ACE and acute kidney injury: In conclusion, we showed that in hospital-acquired AKI: (1) many indices to differentiate are available, but UNa, USG and RFI have the highest specificity to identify prerenal AKI and the best sensitivity for intrarenal AKI; (2) loop diuretics, ACE-inhibitors and AT1- blockers seem to have no significant impact on these parameters/indices; and (3) UNa, USG and RFI can be measured easily, quick and cost saving using spot urine and serum.