LCN2 and acute kidney injury: Specific biomarkers for the diagnosis of CRS have not been established yet, therefore the evaluation of biomarkers for acute kidney injury (AKI), including cystatin C (CysC), neutrophil gelatinase-associated lipocalin (NGAL), galectin-3 and soluble urokinase plasminogen activator (suPAR), is becoming more and more important at both diagnosis and prognosis levels.