Iwersen M, Falkenberg U, Voigtsberger R, Forderung D, Heuwieser W
Clinic for Animal Reproduction, Faculty of Veterinary Medicine, Free University of Berlin, 14163 Berlin, Germany.
J Dairy Sci. 2009 Jun;92(6):2618-24. doi: 10.3168/jds.2008-1795.
The objective of this study was to determine the diagnostic performance of an electronic beta-hydroxybutyrate (BHBA) hand-held meter (Precision Xtra) for use in dairy cattle. Specific objectives were to compare the electronic BHBA meter with serum BHBA concentrations determined photometrically and 2 commonly used chemical cowside tests (Ketostix, Ketolac) and to evaluate accuracy in a field study employing 35 investigators. Of the 196 blood samples collected in experiment 1, 17 (8.7%) contained > or =1,200 micromol of BHBA/L of blood and 10 (5.1%) contained > or =1,400 micromol of BHBA/L of blood. Pearson correlation coefficients were highly significant for all tests. The highest correlation coefficient (0.95) was found between measurements of whole blood BHBA determined with the Precision Xtra test and the serum BHBA concentrations determined photometrically. Correlation coefficients between serum BHBA and BHBA in urine using Precision Xtra and Ketostix, and milk using Ketolac were lower. The Precision Xtra test was both 100% sensitive and specific at > or =1,400 micromol of BHBA/L of whole blood. Using milk and urine, positive and negative predictive values were considerably lower for both chemical tests as well as for the electronic meter. In the second study undertaken with 35 bovine veterinary practices, 926 blood samples were collected. In this study, the Precision Xtra test had sensitivities of 88 and 96% at 1,200 and 1,400 micromol of BHBA/L of whole blood, respectively. Specificities were 96 and 97%, respectively. Level of agreement was lower in the second study employing multiple investigators. Considerable differences in variance occurred among investigators. We conclude that the electronic hand-held BHBA measuring system using whole blood is a useful and practical tool to diagnose subclinical ketosis. Sensitivity and specificity are excellent for a cowside test and higher than 2 commonly used chemical dipsticks (Ketostix and Ketolac).
本研究的目的是确定一种用于奶牛的电子β-羟基丁酸（BHBA）手持式血糖仪（Precision Xtra）的诊断性能。具体目标是将电子BHBA血糖仪与通过光度法测定的血清BHBA浓度以及两种常用的化学现场检测方法（Ketostix、Ketolac）进行比较，并在一项由35名研究人员参与的现场研究中评估其准确性。在实验1收集的196份血样中，17份（8.7%）的血液中BHBA含量≥1200微摩尔/升，10份（5.1%）的血液中BHBA含量≥1400微摩尔/升。所有检测的皮尔逊相关系数均高度显著。使用Precision Xtra检测法测定的全血BHBA与通过光度法测定的血清BHBA浓度之间的相关系数最高（0.95）。使用Precision Xtra和Ketostix检测法时，血清BHBA与尿液中BHBA的相关系数，以及使用Ketolac检测法时血清BHBA与牛奶中BHBA的相关系数较低。当全血中BHBA含量≥1400微摩尔/升时，Precision Xtra检测法的灵敏度和特异性均为100%。对于两种化学检测方法以及电子血糖仪而言，使用牛奶和尿液时，阳性预测值和阴性预测值均显著较低。在第二项由35个牛兽医诊所参与的研究中，共收集了926份血样。在本研究中，当全血中BHBA含量为1200和1400微摩尔/升时，Precision Xtra检测法的灵敏度分别为88%和96%。特异性分别为96%和97%。在第二项由多名研究人员参与的研究中，一致性水平较低。研究人员之间的方差存在显著差异。我们得出结论，使用全血的电子手持式BHBA测量系统是诊断亚临床酮病的一种有用且实用的工具。作为一种现场检测方法，其灵敏度和特异性极佳，高于两种常用的化学试纸（Ketostix和Ketolac）。
