Systematic reviews of NGAL in adults and children similarly demonstrate worse outcomes (mortality and hospital length of stay) in patients with both functional and structural AKI.16,17 Although mortality rates for critically ill children are lower than those for adults, NGAL has been studied extensively to delineate functional vs structural vs. combined in children after cardiac surgery and sepsis,18,19 also showing worse outcomes for patients with structural or combined structural and functional AKI. The gene discussed is LCN2; the disease is acute kidney injury.