Objective To investigate the change of the serum levels of cystatin C,urinary NAG enzyme in the children affected by HSP and its cliracal significance.Methods 60 children with HSP were divided into three groups based on urine routine and abnormal degrees of biochemícal examination results,which were kidney injury group A (KI-Group A),kidney injury group B (KI-Group B),and non-kidney injury group (non-KI-Group).Selected 28 healthy children with the same phase and the same age as the control group.A sandwich enzyme-linked immunosorbent assay(ELISA) was employed to determine the values of cystatin C,urinary NAG enzyme.Results Urinary NAG enzyme in KI-Group A (127.11 ± 15.63) ng/L and KI-Group B (132.75 ± 19.83) ng/L were significantly higher than the control group (111.36 ± 20.10) ng/L (F =7.324,P ＜ 0.05),and there was no difference between non-KI-Group (108.14 ± 13.83) ng/L and the control group.Cystatin C in KI-Group A (1.18 ±0.13) mg/L,KI-Group B (1.19 ±0.17)mg/L and non-KI-Group (1.16 ±0.11)mg/L were all significantly higher than the control group (0.79 ±0.14)mg/L (P ＜ 0.05).Conclusion Cystatin C and urinary NAG enzyme in children with HSP were significantly abnormal,and may be used as early indexes reflecting the glomerular injury.The relationship of the two above indicators had positive correlation,and the combined employment of them had the dadvantages of early detection,high sensitivity and accurate diagnosis.