In VWD, prolonged coagulation initiation (R-time or CT) and decreased propagation (K-time and CFT) have been observed.131, 132, 133However, the test parameters were found to correlate with FVIII activity levels but not with VWF activity levels132and the tracings normalized in VWD type 3 patients after suppletion with FVIII concentrates131; these abnormalities are therefore likely explained at least in part by FVIII deficiency and not by the alterations in VWF-mediated hemostasis. This evidence concerns the gene F8 and von Willebrand disease (hereditary or acquired).