This study showed that in high-risk patients, FST further improves risk stratification.6 Matsuura et al. demonstrated in a retrospective study of 95 ICU patients that response to variable dose of frusemide (frusemide responsiveness, FR) predicts progression to stage 3 AKI better than plasma NGAL (AUC 0.87 vs. 0.80). Here, LCN2 is linked to acute kidney injury.