However, FVIII:C testing cannot be used in isolation; a normal level of FVIII does not always exclude VWD (FVIII:C levels will be normal in many patients with “mild” type 1 VWD and also in some patients with type 2B and 2M VWD), and an abnormal FVIII:C does not always establish a diagnosis of VWD (hemophilia A is actually more likely). Here, F8 is linked to von Willebrand disease (hereditary or acquired).