Advances in diagnosis of von Willebrand disease

Introduction: The diagnosis of von Willebrand disease (VWD) may be difficult and is based on the assessment of bleeding history and several diagnostic assays, which evaluate the pleiotropic function of von Willebrand factor (VWF). Laboratory diagnosis requires a series of assays to determine VWF concentration and function, and factor VIII activity, but no single test is available to explore all VWF activities to confirm or exclude diagnosis.Areas covered: This review describes the advances in diagnosing VWD, starting from how to define and quantify the bleeding history to the new assays exploring VWF activities.Expert opinion: VWD is the most common inherited bleeding disorder, is highly heterogeneous, and its appropriate diagnosis may represent a complex laboratory task, especially for type 2 variants. Until recently, the ristocetin cofactor activity assay has represented the standard method for measuring VWF activity, as its ability to bind to platelets in presence of ristocetin, but it has low sensitivity and high variability of results. Novel assays are increasingly used, are often automated and correlate excellently with the standard assay but sometimes discrepant results may lead to a different classification of VWD. The VWF-collagen binding assay is a useful complementary assay to better categorize type 2 variants.