Quantitative or qualitative assay of platelet von Willebrand factor (vWF) is required for the classification of patients suffering from von Willebrand disease (vWD). The major interest of this classification is the administration of specific and appropriate treatment to each category of vWD patients. However, because platelet lysate is prepared from washed platelets, the analysis of platelet vWF is not performed in routine. To overcome this problem, platelet lysates were prepared either with a new method which does not require washing procedure or with the established protocol, then respective platelet vWF characteristics were compared. Our data show that the two methods provide comparable information required for the characterization of types 1 and 2 vWD patients. With this new procedure, complete phenotypic data including the characteristics of platelet vWF can be obtained from most of the vWD patients.