Urine microalbumin/creatinine ratio and cystatin-c have been reported to provide an earlier and better predictive value for the diagnosis of diabetic nephropathy than 24-hour urinary microalbumin level and serving as a criteria used in the pediatric RIFLE classification.17-21 In our study, despite a significant increase in urine microalbumin/creatinine ratio in Group IV (p < 0.01), the increase in cystatin-c in this group was not statistically significant (p > 0.05), suggesting that this ratio may represent a more sensitive parameter for renal injury. Here, CST3 is linked to diabetic kidney disease.