DEVICE: REAADS von Willebrand Factor Antigen Test Kit (00855360006038)

Device Description: INTENDED USE An enzyme-linked immunosorbent assay (ELISA) for the quantitative determination of Von Willebrand Factor Antigen (VWF: Ag) in citrated human plasma. For In Vitro Diagnostic Use. SUMMARY THE TEST Von Willebrand Factor Antigen (VWF:Ag or Factor VIII-related protein) is a plasma protein found in circulation combined by non-covalent interactions with Factor VIII (FVIII:C), a pro-coagulant protein also known as the anti-hemophilic factor. These two proteins show distinct biochemical and functional properties as well as different antigenic determinants; their plasma levels may vary independently of each other. Deficiency of FVIII causes classic hemophilia while deficiency of VWF causes Von Willebrand disease. VWF:Ag plays a very important role in hemostasis. The prevalence of Von Willebrand disease has been estimated to be 1-3% of the general 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 TEST REAADS VWF:Ag assay is a sandwich ELISA. A capture antibody specific for human VWF is coated to 96-microwell polystyrene plates. Diluted patient plasma is incubated in the wells, allowing any available VWF:Ag to bind to the anti-human VWF antibody on the microwell surface. The plates are washed to remove unbound proteins and other plasma molecules. Bound VWF:Ag is quantitated using horseradish peroxidase (HRP) conjugated anti-human VWF detection antibody. Following incubation, unbound conjugate is removed by washing. A chromogenic substrate of tetramethylbenzidine (TMB) and hydrogen peroxide (H2O2) is added to develop a colored reaction. The intensity of the color is measured in optical density (O.D.) units with a spectrophotometer at 450nm. Patient VWF:Ag in relative percent concentration is determined against a curve made from the reference plasma provided with the kit. Refer to product package insert.