Novel urinary biomarkers are increasingly utilized for the diagnosis of acute kidney injury (AKI) in dogs. Magnetic-bead based immunoassays for the simultaneous measurement of multiple biomarkers represent a potentially efficient and cost effective tool for investigators; however there is limited data to support their reliable use in dogs. Analytical validation of a commercial multiplex assay for the measurement of five AKI biomarkers: clusterin, cystatin C, kidney-injury molecule 1 (KIM-1), monocyte chemoattractant protein 1 and neutrophil gelatinase-associated lipocalin (NGAL) in canine urine was performed. The effect of pre-analytical factors including potential interfering substances and sample storage methods were investigated. Urine from 110 healthy dogs was used to determine reference intervals for each biomarker measured, according to American Society of Veterinary Clinical Pathology guidelines. Additionally, urine from 21 dogs with pyuria was used to evaluate the impact of pyuria on biomarker concentration.

The assay performed with acceptable accuracy and precision for the measurement of NGAL only. Clinically relevant urine concentrations of bilirubin, haemoglobin, and synthetic colloid solutions led to interference (mean percentage difference > +/− 15% compared to control) with measurement of all or some of the biomarkers. All biomarkers were stable in urine stored at 20–22 °C for 2 h, 4 °C for 12 h, or -20 °C for 6 months. Reference intervals could not be established for KIM-1 due to unacceptable measurement imprecision (intra- and inter assay coefficient of variation 45% and 20% respectively). Urine NGAL concentration was significantly elevated in pyuria (P < 0.001).

新的尿液生物标志物越来越多地用于诊断犬的急性肾损伤 (AKI)。用于同时测量多个生物标志物的基于磁珠的免疫测定代表了研究人员的一种潜在的高效且具有成本效益的工具；然而，支持它们在狗中可靠使用的数据有限。对用于测量犬尿中五种 AKI 生物标志物的商业多重测定进行了分析验证：凝聚素、胱抑素 C、肾损伤分子 1 (KIM-1)、单核细胞趋化蛋白 1 和中性粒细胞明胶酶相关脂质运载蛋白 (NGAL)。研究了包括潜在干扰物质和样品储存方法在内的分析前因素的影响。来自 110 只健康狗的尿液用于确定测量的每个生物标志物的参考区间，根据美国兽医临床病理学会指南。此外，来自 21 只脓尿犬的尿液用于评估脓尿对生物标志物浓度的影响。

该测定以可接受的准确度和精密度进行，仅用于测量 NGAL。胆红素、血红蛋白和合成胶体溶液的临床相关尿液浓度会干扰所有或部分生物标志物的测量（与对照相比平均百分比差异 > +/- 15%）。所有生物标志物在 20-22°C 下储存 2 小时、4°C 下 12 小时或 -20°C 下储存 6 个月的尿液中都是稳定的。由于不可接受的测量不精确性（测定内和测定间变异系数分别为 45% 和 20%），无法为 KIM-1 建立参考区间。脓尿中尿液 NGAL 浓度显着升高（P  < 0.001）。