In the ROC curve analysis, the area under the curve (AUC) was confirmed to be 0.8073 for TMAO and 0.6844 for cystatin C. Reflecting their roles as serological gold standards for CKD, creatinine and SDMA exhibited AUC values of 0.9558 and 0.9989, respectively (Figure 3). This evidence concerns the gene CST3 and chronic kidney disease.