Comparison of a manual and an automated enzymatic technique for determining blood lactate concentrations.

Although analysis of lactate concentrations with a Yellow Springs Instruments (YSI) automated analyzer has become very popular in Sports Medicine, the accuracy and reliability of this technique has not been carefully studied. Additionally, the influence of a common lysing agent Triton X-100 (TX) on blood lactate measurements has not been determined. Blood was collected from each of ten subjects at rest and 2, 6, 10, 14 and 20 minutes following maximal exercise (60 samples). Lactate concentration was measured by the YSI and Boehringer Mannheim (BMM) techniques. Two YSI 23L analyzers were supplied with buffer with TX (YSITX), and two without (YSINON) to permit comparisons of lysed and unlysed whole blood lactate levels over the physiological range. MANOVA analysis revealed a statistical difference (p less than .05) between duplicates only for one machine, and duplicates of that machine differed by less than 3%. Mean measurements between similarly prepared machines differed significantly for the NONTX machines, but only by less than 3%. Differences were significant between BMM and YSINON, but not between BMM and YSITX. Regression analysis indicated close agreement between BMM and YSITX (R2 = .99). There was a tendency for a large discrepancy between methods at resting concentrations.