Effect of storage on measured blood lactate concentration. A research note.

It is not always convenient to analyse blood samples immediately after collection. The purpose of this study was to evaluate the effect of storage for 2 to 6 weeks on lactate concentration in whole blood samples. Following 219 outdoor running races, fingertip blood samples were obtained and immediately treated with an anticoagulant (EDTA), an erythrocyte-lysing agent (Triton X-100), and an anti-glycolytic agent (sodium fluoride). Samples were analysed shortly after they were obtained and then again after either 2 weeks (n = 73), 4 weeks (n = 73), or 6 weeks (n = 73). Results of ANOVAs revealed an effect of storage time on the measured concentration (F2,216 = 16.26, p < 0.01). There was no effect of storage for 2 or 4 weeks but, after 6 weeks, mean (+/- SD) blood lactate concentration values were 0.8 +/- 1.1 mM (+5%) higher than initially (t72 = 6.77, p < 0.01). It is concluded that blood samples treated with Triton X-100, EDTA, and sodium fluoride may be stored up to 4 weeks without appreciable effect on measured blood lactate concentration.