Validation and comparison of two methods of measuring lactate in equine plasma
Article first published online: 8 NOV 2010
© 2010 EVJ Ltd
Equine Veterinary Journal
Special Issue: Proceedings of the 8th International Conference on Equine Exercise Physiology
Volume 42, Issue Supplement s38, pages 155–160, November 2010
How to Cite
BUTUDOM, P., FOREMAN, J. H., KLINE, K. H. and WHITTEM, E. L. (2010), Validation and comparison of two methods of measuring lactate in equine plasma. Equine Veterinary Journal, 42: 155–160. doi: 10.1111/j.2042-3306.2010.00219.x
- Issue published online: 8 NOV 2010
- Article first published online: 8 NOV 2010
- [Paper received for publication 08.01.10; Accepted 21.06.10]
- lactate analysers
Reasons for performing study: Some methods of lactate (LA) measurement have not been validated appropriately for use in horses.
Objectives: To validate 2 LA analysers (YSI 2300 Stat Plus and TDx Lactic Acid Assay) for use with equine plasma and to compare plasma [LA] determined by the 2 methods.
Methods: Both instruments were evaluated for linearity, parallelism, recovery and precision using serial dilutions of standard LA solutions and equine plasma and then comparing results with linear regression or paired t tests. Plasma [LA] results were compared in 275 blood samples collected from horses exercising at various intensities using Bland-Altman analysis. Level of significance was P<0.05.
YSI exhibited good linearity for both LA standards and equine plasma (P<0.05) at 0–30 mmol/l. TDx had good linearity at 0–12 mmol/l (P<0.05); with LA standard solutions >12 mmol/l and with equine plasma, linearity was decreased. YSI exhibited good parallelism between LA standards and equine plasma LA measurements throughout the 0–30 mmol/l range (P>0.05). Parallelism was poor with TDx (P<0.05). Mean ± s.d. % recovery was 101.7 ± 3.4% for YSI (acceptable) and 110.6 ± 8.4% for TDx (unacceptable). Within-run and mean between-run coefficients of variation (CV) for plasma samples tested from 3.3–29.5 mmol/l were 0.4–3.0% for YSI. CVs for samples tested from 2.8–8.0 mmol/l were 17.4–24.1% for TDx. In 275 plasma samples, [LA] ranged from 0.1–42.7 mmol/l and 0.3–50.6 mmol/l for the YSI and TDx methods, respectively. The difference in plasma [LA] determined by the 2 methods was −1.0 ± 3.2 mmol/l, documenting that the TDx overestimated the YSI results by a mean value of 1 mmol/l.
Conclusions: It was concluded that the YSI method was a reliable method for measuring equine plasma [LA] from 0–30 mmol/l. The TDx method was found not to be suitable for use with equine plasma due to greater variability in measurements (high CV).