Department of Clinical Studies, University of Guelph, Guelph, ON, N1G 2W1, Canada.
Department of Pathobiology, University of Guelph, Guelph, ON, N1G 2W1, Canada.
BMC Vet Res. 2022 Nov 4;18(1):389. doi: 10.1186/s12917-022-03489-w.
In humans, kidney injury molecule-1 (KIM-1) is a biomarker of acute kidney injury that can be quantified in urine. Preliminary investigation in cats with experimentally induced acute kidney injury showed that KIM-1 urine concentration correlated with kidney injury histopathology scores. A lateral flow assay (LFA) has recently become available for patient-side feline KIM-1 measurement. In vitro parameters of the assay have not yet been determined. The objectives of this study were to determine detection of KIM-1 in urine stored at different temperatures over time, to establish the linear range of the LFA, and to assess the intra-assay repeatability of measurements. RESULTS: Ten urine samples with a range of KIM-1 concentrations were stored at room temperature (22 C), 4 C or -20 C, and tested with the LFA on days 0, 1, 2, 3, 7, 14, and 30. The concentration of KIM-1 in samples was not significantly different from the day 0 value, except one sample that had been stored for 30 days at room temperature yielded a significantly higher value. The assay results had a correlation coefficient of 0.922. The mean coefficient of variation for all samples was 15.7%. The slope of the curve of expected versus measured values in samples diluted two-fold nine times was 0.908, and results were linear over all dilutions.
The LFA for feline KIM-1 yields consistent results from stored urine samples. These characteristics will allow for KIM-1 to be measured retrospectively if immediate testing is not feasible. Within assay precision was high, and linearity over 9 logs of dilution suggests suitability for a range of subclinical and clinical kidney injuries.
在人类中，肾损伤分子-1（KIM-1）是急性肾损伤的生物标志物，可在尿液中定量。在实验诱导的急性肾损伤的猫中进行的初步研究表明，KIM-1 尿浓度与肾损伤组织病理学评分相关。最近，一种侧向流动测定法（LFA）可用于患者猫的 KIM-1 测量。该测定的体外参数尚未确定。本研究的目的是确定在不同温度下随时间储存的尿液中 KIM-1 的检测，确定 LFA 的线性范围，并评估测量的批内重复性。结果：十种 KIM-1 浓度范围的尿液样本分别在室温（22°C）、4°C 或-20°C 下储存，并在第 0、1、2、3、7、14 和 30 天使用 LFA 进行检测。除了在室温下储存 30 天的一个样本产生了明显更高的值外，样本中的 KIM-1 浓度与第 0 天的值无明显差异。测定结果的相关系数为 0.922。所有样本的平均变异系数为 15.7%。在将样本稀释两倍九次的情况下，预期值与实测值曲线的斜率为 0.908，并且所有稀释度均呈线性。结论：猫 KIM-1 的 LFA 可从储存的尿液样本中获得一致的结果。如果立即进行测试不可行，则这些特征将允许对 KIM-1 进行回顾性测量。批内精密度高，9 个对数稀释度的线性度表明其适用于一系列亚临床和临床肾脏损伤。
