Frontiers in Pediatrics (Jul 2022)

Stability of novel urinary biomarkers used for lupus nephritis

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

DOI
https://doi.org/10.3389/fped.2022.974049
Journal volume & issue
Vol. 10

Abstract

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BackgroundThe 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.MethodsUrine samples were tested by ELISA under shipping conditions, freeze/thaw, ambient and longer-term storage. Statistical analysis was performed via Deming Regression, Bland-Altman and Spearman Correlation Coefficient.ResultsBiomarker 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.ConclusionsRAIL biomarkers are stable following short-term storage at clinically relevant conditions.

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