CST3 and acute kidney injury: Our study has several limitations, including the following: 1) it was a single-center study with a relatively small number of patients; 2) the definition of AKI used in this study was based on changes in the eGFR according to the Schwartz formula and using serum creatinine, which has several drawbacks, as previously mentioned, and might have compromised the accuracy of serum cystatin C for the detection of AKI.