title: Screening for von Willebrand disease: contribution of an automated assay for von Willebrand factor activity.
abstract: Measuring von Willebrand factor (VWF) activity is essential to the diagnosis of von Willebrand disease (VWD). The VWF activity is usually assessed based on measurement of the ristocetin cofactor (VWF:RCo). However, that test is technically challenging and has high intra- and inter-assay variabilities. The HemosIL VWF activity (VWF:AC) is a fully automated assay, recently proposed as a good alternative to VWF:RCo for VWD diagnosis. This study was undertaken to assess this new method. First, the analytical performance of VWF:AC on an automated coagulo-meter (ACLTop) was determined, and then this new method was compared with VWF:RCo and the platelet function analyzer (PFA100) for 160 patients referred for VWD screening. The VWF:AC achieved acceptable precision with within-run and between-run coefficients of variation ranging from 2.3% to 14.1%, and linearity from 10% to 100%. Despite some marked differences between VWF:AC and VWF:RCo for 10 plasmas tested, their agreement for VWD diagnosis was good. The VWF:AC had sensitivity similar to that of PFA100 (close to 100%), but better specificity (97.7% vs. 66% or 60%, depending on the cartridge used). The good analytical performance, and the sensitivity and specificity of VWF:AC to detect VWF deficiency renders it a suitable method for VWD screening. Our findings support VWF:AC use for the diagnostic work-up of VWD, paying close attention to concomitant clinical signs and bleeding score, as recommended for VWD.
authors.affiliation: Laboratoire d'Hématologie, Hôpital Necker, AP-HP, Paris, France. dom.lasne@nck.aphp.fr
authors.forename: D
authors.initials: D
authors.lastname: Lasne
authors.forename: C
authors.initials: C
authors.lastname: Dey
authors.forename: M-D
authors.initials: MD
authors.lastname: Dautzenberg
authors.forename: Z
authors.initials: Z
authors.lastname: Cherqaoui
authors.forename: F
authors.initials: F
authors.lastname: Monge
authors.forename: A
authors.initials: A
authors.lastname: Aouba
authors.forename: M-F
authors.initials: MF
authors.lastname: Torchet
authors.forename: D
authors.initials: D
authors.lastname: Geloen
authors.forename: P
authors.initials: P
authors.lastname: Landais
authors.forename: C
authors.initials: C
authors.lastname: Rothschild
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D019540:Area Under Curve; D001331:Automation; D001780:Blood Coagulation Tests / Q000379:methods / Q000592:standards*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D012372:ROC Curve; D012680:Sensitivity and Specificity; D055815:Young Adult; D014842:von Willebrand Diseases / Q000175:diagnosis*; D014841:von Willebrand Factor / Q000032:analysis*
chemical_list: D014841:von Willebrand Factor