title: Detection of von Willebrand disorder and identification of qualitative von Willebrand factor defects. Direct comparison of commercial ELISA-based von Willebrand factor activity options.
abstract: Two von Willebrand factor (vWF):collagen binding (activity) assay (CBA) kit methods are commercially available. A monoclonal antibody (MAB)-based enzyme-linked immunosorbent assay (ELISA) system reported to correlate with a standard vWF:ristocetin cofactor (RCof) assay is also commercially available. It is marketed as a vWF:Activity assay and is available in 2 assay version formats. In the present study, these 4 vWF-activity options were compared directly with in-house vWF:CBA ELISAs for their ability to detect von Willebrand disease (vWD) and identify qualitative vWF defects. The 2 MAB-based systems detected vWD but could not specifically identify qualitative vWF defects, although the recently modified Mark II kit was more effective for the latter compared with the original Mark I kit. All vWF:CBA methods, including in-house and commercial, also effectively detected vWD but differed in their ability to identify qualitative vWF defects. Effectiveness was highest using the in-house reference vWF:CBA (using a type I/III collagen mix product from equine tendon), the Gradipore vWF:CBA (also uses equine tendon-derived collagen), or the in-house vWF:CBA methods using type III human collagen at a relatively low concentration (1 or 3 micrograms/mL, without covalent linkage). The IMMUNO vWF:CBA seemed to be the least effective among the vWF:CBA methods for detection of qualitative vWF defects.
authors.affiliation: Department of Haematology, Westmead Hospital, Western Sydney Area Health Service, New South Wales, Australia.
authors.forename: E J
authors.initials: EJ
authors.lastname: Favaloro
mesh_terms: D000818:Animals; D003094:Collagen / Q000276:immunology / Q000378:metabolism; D004306:Dose-Response Relationship, Immunologic; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D006403:Hematologic Tests / Q000379:methods; D006801:Humans; D011933:Reagent Kits, Diagnostic; D013710:Tendons / Q000378:metabolism; D014842:von Willebrand Diseases / Q000097:blood / Q000175:diagnosis*; D014841:von Willebrand Factor / Q000032:analysis* / Q000276:immunology
chemical_list: D011933:Reagent Kits, Diagnostic; D014841:von Willebrand Factor; D003094:Collagen