NGAL: neutrophil gelatinase-associated lipocalin; CS: cross-sectional study; PC: prospective cohort study; USA: the United States of America; UK: the United Kingdom; ELISA: enzyme-linked immunosorbent assay; WHO: World Health Organization classification system; ISN/RPS: the International Society of Nephrology/Renal Pathology Society classification system. QUADAS-2: quality assessment tool for diagnostic accuracy studies 2; “yes” or “low concern”: 1 score; “no” or “high concern” or “unclear”: 0 score. aMedian (interquartile range (IQR)). b.cMedian. (Denmark)d: Bioporto, Gentofte, Denmark. (R&D)e: R&D Systems, Minneapolis, MN, USA. Architect assayf: Abbott Laboratories, Abbott Park, IL, USA. (Boster)g: Boster Biological Technology Co., Ltd. (RayBiotech)h: ELHLipocalin2-001, RayBiotech® Inc., Norcross, GA, USA. ELISAi: BioVendor, Asheville, NC28806, USA; (R&D)j: Quantikine: R&D Systems, Inc.