FABP1 and acute kidney injury: Urinary L-FABP concentration was discovered by Portilla et al. to be utilized as an early and sensitive predictor of AKI complicating pediatric postoperative cardiac surgery, a 24-fold increase in urinary L-FABP at 4 h postoperatively, an AUC of 0.810, sensitivity of 0.714 and specificity of 0.684 (Portilla et al., 2008).