INTRODUCTION: Von Willebrandfactor (VWF) plays a crucial role in hemostasis: its interactions with endothelialmatrices, platelets, and factor VIII make it a key player in both primaryhemostasis and coagulation. Pathology associated with VWF spans mild to severebleeding manifestations in the case of inherited von Willebrand disease (VWD),the most common congenital bleeding disorder, or acquired von Willebrandsyndrome (AVWS). Conversely, VWF can be associated with thromboticmanifestations in situations related to inflammation, infection, or inheritedor acquired ADAMTS13 defects.

AREAS COVERED: This reviewarticle aims to provide guidance on the use and interpretation of clinicallaboratory assays available to measure VWF and other factors related to VWD.Different VWF tests can be used in different clinical settings for efficientdiagnosis and patient management. Assay limitations are also addressed.

EXPERT OPINION: A myriad oflaboratory assays, from first line to esoteric assays, exist to enable adequatediagnosis of VWD and other diseases influenced by VWF. Clinical investigationsof VWF are complicated because VWF has multiple functions which variably dependon the patient's pathophysiological status. The right choice of assays istherefore critical to provide adequate diagnosis in due time and withreasonable analytical efforts.