Von Willebrand Factor Antigen

Von Willebrand Factor (VWF) antigen is an immuno-turbidimetric assay based on the agglutination of latex microparticles coated with antibodies specific for VWF added to the patient's plasma. The antigen-antibody reaction increases the turbidity of the reaction medium which is measured photometrically. The degree of turbidity and absorbance is directly related to the function of VWF level present in the patient's plasma.

Von Willebrand disease is diagnosed with a group of tests (factor VIII activity, von Willebrand factor antigen, von Willebrand factor activity, collagen binding assay and multimer analysis) in the context of the patient's medical history and clinical presentation. Von Willebrand antigen can be used to monitor therapeutic efficacy of treatment with DDAVP (desmopressin) or von Willebrand factor concentrates in patients with vWD.

Like all antigenic tests, the vWF assay cannot detect the rare type 2 von Willebrand disease variants whose level of VWF antigen is normal.