AUTHOR=Cody Ellen M. , Rose James E. , Huang Bin , Qiu Tingting , Brunner Hermine I. , Devarajan Prasad 

TITLE=Stability of novel urinary biomarkers used for lupus nephritis

JOURNAL=Frontiers in Pediatrics

VOLUME=10

YEAR=2022

URL=https://www.frontiersin.org/journals/pediatrics/articles/10.3389/fped.2022.974049

DOI=10.3389/fped.2022.974049

ISSN=2296-2360

ABSTRACT=<sec><title>Background</title><p>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.</p></sec><sec><title>Methods</title><p>Urine samples were tested by ELISA under shipping conditions, freeze/thaw, ambient and longer-term storage. Statistical analysis was performed <italic>via</italic> Deming Regression, Bland-Altman and Spearman Correlation Coefficient.</p></sec><sec><title>Results</title><p>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.</p></sec><sec><title>Conclusions</title><p>RAIL biomarkers are stable following short-term storage at clinically relevant conditions.</p></sec>