INTENDED USEAn enzyme-linked immunosorbent assay (ELISA) for the quantitative determination of Von WillebrandFactor Antigen (VWF: Ag) in citrated human plasma. For In Vitro Diagnostic Use.SUMMARY THE TESTVon Willebrand Factor Antigen (VWF:Ag or Factor VIII-related protein) is a plasma protein found incirculation combined by non-covalent interactions with Factor VIII (FVIII:C), a pro-coagulant protein alsoknown as the anti-hemophilic factor. These two proteins show distinct biochemical and functionalproperties as well as different antigenic determinants; their plasma levels may vary independently ofeach other. Deficiency of FVIII causes classic hemophilia while deficiency of VWF causes VonWillebrand disease. VWF:Ag plays a very important role in hemostasis. The prevalence of Von Willebrand disease has been estimated to be 1-3% of thegeneral population. Approximately 80% of Von Willebrand disease patients have a type I deficiency.The laboratory diagnosis of Von Willebrand disease may require both quantitative and qualitative(functional) determinations.PRINCIPLE OF THE TESTREAADS VWF:Ag assay is a sandwich ELISA. A capture antibody specific for human VWF is coated to96-microwell polystyrene plates. Diluted patient plasma is incubated in the wells, allowing any availableVWF:Ag to bind to the anti-human VWF antibody on the microwell surface. The plates are washed toremove unbound proteins and other plasma molecules. Bound VWF:Ag is quantitated using horseradishperoxidase (HRP) conjugated anti-human VWF detection antibody. Following incubation, unboundconjugate is removed by washing. A chromogenic substrate of tetramethylbenzidine (TMB) and hydrogenperoxide (H2O2) is added to develop a colored reaction. The intensity of the color is measured in opticaldensity (O.D.) units with a spectrophotometer at 450nm. Patient VWF:Ag in relative percentconcentration is determined against a curve made from the reference plasma provided with the kit. Refer to product package insert.
A collection of reagents and other associated materials intended to be used for the quantitative measurement of coagulation factor VIII-associated antigen, also known as von Willebrand antigen, in a clinical specimen using an enzyme immunoassay (EIA) method.