Validation of a new panel of automated chemiluminescence assays for von Willebrand factor antigen and activity in the screening for von Willebrand disease

Introduction: 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.Materials and 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 0.2IU/dL for both assays. Dilution series showed a large linearity for both HemosIL VWF:Ag (0-300IU/dL) and VWF:RCo (0-200IU/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.Introduction: 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.Materials and 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 0.2IU/dL for both assays. Dilution series showed a large linearity for both HemosIL VWF:Ag (0-300IU/dL) and VWF:RCo (0-200IU/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.A