Is the prothrombin time (PT) or activated partial thromboplastin time (aPTT) elevated in von Willebrand disease (vWD)?

By William Aird

The aPTT may be increased in Type 2N vWD (the mutation specifically impairs the ability of vWF to carry FVIII) and Type 3 vWD (since vWF carries and stabilizes FVIII in the circulation, the very low levels of vWF associated with Type 3 vWD result in low FVIII activity).