Cody Ellen M, Rose James E, Huang Bin, Qiu Tingting, Brunner Hermine I, Devarajan Prasad
Division of Nephrology and Hypertension, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.
Division of Biostatics and Epidemiology, Cincinnati Children's Hospital Medical Center, Cincinnati, OH, United States.
Front Pediatr. 2022 Jul 29;10:974049. doi: 10.3389/fped.2022.974049. eCollection 2022.
The Renal Activity Index for Lupus (RAIL) is a composite score of six urinary biomarkers (neutrophil gelatinase-associated lipocalin (NGAL), monocyte chemoattractant protein-1 (MCP-1), kidney injury molecule-1 (KIM-1), ceruloplasmin, adiponectin, and hemopexin) used to monitor lupus nephritis activity in children. We tested stability of RAIL biomarkers prior to meaningful clinical use.
Urine samples were tested by ELISA under shipping conditions, freeze/thaw, ambient and longer-term storage. Statistical analysis was performed Deming Regression, Bland-Altman and Spearman Correlation Coefficient.
Biomarker concentration were comparable to freshly collected urine following storage at -80 °C for up to 3 months, and at 4 or 25 °C up to 48 h followed by -80 °C. Neither shipping on dry or wet ice exposure nor addition of two freeze-thaw cycles led to loss of signal, with excellent Spearman Correlation coefficients under all conditions.
RAIL biomarkers are stable following short-term storage at clinically relevant conditions.
狼疮肾活动指数（RAIL）是六种尿液生物标志物（中性粒细胞明胶酶相关脂质运载蛋白（NGAL）、单核细胞趋化蛋白-1（MCP-1）、肾损伤分子-1（KIM-1）、铜蓝蛋白、脂联素和血红素结合蛋白）的综合评分，用于监测儿童狼疮性肾炎的活动情况。在进行有意义的临床应用之前，我们测试了RAIL生物标志物的稳定性。
通过酶联免疫吸附测定（ELISA）在运输条件、冻融、常温及长期储存条件下对尿液样本进行检测。采用Deming回归、Bland-Altman法和Spearman相关系数进行统计分析。
在-80°C下储存长达3个月，以及在4°C或25°C下储存长达48小时后再在-80°C下储存，生物标志物浓度与新鲜采集的尿液相当。无论是在干冰或湿冰上运输，还是进行两个冻融循环，均未导致信号丢失，在所有条件下Spearman相关系数均极佳。
在临床相关条件下短期储存后，RAIL生物标志物是稳定的。
