RESUMO
Objective Analysis and evaluation of cystatin C (Cysc) ,N‐acetyl‐beta‐D‐glucosaminidase (NAG) ,β2‐microglobulin (β2‐MG) ,blood urea nitrogen(BUN) ,serum creatinine(Scr) five biological parameters in the diagnosis of early renal damage caused by the diseases of Systemic lupus eythematosus ,diabetes or high blood pressure .Methods Collecting 61 patients with high blood pressure ,62 patients with systemic lupus eythematosus (SLE) ,59 patients with diabetes ,56 cases of healthy controls .Cysc was e‐valuated by immune transmission turbidimetric method ,latex enhanced immune turbidimetric method was used to detectβ2‐MG ,u‐sing two point method to determine NAG ,enzymatic assay Scr ,UV‐GLDH method was used to measure serum BUN ,and using the statistical method to analyze the data .Results There was no significant difference between healthy controls and patients group (P>0 .05) in BUN and Src levels .However ,there were significant differences in Cysc ,urineβ2‐MG and NAG concentrations (P<0 .01) .Under ROC curve ,the largest square of diagnosis indexes for early renal damage caused by SLE ,diabetes ,high blood pres‐sure were blood NAG ,urineβ2‐MG and Cysc .Compared to a single parameter ,the rate of joint detection in the diagnosis of early re‐nal damage is high ,a joint detection of Cysc ,β2‐MG and urine NAG could enhance the positive rate to 88 .7% ,which was signifi‐cantly higher than the joint detection with two indexes (77 .4% ,70 .9% or 66 .1% ) .Conclusion The most sensitive and specific in‐dex in the diagnosis of early renal damage caused by SLE ,diabetes ,high blood pressure were blood respectively NAG ,urine beta 2‐MG and Cysc .Joint detection has higher detection rate ,sensitivity ,specificity ,and has important clinical value in the early diagnosis of patients with renal damage ,which is suitable for clinical application .