Statistical Analysis Statistical analysis will be performed using SPSS statistical software (version 16; SPSS, Chicago, Illinois). Student-t test or Mann-Whitney test will be used to compare continuous variables and Chi-square test or Fisher's exact test will be used for categorical variables. The diagnostic accuracy of the sNGAL and cystatine C tested in this study for identifying AKI will be evaluated by constructing receiver operating characteristics (ROC) curves. A p-value of <0.05 is considered to be statistically significant. All data will be expressed as mean ± standard deviation unless otherwise stated.