LCN2 and acute kidney injury: The results of our study fully confirm dynamic changes in NGAL and prove its good diagnostic value as an early marker for the onset of CI-AKI, considering the data from the ROC analysis (at 4th hour—AUC 0.847, cut-off point of plasma NGAL 90.20 ng/mL, sensitivity 83.33%, specificity of 83.33%).