Serum cystatin C in evaluation of the diagnosis in children with impaired renal function

Objective To study the relationship of serum cystatin C(Cys C)level with renal function in pediatric patients with glomerulonephritis.Methods Serum Cys C level was determined by a particle-enhanced turbidimetric immunoassay.Blood urea nitrogen(BUN)was measured by UV-kinetic assay.Serum creatinine(sCr)was measured by enzymatic assay.Endogenous creatinine clearance rate(Ccr)was calculated by muscle oxidase Peroxidase-Antiperoxidase method.Results In glomerulnephritis patients with normal renal function,the level of Cys C was significantly higher than the control group(P 0.01),while the levels of BUN,sCr,Ccr had no significant difference.In glomerulnephritis patients with compensated renal insufficiency,the levels of Cys C and sCr were significantly higher than the control group(all P 0.01),while the level of BUN had no significant difference.In glomerulnephritis patients with decompensated renal insufficiency,the levels of Cys C,BUN,and sCr were significantly higher than the control group(all P 0.01).In all phases of glomerulonephritis,the Cys C level was positively correlated with BUN,sCr,and Ccr(all P 0.01).Conclusions Serum Cys C can sensitively reflect the degree of glomerular filtration impairment and can be used as the serum marker for early diagnosis glomerulonephritis.