Our cut-off value of serum NGAL as SCr increase predictor is markedly lower than that found by Quintavalle and colleagues; however, it must be noted that their larger study population (compared with our cohort) was at high-risk for CI-AKI development and had different baseline characteristics, in that it had an estimated GFR ≤ 30 mL/min, which would have been an exclusion criterion for our study. Here, LCN2 is linked to acute kidney injury.