Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, Ontario, Canada.
Department of Clinical Studies, College of Veterinary Medicine, University of Florida, Gainesville, Florida, USA.
J Vet Intern Med. 2020 Nov;34(6):2758-2766. doi: 10.1111/jvim.15889. Epub 2020 Sep 23.
Use of different analyzers to measure electrolytes in the same horse can lead to different interpretation of acid-base balance when using the simplified strong ion difference (sSID) approach.
Investigate the level of agreement between 2 analyzers in determining electrolytes concentrations, sSID variables, and acid-base disorders in sick horses.
One hundred twenty-four hospitalized horses.
Retrospective study using paired samples. Electrolytes were measured using a Beckman Coulter AU480 Chemistry analyzer (PBMA) and a Nova Biomedical Stat Profile (WBGA), respectively. Calculated sSID variables included strong ion difference, SID ; unmeasured strong ions, USI; and total nonvolatile buffer ion concentration in plasma (A ). Agreement between analyzers was explored using Passing-Bablok regression and Bland-Altman analysis. Kappa (κ) test evaluated the level of agreement between analyzers in detecting acid-base disorders.
Methodologic differences were identified in measured Na and Cl and calculated values of SID and USI. Mean bias (95% limits of agreement) for Na , Cl , SID , and USI were: -1.2 mmol/L (-9.2 to 6.8), 4.4 mmol/L (-4.4 to 13), -5.4 mmol/L (-13 to 2), and -6.2 mmol/L (-14 to 1.7), respectively. The intraclass correlation coefficient for SID and USI was .55 (95%CI: -0.2 to 0.8) and .2 (95%CI: -0.15 to 0.48), respectively. There was a poor agreement between analyzers for detection of SID (κ = 0.20, 95%CI, 0.1 to 0.31) or USI abnormalities (κ = -0.04, 95%CI, -0.11 to 0.02).
Differences between analyzer methodology in measuring electrolytes led to a poor agreement between the diagnosis of acid-base disorders in sick horses when using the sSID approach.
使用不同的分析仪来测量同一匹马的电解质会导致在用简化强离子差（sSID）方法时对酸碱平衡的不同解释。
研究在确定电解质浓度、SID 变量和患病马匹酸碱紊乱时，两种分析仪之间的一致性水平。
124 匹住院马。
使用配对样本进行回顾性研究。分别使用贝克曼库尔特 AU480 化学分析仪（PBMA）和 Nova Biomedical Stat Profile（WBGA）测量电解质。计算的 sSID 变量包括强离子差、SID；未测量的强离子、USI；和血浆中非挥发性总缓冲离子浓度（A）。使用 Passing-Bablok 回归和 Bland-Altman 分析探讨分析仪之间的一致性。Kappa（κ）检验评估了分析仪在检测酸碱紊乱方面的一致性水平。
在测量的 Na 和 Cl 以及计算的 SID 和 USI 值方面发现了方法学差异。Na、Cl、SID 和 USI 的平均偏差（95%置信区间）分别为：-1.2mmol/L（-9.2 至 6.8）、4.4mmol/L（-4.4 至 13）、-5.4mmol/L（-13 至 2）和-6.2mmol/L（-14 至 1.7）。SID 和 USI 的组内相关系数分别为.55（95%CI：-0.2 至 0.8）和.2（95%CI：-0.15 至 0.48）。在使用 sSID 方法时，两种分析仪对 SID（κ=0.20，95%CI，0.1 至 0.31）或 USI 异常的检测一致性较差（κ=-0.04，95%CI，-0.11 至 0.02）。
在测量电解质方面，分析仪方法学的差异导致在用 sSID 方法诊断患病马匹的酸碱紊乱时，两种分析仪之间的诊断一致性较差。
