Von Willebrand factor and disease: a review for laboratory professionals.

Given that von Willebrand disease (VWD) is one of the most common bleeding disorders, the diagnosis or the exclusion is essential in the workup of individuals that have unexplained bleeding. For the clinical laboratory, the challenge is highlighted by the variable presentations of this disorder and the multiple assays that are available from different vendors. This review will give a brief overview of primary hemostasis with a detailed explanation of the biosynthesis, structure, and mechanics of von Willebrand factor (VWF). The final sections will focus on the distinguishing characteristics of the different types of VWD and the array of clinical laboratory tests currently available to assist in the diagnosis.