Von Willebrand Disease

The IMUBIND® vWF Activity ELISA is a quantitative direct enzyme-linked immunosorbent assay (ELISA) for the detection of von Willebrand Factor (vWF) activity in citrated human plasma. It is intended for the assessment of vWF activity in patients where this is deemed useful in the diagnostic process, particularly as an aid in the differential classification of von Willebrand’s disease (vWD). Von Willebrand Factor (vWF) is a complex multimeric adhesive glycoprotein synthesized by endothelial cells and megakaryocytes. It functions as an adhesive protein in haemostasis, binding to collagen and mediating platelet adhesion to the sub-endothelium, playing a role in platelet-platelet interaction, and as a carrier/stabilizer protein for the Factor VIII (FVIII:C). In its mildest form, von Willebrand disease is the most common bleeding disorder with a reported frequency of 1 in 100. Classifications of the disease are based upon clinical observation, patient history and laboratory analysis such as bleeding times, vWF protein levels and vWF activity levels. The differential diagnosis of the two predominant classes of the disease, Type 1 and Type 2 is important as clinical management varies with type.

The IMUBIND® vWF ELISA is an enzyme-linked immunoassay for the measurement of vWF antigen in human plasma.Von Willebrand Factor (vWF) is a large, multimeric protein (molecular weight of 1,000-20,000 kD) composed of repeating 270 kD subunits containing 2050 amino acid residues. It is synthesized by endothelial cells and megakaryocytes, and is present in multimeric form in the basement membrane of the subendothelium, in plasma and platelets. vWF promotes platelet adhesion to damaged endothelium and is a key component in the formation of the platelet plug and stable clot formation. Together with fibronectin and collagen, vWF functions in maintaining vessel wall integrity. vWF also functions as a carrier protein for Factor VIII, the coagulation protein absent in haemophilia A. Von Willebrand disease is a bleeding disorder characterized by decreased levels of circulating vWF protein (Type 1), a complete absence of vWF protein (Type 3), and low vWF activity (Types 2A, 2B, 2M, 2N).