In an examination of 71 children undergoing a cardiopulmonary bypass (CPB) [333], the children who developed acute kidney injury (AKI) showed significantly elevated levels of serum and urinary NGAL 2 hours after the CPB, with areas under the receiver operating characteristic curve (AUC) of 0.998 and 0.906, respectively; this study was the first to indicate the utility of biomarkers for the early diagnosis of AKI. This evidence concerns the gene LCN2 and acute kidney injury.