COUPLED ENZYMATIC METHOD TO MEASURE BLOOD LACTATE BY AMPEROMETRIC MONITORING OF THE RATE OF OXYGEN DEPLETION WITH A CLARK OXYGEN-ELECTRODE

A rapid, sensitive and reliable method to measure lactate in human blood is described. The method is based on the enzymatic oxidation of lactate to pyruvate in the presence of NAD+ and lactate dehydrogenase (LDH). The reaction product, NADH, is then oxidized by molecular oxygen and carried in the buffered reagent medium in the presence of horseradish peroxidase and other cofactors. The maximum rate of O2 depletion, directly proportional to the amount of lactate ion present in the sample, is amperometrically monitored by a membrane O2 electrode. No sample pretreatment is required in this procedure other than dilution. A comparison study between the described method and a spectrophotometric method shows good correlation.