ELECTROCHEMICAL ASSAY SYSTEM WITH SINGLE-USE ELECTRODE STRIP FOR MEASURING LACTATE IN WHOLE-BLOOD

We have developed an assay system for measuring lactate in whole blood , consisting of a single-use strip of an enzyme-coated electrode and a small meter. The electrode strip is made of three plastic films: a co ver sheet, a spacer, and an insulation layer printed with electrodes t hat are coated with lactate oxidase (EC 1.1.3.x) and ferricyanide as a n electron mediator. The meter measures the magnitude of the anodic cu rrent of the reduced mediator by the enzymatic reaction and displays t he lactate concentration 60 s after a blood sample (5 muL) is applied. The calibration curve was linear up to 20 mmol/L, and the between-run CVs at three concentrations were 1.7-8.4%. Lactate concentrations det ermined by this method (y) in blood samples from healthy individuals b efore and after exercise agreed with the results obtained by the conve ntional enzymatic method (x): y = 0.97x - 0.3, S(y\x) = 0.7. This assa y provides a rapid and convenient test for measuring blood lactate con centrations.