CST3 and acute kidney injury: ROC curve analysis revealed that early absolute or relative increase in cystatin C (as Δcystatin C, within 24 h) had poorer predictive value than Mehran risk score for CI-AKI (AUC=0.584 vs. 0.706, P=0.060; AUC=0.585 vs. 0.706, P=0.058; respectively) (Figure 2).