INS and focal segmental glomerulosclerosis: Distinguishing disease-specific from treatment-induced oxidative changes requires carefully designed studies including healthy age-matched pediatric controls to establish normative ranges; children with other glomerular diseases (e.g., IgA nephropathy, FSGS) to assess INS specificity; comparison of oxidative markers in steroid-naïve vs. steroid-treated patients; longitudinal monitoring during steroid-free remission periods; and correlation with quantitative proteinuria and other disease activity markers independent of treatment.