A comparison of a portable blood lactate analyser and laboratory plasma analysis of blood samples from exercised horses

Quick, simple methods for blood lactate analysis could be helpful in evaluating xercise response in the field, but methods validated for analysis of blood collected after high intensity exercise in horses are scarce. The aim of the present study was to compare the results obtained using a commercial, portable blood lactate analyser with those from laboratory plasma analysis of blood samples from horses performing intensive exercise. Venous blood samples were collected from 220 horses within 5 min of performing exercise at a mean peak heart rate of 222 ±9 beats/min. The samples were kept chilled and analysed using portable analyser within 10 min of collection. Samples were also centrifuged and the plasma frozen (-20 °C) until analysed using an enzymatic and spectrophotometric laboratory lactate analysis. There was a significant ( P <0.05) correlation (R=0.94) between the methods at portable analyser values <12.0 mmol/l, but at higher values there was no correlation. There was a significant effect of method ( P <0.0001) and portable analyser values were 21% lower than plasma lactate concentrations in the range 2.0-12.0 mmol/l. It is concluded that the portable analysis correlated well to a laboratory plasma analysis at portable analyser values <12.0 mmol/l and that the portable analyser appears to be a safe method for lactate analysis during training conditions, when very high lactate concentrations are not expected. However, users should be aware that the results underestimate the corresponding plasma values by approximately 20%.