Key milestones in the diagnosis of VWD over the past 100 years. New VWF activity assays: VWF:GPIbM (GPIb binding assay for VWF using recombinant mutated GPIb, no ristocetin) or VWF:GPIbR (GPIb binding assay for VWF using recombinant GPIb and ristocetin). ASH, American Society of Hematology; NBDF, National Bleeding Disorders Foundation; NHLBI, National Heart, Lung, and Blood Institute; SSC, scientific and standardization committee; WFH, World Federation of Hemophilia.