Urinary neutrophil gelatinase-associated lipocalin as prognostic biomarker for idiopathic nephrotic syndrome in Egyptian children

Background and Objectives: It is important to distinguish steroid sensitive nephrotic syndrome (SSNS) from steroid resistant nephrotic syndrome (SRNS) to avoid initial full dose steroid therapy in the latter. Neutrophil gelatinase-associated lipocalin (NGAL) is a biomarker of acute kidney injury (AKI) even on top of chronic kidney disease (CKD). The aim is to determine urinary NGAL level in children with idiopathic nephrotic syndrome (INS) as a prognostic factor for INS, it can predict steroid resistance early in the course of INS. Subjects and Methods: The present study was carried out on ninety children with INS who were admitted in Pediatric Nephrology Unit of Tanta University Hospital. Thirty healthy children of the same age and sex served as control group. The subjects were subdivided into three groups: Group 1 (SSNS), Group 2 (SRNS), and Group 3 (controls). Patients and controls were subjected to clinical evaluation, laboratory investigations which included 24 h urinary collection for urinary volume and protein, complete blood count, serum cholesterol, serum albumin, blood urea, serum creatinine, and urinary NGAL measurement by enzyme-linked immunosorbent assay. Results: There was a significant increase in uNGAL levels in SRNS when compared with SSNS or controls. There was no significant difference in uNGAL levels between Group 1 and Group 3. ROC curve of uNGAL to predict SRNS had cutoff value >315 at the area under the curve 0.9, sensitivity 86.7%, and specificity 93.3%. There was a significant positive correlation between urinary NGAL level and age of patients and disease duration and serum creatinine level. Conclusions: Urinary NGAL can predict SRNS in INS in children.