Evaluation of an automated von Willebrand factor activity assay in von Willebrand disease

Clin Appl Thromb Hemost. 2011 Nov-Dec;17(6):E25-9. doi: 10.1177/1076029610379848. Epub 2010 Aug 19.

Abstract

We evaluated the use of the turbidimetric HemosIL von Willebrand Factor (VWF) Activity assay (VWF:Act) on the STA-R automated coagulometer (Stago, Asnières, France) for the diagnosis of von Willebrand disease (VWD). For this, we prospectively screened 268 patients. As a second part, we retrospectively assayed 111 patients with well-defined VWD subtype. In the first prospective study, we demonstrate that in most cases of VWD, VWF ristocetin cofactor activity (VWF:RCo) and VWF:Act are highly correlated but that they both cannot be considered a good screening assay when used alone, since they could miss about 25% of VWF abnormalities. However, the association of VWF:Act analysis and the Platelet Function Analyzer-100 (PFA-100) test constitutes an excellent screening strategy. In our second retrospective study concerning VWD subtypes, VWF:RCo and VWF:Act were well correlated but could be very discrepant, especially for some cases of type 2M VWD. We consider that VWF:RCo remains the "reference assay" for VWD subtype classification.

MeSH terms

  • Automation
  • Blood Coagulation Tests / instrumentation*
  • Blood Coagulation Tests / methods
  • Humans
  • Prospective Studies
  • Reference Standards
  • Retrospective Studies
  • von Willebrand Diseases / blood*
  • von Willebrand Diseases / classification
  • von Willebrand Diseases / diagnosis
  • von Willebrand Factor / analysis*

Substances

  • von Willebrand Factor