title: An update on the von Willebrand factor collagen binding assay: 21 years of age and beyond adolescence but not yet a mature adult.
abstract: von Willebrand disease (VWD) is considered to be the most common inherited bleeding disorder. It is diagnosed after a clinical and physical review, with personal and familial evidence of (primarily mucocutaneous) bleeding, and confirmed by laboratory testing. The latter typically entails initial plasma testing of factor VIII coagulant (FVIII:C), von Willebrand factor (VWF) protein (antigen; VWF:Ag), and VWF function, which has classically been assessed using the ristocetin cofactor (VWF:RCo) assay. More recent attention has focused on another functional VWF assay, the collagen binding (VWF:CB) assay, as a possible replacement for the VWF:RCo assay or as a supplementary test of VWF adhesive "activity." Additional laboratory testing can comprise a battery of confirmatory and VWD subtype assisting assays, including assessment of VWF:multimers. This review updates our knowledge of VWD diagnostics with a particular emphasis on the VWF:CB assay. There is good evidence now in place that an optimized VWF:CB assay can significantly reduce the diagnostic error rate otherwise arising from the use of a test panel restricted to including the VWF:RCo assay as the sole functional VWF assay. Nevertheless, the VWF:CB assay should not be used to wholly replace the VWF:RCo assay in phenotypic testing but rather as a supplementary assay. However, with some thought and justification, the VWF:CB assay can be used to partly replace the VWF:RCo assay in some "screening" applications and can also be used to abrogate the need to perform routine VWF:multimers in most test cases.
authors.affiliation: Department of Haematology, Institute of Clinical Pathology and Medical Research (ICPMR), Westmead Hospital, Westmead, Australia. emmanuel.favaloro@swahs.health.nsw.gov.au
authors.forename: Emmanuel J
authors.initials: EJ
authors.lastname: Favaloro
mesh_terms: D003094:Collagen / Q000378:metabolism*; D003951:Diagnostic Errors; D006801:Humans; D012310:Ristocetin / Q000378:metabolism; D014842:von Willebrand Diseases / Q000175:diagnosis*; D014841:von Willebrand Factor / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism
chemical_list: D014841:von Willebrand Factor; D012310:Ristocetin; D003094:Collagen