血管性血友病因子GPIb活性/抗原比值在血栓性血小板减少性紫癜快速鉴别诊断中的价值

The rapid differential diagnostic value of the von Willebrand factor GPIb activity/antigen ratio for thrombotic thrombocytopenic purpura

目的评估血管性血友病因子(vWF)GPIb活性/抗原比值对血栓性血小板减少性紫癜(TTP)急性期的诊断价值。方法前瞻性纳入2018年1月至2019年12月入院的93例同时存在血小板计数<50×10^9/L和溶血表现的疑诊TTP患者,检测ADAMTS13活性,vWF:GPIb活性及vWF抗原,以ADAMTS13活性测定结果作为TTP确诊依据,记录患者PLASMIC临床评分及最终临床诊断。结果22例患者确诊为TTP,ADAMTS13活性的中位数及四分位间距为1.0%(0~7.4%),71例非TTP患者主要诊断为溶血尿毒综合征(HUS)、重症感染、恶性肿瘤、结缔组织病等。TTP患者vWF:GPIb活性、抗原及两者比值均低于非TTP患者(P<0.05),vWF:GPIb活性/抗原比值<0.75对TTP诊断效力最高(敏感度和特异度分别为81.8%、95.2%)。在PLASMIC临床评分判断为TTP高可能性的患者中,vWF:GPIb活性/抗原比值<0.75者有88.9%最终确诊为TTP,比值≥0.75者有15.4%最终确诊为TTP。结论当ADAMTS13活性结果不能及时获得时,基于自动化检测的vWF:GPIb活性/抗原比值有助于疑诊TTP患者的快速鉴别和风险分层。

Objective To evaluate the diagnostic value of the von Willebrand factor(vWF)GPIb activity to antigen ratio for thrombotic thrombocytopenic purpura(TTP)at acute phase.Methods A cohort of 93 patients with suspected TTP and admited to our hospitalfrom January 2018 to December 2019 were prospectively enrolled,we analyzed the levels of vWF:GPIb activity and vWF antigen at acute phase,the diagnosis of acquired TTP was defined as ADAMTS13 activity<10%.The PLASMIC score and final diagnosis of included patients were recorded.Results Twenty-twopatients were diagnosed as TTP,the median(interquartile range)of ADAMTS13 activity were 1.0%(0-7.4%),other diagnoses included hemolytic uremic syndrome(HUS,n=8),severe infection(n=21),malignancy(n=3),connective tissue disease(n=8),et al.The vWF:GPIb activity,vWF antigen,and ratio of vWF:GPIb activity to antigen were all significantly lower in patients with TTP than in those without(P<0.05).The ratio of vWF:GPIb activity to vWF antigen<0.75 could yield a sensitivityof 81.8%and a specificity of 95.2%respectively for TTP.In patients with PLASMIC score≥6,88.9%patients with the ratio of vWF:GPIb activity to vWF antigen<0.75 were confirmed as TTP,and 15.4%patients with the ratio≥0.75 were confirmed as TTP.Conclusions The ratio of vWF:GPIb activity to vWF antigen based on automaticassays might be useful for differential diagnosis and stratification of TTP at acute phase,especially when the ADAMTS13 assay is not available in time.