errors.