Current and emerging approaches for assessing von Willebrand disease in 2016
von Willebrand disease (VWD) is the most common inherited bleeding disorder and is due to a deficiency and/or abnormality of von Willebrand factor (VWF) VWD is inherited in an autosomal dominant or recessive pattern, but women are apparently more symptomatic. Diagnosis of VWD is still difficult in most countries due to the multiple activities of VWF and the heterogeneity of the disease. VWD is mainly associated with mild mucosal bleeding although gastrointestinal and joint bleeds may occur in severe VWD forms. This review describes the most recent clinical and laboratory procedures for the correct diagnosis of VWD. Assays for the evaluation of the platelet dependent VWF activity (PD VWFact) with or without ristocetin as well as VWF collagen binding (VWF:CB) are currently in use. However, other tests such as VWF antigen (VWF:Ag) factor VIII procoagulant (FVIII:C) ristocetin induced platelet agglutination (RIPA) multimeric analysis (VWF:MA) VWF propeptide (VWFpp) VWF:FVIII binding assay (VWF:FVIIIB) and the assessment of biological response to desmopressin (DDAVP) are necessary to characterize VWD types. Levels of VWF activities <30 U/dL have been associated with a bleeding phenotype and the presence of mutations in the VWF gene.
International journal of laboratory hematology