A comparison of methodologies for measuring glucose concentrations in the horse

Abstract

<h2>ABSTRACT</h2> Five methods of measuring glucose in the horse were compared with plasma glucose reference values generated with an Autoanalyzer3 (Seal Analytical Ltd., Hampshire, UK). Plasma glucose was measured with a One Touch Ultra (LifeScan, Milpitas, CA) hand-held glucose meter and a YSI 2300 Stat Plus Glucose and Lactate Analyzer (YSI; YSI Inc., Yellow Springs, OH). Glucose also was measured in whole blood using One Touch Ultra and YSI. Finally, interstitial glucose measurements were obtained with a SEVEN continuous glucose monitoring device (Dexcom, San Diego, CA). Glucose measurements were obtained on 2 consecutive days in 6 American Quarter Horses maintained on native prairie hay and water. Each morning, 2 baseline glucose measurements were obtained 30 min apart. After a meal of sweet feed, glucose measurements were obtained every 30 min for 4 h. Patterns of postprandial glucose increases and subsequent decreases were similar across all methods but were displaced vertically from one another. Of the 5 methods, the YSI method with plasma appeared to have the best reproducibility of Autoanalyzer3 glucose values based on a random coefficients model with intercept not statistically different from zero (P = 0.08) and slope not statistically different from one (P = 0.08) and by having the highest Lin's concordance coefficient (r = 0.77). The other methods had biased random coefficients models with intercepts not equal to zero (P > 0.05) and slopes not equal to one (P > 0.05) and Lin's concordance coefficient values that ranged from 0.39 to 0.64. Technical difficulties with the SEVEN device limited its utility as a reliable method for evaluating glucose in the equine.