Presentation and diagnosis of patients with type 3 von Willebrand disease in resources-limited laboratory.

Von Willebrand disease (VWD) is a bleeding disorder that results from decreased von Willebrand factor (VWF) activity <0.30 iu/mL. Therefore, the diagnosis of type 3 VWD in patients with bleeding requires finding a VWF:Ag and/or VWF:platelet ristocetin cofactor (RiCof) <0.03 iu/mL, no further testing is usually necessary. This is a cohort study that included 64 patients with type 3 VWD who were presented and diagnosed at the National Center of Hematology (NCH) from October 2014 to October 2016. In this study the sensitivity of VWF:Ag is only 78%, the sensitivity of VWF:RiCof is 92% of diagnosed cases. From our results it can be concluded that patients with type 3 VWD are usually presented with moderate/severe mucocutaneous bleeding that is associated with prolonged bleeding time test of >10 min and a family history of similar type of bleeding. This fact was frequently utilized to provisionally diagnose several members of the same family, forming a cohort of patients that is larger than the number of objectively-diagnosed patients included in this study, when they cannot afford to be all tested with VWF:Ag/VWF:RiCof.