diagnosis

Last reviewed 01/2018

Diagnosis is based upon:

  • assays of von Willebrand's Factor:
    • increased template bleeding time
    • evaluation of vWF protein - vWF:Ag, vWF:R - reduced in type I, normal/reduced in type II, greatly reduced in type III
  • ristocetin cofactor activity - ristocetin fails to induce platelet aggregation in von Willebrand's patients because of lack of vWF:R - a cofactor for ristocetin