Validation of the handheld Lactate-Pro analyzer for measurement of blood L-lactate concentration in cattle.

Abstract

Blood L-lactate concentration (LAC) can be used for various diagnostic purposes in cattle. As multiple handheld analyzers for LAC exist, it is important to validate their use in cattle in comparison with reference laboratory blood analyzers. The objectives of this study were to validate the handheld Lactate Pro meter (LacP) including reproducibility, and compare the measurements with the StatProfile (StatP) as a gold standard. In addition, diagnostic sensitivity and specificity, and the impact of HCT on LAC measured by both analyzers were assessed. A cohort of 64 cattle with acute medical and surgical conditions was studied. Whole blood samples in heparin lithium tubes were analyzed upon arrival with both StatP and LacP. Twenty-three samples were immediately retested to assess intra-assay coefficient of variation (CV). The HCT values were also recorded. The LAC using LacP was highly correlated with the StatP (r=0.9736 [95% confidence interval [CI]: 0.9562-0.9841]). The LacP underestimated LAC (mean difference:-0.9mmol/L, 95% CI:-3.1mmol/L to 1.3mmol/L). The intra-assay CV was excellent (4.77%). No significant correlation was observed between LacP or StatP and HCT (P=.39 and .09, respectively). Sensitivity and specificity for LacP were 91.7% (95% CI: 76.4-97.8%) and 100% (83.4-100%, cutoff of 4mmol/L), and 78.6% (58.5-90.9%) and 100% (87.0-100%, cutoff of 6mmol/L). The LacP handheld lactate meter can be used safely and reliably cow-side, although it underestimates LAC value when compared with a standard laboratory analyzer especially for LAC≥10.0mmol/L. The LAC value was not influenced by HCT in this study.