Abstract
AIM: The aim of this study was to establish reference intervals in healthy children for two novel urinary biomarkers of acute kidney injury, kidney injury molecule-1 (KIM-1) and neutrophil gelatinase-associated lipocalin (NGAL). MATERIALS & METHODS: Urinary biomarkers were determined in samples from children in the UK (n = 120) and the USA (n = 171) using both Meso Scale Discovery (MSD) and Luminex-based analytical approaches. RESULTS: 95% reference intervals for each biomarker in each cohort are presented and stratified by sex or ethnicity where necessary, and age-related variability is explored using quantile regression. We identified consistently higher NGAL concentrations in females than males (p < 0.0001), and lower KIM-1 concentrations in African-Americans than Caucasians (p = 0.02). KIM-1 demonstrated diurnal variation, with higher concentrations in the morning (p < 0.001). CONCLUSION: This is the first report of reference intervals for KIM-1 and NGAL using two analytical methods in a healthy pediatric population in both UK and US-based populations.