The ISTH-BAT has previously been shown to be a predictor of clinical outcome and replacement therapy in adults with VWD, and interestingly, in that study, the incidence of bleeding was inversely related to baseline von Willebrand factor ristocetin cofactor and factor (F)VIII levels: patients with type 1 VWD and low von Willebrand factor ristocetin cofactor (<10 U/dL) and FVIII (<20 IU/dL) were more likely to suffer from bleeding and require replacement therapy during follow-up [10]. This evidence concerns the gene VWF and von Willebrand disease (hereditary or acquired).