Abstract: Objective:To study the correlation between the serum level of cystatin C(Cys-C)and coronary heart disease(CHD),and its clinical significance.Methods:The suspected CHD patients were detected using selective coronary angiography,and 164 CHD patients and 99 non-CHD patients were divided into the CHD group and control group,respectively.The serum levels of Cys-C in all cases were tested.The correlations between the coronary artery lesion,Gensini score and Cys-C level were analyzed using Pearson correlation analysis.Results:Compared with the control group,the levels of Cys-C in CHD group significantly increased(P<0.05).Among CHD group,the levels of Cys-C in unstable angina pectoris group were higher than that in stable angina group(P<0.05),but the levels of Cys-C in acute myocardial infarction group were lower than that in stable angina group(P<0.05).The area under the ROC curve of CHD diagnosed by Cys-C was 0.711(P<0.05).Taken 1.105 mg/L as the Cut-off value,the sensitivity and specificity of CHD diagnosed by Cys-C were 73.2% and 55.6%,respectively.The level of Cys-C was positively related with the Gensini score(r=0.332,P<0.05) and the number of coronary artery lesion(r=0.413,P<0.05).Conclusions:Cys-C could be used as a noninvasive predictor of CHD,which is closely related to the degree of coronary artery lesion.