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

Summary 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 : RC o assay on Acustar was developed. This assay panel for VWD also contains a new antigen ( VWF :Ag) test. In this study, both chemiluminescence tests (Hemos IL VWF :Ag and VWF : RC o) were evaluated. Materials and Methods Imprecision, limit of detection ( LOD ), and linearity were evaluated. Method comparison (with VWF : A g latex assay and VWF : RC o 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 H emos IL VWF : A g (0–300 IU/dL) and VWF : RC o (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 : A g latex assay and VWF : RC o by aggregometry. In addition, the new H emos IL A custar VWF : A g and H emos IL Acustar VWF : RC o 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 : A g and VWF : RC o.