LCN2 and acute kidney injury: The study by Schilder and colleagues [1] in the previous issue of Critical Care examines one of the more popular markers of AKI, namely neutrophil gelatinase-associated lipocalin (NGAL), but rather than writing another article on the accuracy of NGAL to diagnose AKI, the authors focus on the effects of renal replacement therapy (RRT) on NGAL levels.