Variation of urine N-acetyl-β-D-glucosaminidase activity in patients with acute kidney injury after percutaneous nephrolithotomy and its clinical significance

Objective:This prospective study aims to discuss the change and clinical significance of N-acetyl-β-D-glucosaminidase(NAG)in patients who occurred with acute kidney injury(AKI)after percutaneous nephrolithotomy(PCNL)by making dynamic observations of the variation of urinary NAG activity.Method:Ninety patients,aging from 35-72(52.8±9.7)years,64males and 26females,undergoing PCNL with normal renal function were enrolled in the study.The variation of urine NAG activity were measured by colorimetric method before and after operation.Serum creatinine(SCr)concentration was also measured before and after operation.Result: After operation,the level of urinary NAG increased significantly to some extent(P0.05).Among all 90patients,there were 11cases experienced with AKI.Then we divided them into AKI group and non-AKI group. There were no difference between the two groups at the aspects of age,sex and basal SCr(P0.05),while there were great differences at the aspects of operation duration,post-operation infection,C-reactive protein and admission day(P0.05).The performance of NAG(the increase range at 24hpoint)as demonstrated by area under the receiver operation characteristics curve for diagnosis of AKI was 0.878(P0.01).At the cutoff of 235. 44%,the sensitivity and specificity of urine NAG were 81.8% and 91.1% respectively.Conclusion:This study demonstrated that urine NAG value did ascend after PCNL in AKI patients.Urine NAG activity is a more sensitive,earlier biomarker to represent the real situation of renal function in time compared with SCr.It might be have clinical value in the diagnosis of AKI.