Validation of a semi-automated technique for measuring lactate in whole blood

An electrode-based lactate analyzer was recently developed to facilitate "stat" laboratory measurement of lactate in whole blood. The results obtained with this technique were compared with those of our continuous-flow enzymatic method for 172 analyses of samples from 25 pigs; 88 analyses of samples from 12 normal human volunteers before, during, and after exercise; and 91 analyses of samples from 80 critically ill patients. This comparison revealed strongly significant linear correlations: r = 0.992 for the porcine analyses and r = 0.994 for the combined human analyses. In analytical-recovery studies with pooled porcine plasma with an initial lactate concentration of 3.85 mmol/L, 94.3% of added lactate (1, 5, and 10 mmol/L) was accounted for in the electrode technique, 96% in the reference technique. We conclude that the electrode-based lactate analyzer is rapid, precise, and accurate for measurement of lactate in whole-blood samples.