红细胞沉降率/C反应蛋白比值联合降钙素原在鉴别诊断系统性红斑狼疮活动和细菌性感染中的价值

目的 评价红细胞沉降率(ESR)/C反应蛋白(CRP)比值联合降钙素原(PCT)在鉴别诊断系统性红斑狼疮(SLE)活动和细菌性感染中的价值。方法 将167例SLE患者分为活动组（SLE活动患者）64例和感染组（SLE合并细菌性感染患者）103例，比较两组患者的ESR、CRP、ESR/CRP比值及PCT水平，采用受试者工作特征（ROC）曲线评估上述指标鉴别诊断SLE活动和细菌性感染的价值。结果 活动组患者CRP及PCT均低于感染组，ESR和ESR/CRP比值均高于感染组（P<0.05）。PCT联合ESR/CRP比值鉴别诊断SLE活动和细菌性感染的灵敏度均高于单独检测PCT、CRP、ESR/CRP比值及PCT联合CRP（P<0.05）；而上述5项指标的特异度比较差异均无统计学意义（P>0.05）。PCT联合ESR/CRP比值鉴别诊断SLE活动和细菌性感染的ROC曲线下面积（AUC）均高于CRP、ESR、PCT、ESR/CRP比值、PCT联合CRP（P<0.05）,CRP、ESR、PCT、ESR/CRP比值的约登指数（YI）分别为0.36、0.23、0.40、0.54，对应值分别为22.02mg/L、39mm/h、1.69ng/ml、11.75。结论 PCT和CRP水平在SLE合并细菌性感染者中升高，ESR/CRP比值可作为鉴别诊断SLE活动与细菌性感染的新指标，且ESR/CRP比值<11.75提示SLE合并细菌性感染的可能性大，PCT联合ESR/CRP比值更能提高鉴别诊断SLE活动与细菌性感染的价值。

Value of erythrocyte sedimentation rate/C-reactive protein ratio combined with procalcitonin in differential diagnosis of systemic lupus erythematosus activity and bacterial infection

Objective To evaluate the value of erythrocyte sedimentation rate(ESR)/C reactive protein(CRP) ratio combined with procalcitonin(PCT) in the differential diagnosis of systemic lupus erythematosus(SLE) activity and bacterial infection.Methods A total of 167 patients with SLE were divided into active group(SLE active patients,64 cases) and infection group(SLE patients with bacterial infection,103 cases).Levels of ESR,CRP,ESR/CRP ratio and PCT were compared between the two groups.Value of above indexes in differential diagnosis of SLE activity and bacterial infection was evaluated by receiver operating characteristic(ROC) curve.ResultsCRP and PCT in patients of active group were lower than those of infection group,while ESR and ESR/CRP ratio were higher than those of infection group(P<0.05).Sensitivity of PCT combined with ESR/CRP ratio in differential diagnosis of SLE activity and bacterial infection was higher than that of PCT,CRP,ESR/CRP ratio and PCT combined with CRP(P<0.05),while there were no significant differences among specificity of above 5 indexes（P>0.05）.Area under ROC curve(AUC) for differential diagnosis of SLE activity and bacterial infection by PCT combined with ESR/CRP ratio was higher than that of CRP,ESR,PCT,ESR/CRP ratio and PCT combined with CRP(P<0.05),and Youden index(YI) of CRP,ESR,PCT,ESR/CRP ratio was 0.36,0.23,0.40 and 0.54 respectively,whose corresponding values were 22.02mg/L,39mm/h,1.69ng/ml and 11.75 respectively.Conclusion Levels of PCT and CRP increase in SLE patients with bacterial infection.ESR/CRP ratio can be used as a new index to identify SLE activity and bacterial infection,and ESR/CRP ratio<11.75 indicates a high possibility of bacterial infection.PCT combined with ESR/CRP ratio can improve the differential diagnosis value of SLE activity and bacterial infection.