Gadisseur, Alain

Mayger, K.

Michiels, Jan J.

Moore, G. W.

Smejkal, P.

Vangenechten, I.

Zapletal, O.

Abstract: Background: von Willebrand disease (VWD) is an inherited bleeding disorder caused by quantitative (type 1 and 3) or qualitative (type 2) von Willebrand factor (VWF) defect. VWD diagnosis and classification require numerous laboratory tests. VWF: glycoprotein Ib (GPIb)-binding activity assays are used to distinguish type 1 from type 2 VWD. Objectives: Three different automated VWF:GPIb-binding activity assays were compared. Patients and methods: BC-VWF:RCo (Siemens Healthcare Diagnostics), HemosIL((R)) VWF:RCo (Instrumentation Laboratory) and INNOVANCE((R)) VWF:Ac (Siemens Healthcare Diagnostics) were performed in a well typed VWD cohort (n = 142). Results: Based on the three most used VWD parameters (FVIII:C, VWF:Ag and VWF:GPIb-binding activity) and using a cut-off of <0.70 for type 2 VWD revealed sensitivity and specificity of, respectively, 92% and 72.4% for VWF:RCo/VWF:Ag, 84% and 89.7% for VWF:GPIbR/VWF:Ag, and 92% and 85.1% for VWF:GPIbM/VWF:Ag, whereas a lowered cut-off of < 0.60 resulted in reduced sensitivity with increased specificity for all assays. Conclusion: VWD classification based on FVIII:C, VWF:Ag and VWF:GPIb-binding activity revealed an overall problem with normal VWF:GPIb-binding activity/VWF:Ag within type 2, especially type 2A/IIE. Although all assays were practically identical, BC-VWF:RCo had higher %CV compared with both new assays but comparable lower limit of quantification (LLOQ) similar to 4 IU dL(-1). No clear improved distinction between type 1 and 2 VWD with new assays was seen. BC-VWF:RCo and HemosIL((R)) are ristocetin dependent, whereas INNOVANCE((R)) does not rely upon ristocetin and is not influenced by VWF polymorphisms increasing VWF:GPIb-binding activity levels. INNOVANCE((R)) seems to be the best choice as a first-line VWF:GPIb-binding activity assay, providing the best balance between sensitivity and specificity for type 2 VWD

Institutional Repository Universiteit Antwerpen

A comparative analysis of different automated von Willebrand factor glycoprotein Ib-binding activity assays in well typed von Willebrand disease patients

A comparative analysis of different automated von Willebrand factor glycoprotein Ib-binding activity assays in well typed von Willebrand disease patients

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Institutional Repository Universiteit Antwerpen