Examination of four different instruments for measuring the blood lactate concentration

Abstract

ABSTRACT There is incomplete information on the performance of different instruments used to measure the blood lactate concentration. We have therefore examined instruments from Yellow Springs Instruments (YSI 23L and YSI 1500), and three cheaper and simpler instruments: Dr. Lange’s LP8+, Lactate Pro from Arkray, KDK, and Accusport from Boehringer Mannheim. First a number of blood samples were analysed by standard enzymatic photofluorometry (our control method) and in addition by one or more of the instruments given above. Second, measurements done by two or more «identical» instruments were compared. Third, since Lactate Pro and Accusport are small (»100 g, pocket-size) battery-driven instruments that might be used for outdoor testing, the performance of these instruments was examined at simulated altitudes (O2 pressure of <10 kPa) and in addition at temperatures below –20 °C while screening the instruments as much as possible from the cold.

Most of the different instruments showed systematically too high or too low values (10-30 % deviation). In most cases the deviations rose both absolutely and relatively by the blood lactate concentration. The observed differences between instruments may affect the «blood lactate threshold» by 2-5 %. For YSI 1500 instruments we found a systematic difference of >10 % between two «equal» instruments, while no such difference was found for the other instruments. Lactate Pro gave reliable results both at –21 ± 1 °C and at simulated altitude. Accusport gave reliable results in the cold but 1.85 mmol L–1 too high readings at the simulated altitude. We conclude that of the three simple instruments examined the Lactate Pro was at least as good as the YSI instruments and superior to the other two tested.