United States Army Veterinary Corps, Fort Sam Houston, TX, USA.
Department of Ecosystem Science and Management, University of Wyoming, Laramie, WY, USA.
Vet Clin Pathol. 2021 Sep;50(3):354-358. doi: 10.1111/vcp.12990. Epub 2021 Aug 31.
The hematocrit (Hct) or packed cell volume (PCV) reflects the blood volume occupied by red blood cells. The development of point-of-care (PoC) instruments can accelerate the ease of measuring Hct/PCV compared with traditional capillary centrifugation (TCC) methods. However, no studies have compared Hct/PCV levels in cattle at high elevation with other measurement methods.
In this study, we aimed to compare methods to estimate Hcts/PCVs of rangeland cattle at high elevation. We specifically wanted to determine if Hct/PCV levels measured with a commercial PoC instrument (i-Stat with CHEM8+ cartridges [PoC ]) were comparable to Hct/PCV levels measured with traditional laboratory methods.
We assessed the Hct/PCV of 94 mature beef cattle (black Angus; Bos taurus) at ~2195 m above sea level using paired analyses of the PoC and TCC methods from each animal. We used paired samples t-tests to compare mean Hct/PCVs. Correlation analyses relative to the line of identity and Passing-Bablok regression were used to assess systematic and proportional differences, respectively, and Bland-Altman plots were used to assess agreement between the two methods.
The PoC estimated a Hct of 28.2% ± 0.7% (SE), which was lower than the TCC estimated PCV of 39.2% ± 0.5%. The Bland-Altman plot revealed poor agreement between the two methods in addition to a -11% bias for the PoC . The Passing-Bablok regression revealed both systematic and proportional bias between the two methods.
Point-of-care blood instruments were not comparable to TCC methods for quantifying Hct/PCVs of cattle living at high elevations.
血细胞比容（Hct）或红细胞压积（PCV）反映了红细胞在血液中所占的体积。即时检测（PoC）仪器的发展可以加速 Hct/PCV 的测量，与传统的毛细血管离心（TCC）方法相比更加便捷。然而，目前尚无研究比较高海拔地区牛的 Hct/PCV 水平与其他测量方法。
本研究旨在比较高海拔地区牧场牛的 Hct/PCV 估计方法。我们特别想确定使用商业 PoC 仪器（i-Stat 与 CHEM8+ 试剂盒 [PoC]）测量的 Hct/PCV 是否与传统实验室方法测量的 Hct/PCV 水平相当。
我们使用配对分析方法，对 94 头成熟的肉牛（黑安格斯牛；Bos taurus）的 Hct/PCV 进行了评估，这些牛生活在海拔约 2195 米的地区。我们使用配对样本 t 检验比较了两种方法的平均 Hct/PCV 值。相关性分析相对于身份线和通过回归分析分别用于评估系统和比例差异，Bland-Altman 图用于评估两种方法之间的一致性。
PoC 估计的 Hct 为 28.2%±0.7%（SE），低于 TCC 估计的 PCV 为 39.2%±0.5%。Bland-Altman 图显示，两种方法之间的一致性较差，PoC 存在-11%的偏差。通过回归分析显示，两种方法之间存在系统和比例偏差。
即时检测血液仪器不能与 TCC 方法相比，用于量化生活在高海拔地区的牛的 Hct/PCV 值。
