Test-strip method for measuring lactate in whole blood.

We have developed a dry reagent strip system for measuring lactate in whole blood. The test strip contains lactate oxidase (no EC number assigned), horseradish peroxidase (EC 1.11.1.7), and N-ethyl-N-(2-hydroxy-3-sulfopropyl)-m-toluidine. The system is designed to measure with a reflectometer the color that developed in the test strip, although the lactate concentration can be estimated without the reflectometer. The between-run coefficients of variation for controls at three concentrations were 2.9-5.3%. The lactate concentrations in blood samples from healthy subjects before and after exercise correlated well (r = 0.97) with the results measured by the comparison method with the use of lactate oxidase. This dry reagent strip system provides a convenient and rapid test for measuring blood lactate in clinical and sports medicine.