Objective To establish a magnetic particle chemiluminescence for the determination of urinary typeⅣ collagen(ⅣC),and to investigate the role of urinaryⅣC in membranous nephropathy(MN). Methods A magnetic particle chemiluminescence was established for the determination of urinaryⅣC. The performance(determination limit,linear range,accuracy,precision,recovery rate and sensitivity) was verified. The receiver operating characteristic(ROC)curve was used to evaluate the efficiency of urinaryⅣC in the diagnosis of MN. The urinaryⅣC levels of 274 patients with chronic kidney disease(CKD) was determined,and the changes of urinaryⅣC levels in different pathological types and different CKD stages were compared.Results UrinaryⅣC was determined by magnetic particle chemiluminescence,and the standard curve was drawn,with the equation ofY= 42.802X2+10626X-10856(r2=0.999). The lower determination limit was 1.48 ng/mL,the within-run coefficients of variation(CV) for low-level, middle-level and high-level samples were 4.22％,8.16％ and 3.46％,and the between-run CV for low-level and middle-level samples were18.23％ and 17.61％. The average recovery rate was 97.0％. ROC curve showed that the area under curve (AUC)of urinary ⅣC in the diagnosis of MN was 0.875 [95％ confidence interval (CI)0.837-0.913]. The optimal cutoffvalue of urinary ⅣC was 4.15 ng/mL. The sensitivity was 79.0％,and the specificity was 86.7％. Comparedwith healthy control group,the levels of urinary ⅣC in MN group,mesangial proliferative glomerulonephritis(MsPGN) group and non-membranous nephropathy (N-MN)group were increased(P<0.01). Comparedwith N-MN group,the levels of urinary ⅣC in MN group and MsPGN group were increased (P<0.01). ForCDK staging,there was a statistical significance in urinary ⅣC level between CKD1 group and CKD2,CDK3,CDK4 groups(P<0.01). There was no statistical significance between CKD1 and CKD5 groups (P>0.05).Conclusions Magnetic particle chemiluminescence for the determination of urinary ⅣC is simple,reliable andinexpensive,and it plays a role for the diagnosis and prognosis of MN.%目的 建立检测尿Ⅳ型胶原(ⅣC)的磁微粒化学发光法,并探讨尿ⅣC在膜性肾病(MN)中的临床应用价值.方法 制备适用于尿ⅣC检测的标准品,建立检测尿ⅣC的磁微粒化学发光法,并对该方法的检测性能(检测限、线性范围、正确度、精密度、回收率及分析灵敏度)进行确认.采用受试者工作特征(ROC)曲线评估尿ⅣC对MN的诊断效能.采用该方法检测274例慢性肾病(CKD)患者及83名体检健康者(正常对照组)尿ⅣC水平,分析不同病理类型及不同分期的CKD患者尿ⅣC水平的变化.结果 磁微粒化学发光法检测尿ⅣC的标准曲线拟合方程为Y=42.802X2+10626X-10856(r2=0.999);最低检测限为1.48 ng/mL.低值、中值和高值样本的批内变异系数(CV)分别为4.22％、8.16％和3.46％,低值和中值批间CV分别为18.23％、17.61％,平均回收率为97.0％.ROC曲线分析显示,尿ⅣC诊断MN的曲线下面积(AUC)为0.875[95％可信区间(CI)0.837～0.913],最佳临界值为4.15 ng/mL,敏感性为79.0％,特异性为86.7％.MN组、系膜增殖性肾小球肾炎(MsPGN)组、非膜性肾病(N-MN)组尿ⅣC水平均明显高于正常对照组(P<0.01),MN组、MsPGN组尿ⅣC水平均明显高于N-MN组(P<0.01).将MN患者根据CDK分期分为5期,CKD1期与CKD2、CKD3、CKD4期比较,尿ⅣC水平差异均有统计学意义(P<0.01),而与CKD5期比较差异无统计学意义(P>0.05).结论 建立的磁微粒化学发光法操作简便、性能稳定可靠且价格低廉,适宜在临床推广应用,尿ⅣC对MN的诊断及预后判断具有较高的临床应用价值.
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