Renaud D L, Hare K S, Wood K M, Steele M A, Cantor M C
Department of Population Medicine, University of Guelph, Guelph, ON, Canada, N1G 2W1.
Department of Animal Biosciences, University of Guelph, Guelph, ON, Canada N1G 2W1.
JDS Commun. 2022 Apr 26;3(4):301-306. doi: 10.3168/jdsc.2021-0190. eCollection 2022 Jul.
The objective of this cross-sectional, diagnostic accuracy study was to validate a human blood glucose meter (Contour Next One Meter, Ascensia Diabetes Care) for accuracy and precision when measuring blood glucose, and for diagnostic accuracy for hypoglycemic status in dairy calves using whole blood and blood plasma. A total of 49 male dairy calves [body weight (BW): 46.3 ± 0.8 kg] had jugular catheters placed within 75 min after birth. Thereafter, blood was withdrawn from the catheter at specific time points (-10, 10, 20, 30, 45, 60, 90, 120, 180, 240, 360, 480, and 600 min) relative to the first and second colostrum feedings (2 h 15 min and 14 h 5 min postnatal; feeding rate: 7% of BW wt/wt). The reference standard method for plasma glucose concentration was determined colorimetrically and in duplicate using the glucose oxidase-peroxidase reaction. Data were assessed for agreement between the glucose meter and the reference standard using Lin's concordance correlation coefficients (CCC), coefficients of determination (precision), and Bland-Altman plots. In addition, a mixed linear regression model was built using the reference method as the outcome, with the glucose meter and repeated measures of time as the explanatory variables and calf as a random effect. The sensitivity (Se), specificity (Sp), and area under the curve (AUC) for the glucose meter using calf whole-blood and plasma were calculated at a threshold of <4.44 mmol/L to determine hypoglycemia. The precision (CCC = 0.95, R = 0.93) and accuracy (AUC = 0.98) of the glucose meter were very high when used on 1,303 blood plasma samples. Youden's index revealed a threshold of <4.45 mmol/L for the glucose meter when used with plasma, leading to Se of 94.2% and Sp of 91.9%, with 92.5% of samples being correctly classified, suggesting high diagnostic accuracy. When using whole blood, precision (CCC = 0.85 and R = 0.73) and accuracy (AUC = 0.92) were high when used on 476 samples. Youden's index revealed a threshold of <4.95 mmol/L for the glucose meter when used with whole calf blood, leading to Se of 95.6% and Sp of 80.3%, with 84.7% of samples being correctly classified, suggesting high diagnostic accuracy for use on farm. In summary, this glucose meter was validated for measuring calf blood glucose using both plasma and whole blood. This meter can measure glycemic status in calves and may be useful for clinical and on-farm use to make intervention decisions.
这项横断面诊断准确性研究的目的是验证一款人体血糖仪（轮廓下一代血糖仪，拜耳糖尿病保健公司）在测量血糖时的准确性和精密度，以及使用全血和血浆诊断犊牛低血糖状态的诊断准确性。总共49头雄性犊牛（体重：46.3±0.8千克）在出生后75分钟内放置了颈静脉导管。此后，在相对于第一次和第二次初乳喂养（出生后2小时15分钟和14小时5分钟；喂养速率：体重的7%重量/重量）的特定时间点（-10、10、20、30、45、60、90、120、180、240、360、480和600分钟）从导管中采血。血浆葡萄糖浓度的参考标准方法采用葡萄糖氧化酶-过氧化物酶反应进行比色法测定，一式两份。使用林氏一致性相关系数（CCC）、决定系数（精密度）和布兰德-奥特曼图评估血糖仪与参考标准之间的数据一致性。此外，建立了一个混合线性回归模型，以参考方法为结果，血糖仪和重复测量的时间为解释变量，犊牛为随机效应。在<4.44毫摩尔/升的阈值下计算使用犊牛全血和血浆的血糖仪的灵敏度（Se）、特异性（Sp）和曲线下面积（AUC），以确定低血糖。当用于1303份血浆样本时，血糖仪的精密度（CCC = 0.95，R = 0.93）和准确性（AUC = 0.98）非常高。尤登指数显示，当与血浆一起使用时，血糖仪的阈值<4.45毫摩尔/升，Se为94.2%，Sp为91.9%，92.5%的样本被正确分类，表明诊断准确性高。当使用全血时，在476份样本上使用时，精密度（CCC = 0.85，R = 0.73）和准确性（AUC = 0.92）较高。尤登指数显示，当与犊牛全血一起使用时，血糖仪的阈值<4.95毫摩尔/升，Se为95.6%，Sp为80.3%，84.7%的样本被正确分类，表明在农场使用时诊断准确性高。总之，这款血糖仪在使用血浆和全血测量犊牛血糖方面得到了验证。该血糖仪可以测量犊牛的血糖状态，可能有助于临床和农场使用以做出干预决策。
