Although cystatin C was independently associated with the presence of asymptomatic CAD,in the ROC analysis, the AUC for cystatin C falls into the range 0.6–0.7, which indicates the predictive value of cystatin as a sole marker was only moderate, and the cut-off value of 0.825 mg/L can not be categorized as ideal value to identify asymptomatic CAD effectively. This evidence concerns the gene CST4 and coronary artery disorder.