Evaluation of an automated von Willebrand factor activity assay in von Willebrand disease.
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.
Trossaërt
Marc
M
Laboratory of Hematology, Haemophilia Center, University Hospital, Nantes, France. marc.trossaert@chu-nantes.fr
Ternisien
Catherine
C
Lefrancois
Armelle
A
Llopis
Laura
L
Goudemand
Jenny
J
Sigaud
Marianne
M
Fouassier
Marc
M
Caron
Claudine
C
D001331:Automation; D001780:Blood Coagulation Tests / Q000295:instrumentation* / Q000379:methods; D006801:Humans; D011446:Prospective Studies; D012015:Reference Standards; D012189:Retrospective Studies; D014842:von Willebrand Diseases / Q000097:blood* / Q000145:classification / Q000175:diagnosis; D014841:von Willebrand Factor / Q000032:analysis*
D014841:von Willebrand Factor