VWD is the most common inherited bleeding disorder and is due to a deficiency and/or abnormality of VWF. VWD is inherited in an autosomal-dominant or autosomal-recessive pattern, but women are apparently more symptomatic. Three main criteria are required for correct diagnoses of VWD: (1) positive bleeding history since childhood, (2) reduced VWF activity in plasma, and (3) history of bleeding in the family. The bleeding score, together with baseline VWF levels and family history, have been

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... sed as more evidence-based criteria for VWD. Measurements of a reduced VWF activity in plasma are essential for the diagnosis of VWD; assays for the evaluation of the interactions between VWF and platelet glycoprotein Ib receptor with or without ristocetin, as well as VWF collagen binding, are currently in use. However, other tests such as VWF antigen, factor VIII, ristocetin-induced platelet agglutination, multimeric analysis, VWF propeptide, VWF/FVIII binding assay, and assessment of biological response to desmopressin are necessary to characterize VWD types. Levels of VWF activities Ͻ30 U/dL have been associated with a bleeding phenotype and the presence of mutations in the VWF gene. Learning Objectives • To identify patients at risk for VWD according to their history of bleeding using a specific questionnaire to calculate BS • To use appropriate laboratory tests to classify VWD patients • To predict the bleeding phenotype of VWD and the need for replacement therapy using BS and baseline VWF levels