Evaluation of three portable lactate-measurement devices in exercising horses

Abstract

Since one of the validated handheld lactate (LA) measurement devices (Lactate Pro) is now out of production, an alternative instrument is to be found for equine exercise testing in the field and for use in horses with gastrointestinal disorders. The aim of this study was to evaluate three handheld LA analysers (Lactate Pro, Lactate Pro-2 and Stat Strip Lactate Xpress), and to compare these with the gold standard laboratory assay (Lab-LA; DXC-600 Analyser - Beckman Coulterlab). A total of 215 blood samples were collected from the jugular vein of 44 eventing horses during standardized exercise testing. Immediately after collection each blood sample was parallel tested using the three lactate analysers. The rest of each blood sample was placed in NaF tubes and centrifuged within 8 hours. The plasma was stored at -20°C for laboratory assay. The results of each analyser were compared with the laboratory analyser. All data were statistically evaluated using a linear mixed effect model (Akaike's Information criterion; t>2.00) and Partial Pearson correlations. The Partial Pearson correlations between Lab-LA and Lactate Pro, Lactate Pro-2 and Stat Strip Lactate X-press were 0.974, 0.981, and 0.828 respectively. Of the three instruments the Lactate Pro-2 provided the closest correlation with the laboratory assay. The predicted values were derived from the formula: Log (Lab-LA) = 0.27175+0.94567∗(Lactate Pro-2) or Lab-LA = 1.3226∗(Lactate Pro-2)0.94567. The predicted value for Lab-LA values using the Lactate Pro-2 was 0.992 for an average horse. The Lactate Pro-2 proved to be a good alternative for the Lactate Pro that is now no longer in production.