Abstract: Objective: To evaluate the detection of serum cystatin C(Cys C) and the related indicators in diagnosis of early renal damage in diabetic mellitus patients.Methods: Fifty cases of type 2 diabetes patients and 30 normal subjects were studied;the latex-enhanced turbidimetric immunoassay,enzyme and immune nephelometry were employed to test the levels of serum Cys C,urea,creatinine,glomerular filtration rate and Urinary albumin(U-Alb) using Beckman AU5400 and Beckman IMMAGE800;then the results were compared between the two groups.Results: The levels of serum Cys C,U-Alb and urea in patients with diabetes mellitus were significantly higher than those in control group(P<0.01);however,the difference in the level of serum creatinine was not statistically significant(P>0.05).The area under the receiver operating characteristic curve analysis was 0.95 by Cys C curve,and the sensitivity and specificity were 92.1% and 72.0%,respectively;the area under receiver operating characteristic curve of U-Alb was 0.97,and sensitivity and specificity were 90.5% and 68.2%,respectively.Conclusions: Combination detection of the levels of serum Cys C and U-Alb may provide reliable basis for early diagnosis and intervention of the patients with early diabetic nephropathy.