Serum or urinary NGAL is another extensively studied biomarker of AKI and has shown predictive value for AKI, AKI severity, and AKI-related outcomes such as need for renal replacement therapy (RRT) and mortality. Kümpers and colleagues prospectively evalu-ated the prognostic utility of serum NGAL at inception of RRT in 109 critically ill patients with established AKI, of whom 51.4% had sepsis.