Undetected factor VIII in a patient with type 3 von Willebrands disease mistaken as severe haemophilia A

von Willebrand disease (VWD) type 3 is a rare disorder characterized by absent or <0.1 UmL(-1) of ristocetin cofactor (VWF:RCo), and a very low level of factor VIII (FVIII:C). A total absence of FVIII:C has never been reported in type 3 VWD. This case illustrates the effect of severe von Willebrand factor (VWF) deficiency on the factor VIII level.