Diagnosis of von Willebrand disease

The haemorrhagic diathesis in von Willebrand disease (vWD) is caused by a q uantitative deficiency or a qualitative defect in the von Willebrand factor (vWF) in plasma and/or platelets causing insufficient primary haemostasis. Since vWF binds and protects factor VIII (FVIII) towards random proteolysi s, coagulation may also be impaired in patients with a low plasma level of VWF, and in instances where vWF displays insufficient binding capacity to F VIII. The entity of vWD displays a vast heterogeneity. Apart from rarely oc curring acquired cases, vWD is an inherited disorder of autosomal linkage. The major clinical hallmark in vWD is an increased tendency to mucocutaneou s bleeding that rarely reach life-threatening proportions, unless vWF is se verely reduced or completely absent. Increased bleeding may also occur in s ites such as muscles and joints when the level of FVIII is particularly low . Significant progress has recently been achieved through extensive molecular genetic exploration of various forms of vWD. In order to guide treatment a nd to form a platform for generic investigation, however, accuracy in diagn osis and phenotypic characterization is important. By means of various labo ratory methods, major subclasses of vWD call be differentiated, as presente d in another article of this series. Whereas most of the cases of vWD call quite easily be diagnosed and classified using today's diagnostic methods, the most frequently occurring bleeding disorder of all, vWd type 1 of mild degree, continues to challenge clinicians and diagnostic laboratories. The aim of this paper is to review the laboratory methods most commonly used in diagnostic investigation of the patient suspected of vWD.