title: Validation of a new panel of automated chemiluminescence assays for von Willebrand factor antigen and activity in the screening for von Willebrand disease.
abstract: BACKGROUND
  The diagnosis of von Willebrand disease (VWD) largely depends on the results of von Willebrand factor (VWF) antigen and activity. Recently, a new automated VWF:RCo assay on Acustar was developed. This assay panel for VWD also contains a new antigen (VWF:Ag) test. In this study, both chemiluminescence tests (HemosIL VWF:Ag and VWF:RCo) were evaluated.
  
  
  METHODS
  Imprecision, limit of detection (LOD), and linearity were evaluated. Method comparison (with VWF:Ag latex assay and VWF:RCo by aggregometry) was performed and diagnostic performance of the new test panel was examined.
  
  
  RESULTS
  The imprecision was 7%, and the LOD was 0.2 IU/dL for both assays. Dilution series showed a large linearity for both HemosIL VWF:Ag (0-300 IU/dL) and VWF:RCo (0-200 IU/dL) and method comparison studies revealed good agreement with the currently used VWD panel. The new panel showed adequate diagnostic performance: diagnostic sensitivity was 100% and diagnostic specificity 82% compared with the VWF:Ag latex assay and VWF:RCo by aggregometry. In addition, the new HemosIL Acustar VWF:Ag and HemosIL Acustar VWF:RCo are more sensitive for VWD than the currently used assays.
  
  
  CONCLUSIONS
  This new VWD test panel has adequate laboratory characteristics and allows fully automated and simultaneous analysis of the VWF:Ag and VWF:RCo.
authors.affiliation: Coagulation Laboratory, Department of Clinical Chemistry, Microbiology and Immunology, Ghent University Hospital, Ghent, Belgium.
authors.forename: C J
authors.initials: CJ
authors.lastname: Verfaillie
authors.forename: E
authors.initials: E
authors.lastname: De Witte
authors.forename: K M J
authors.initials: KM
authors.lastname: Devreese
mesh_terms: D016022:Case-Control Studies; D006801:Humans; D008163:Luminescent Measurements / Q000379:methods* / Q000592:standards; D012016:Reference Values; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014842:von Willebrand Diseases / Q000097:blood* / Q000175:diagnosis*; D014841:von Willebrand Factor / Q000378:metabolism*
chemical_list: D014841:von Willebrand Factor
keywords: Acustar; chemiluminescence; von Willebrand disease; von Willebrand factor antigen; von Willebrand factor ristocetin cofactor activity