Clinical significance of serum concentrations of Cystatin C in children with kidney disease

Objective To explore the clinical significance of serum concentrations of Cystatin C (CysC) in children with kidney disease in different disease courses. Methods The serum concentrations of CysC, creatinine(Cr) and endogenous creatinine clearance rate(Ccr) were determined in 182 children with kidney disease. They were divided into five study groups:normal renal function group (73 cases), compensatory renal disfunction group (44 cases), non-compensatory renal disfunction group (35 cases), renal failure group(22 cases) and end stage of renal failure group(8 cases). Meanwhile 70 healthy children were involved in control group. Relationships among CysC, Cr and Ccr were calculated and the diagnostic efficiency was assessed by comparing the areas under the ROC curves. Results The serum concentrations of CysC increased in different courses of renal function impairment in children and were significantly related to the severity of impairment. CysC was positively correlated to Cr and negatively correlated to Ccr. The areas under the ROC curves of Cr and CysC were 0.764 and 0.725. Conclusions The serum concentrations of CysC can accurately identify different impairment grades of renal function and the function of glomerular filtration. As an indicator of early reduction of renal function, its sensitivities and specificities are superior to Cr and Ccr. CysC can be a sensitive endogenous marker for glomerular filtration rate determination. With simple, convenient and applicable assays methods, CysC is essential for early diagnosis of children kidney diseases. Key words: Child;  Kidney diseases;  Cystatin C;  Creatinine;  Endogenous creatinine eharance rate