INSTRUMENTATION LABORATORY COMPANY 00020002300 HemosIL von Willebrand Factor Antigen

Determination of ristocetin co-factor activity of von Willebrand factor in human plasma through platelet agglutination

INTENDED USE An enzyme-linked immunosorbent assay (ELISA) for the quantitative determination of Von Willebrand Factor Activity (VWF:Act) in citrated human plasma. For In Vitro Diagnostic Use.SUMMARY OF 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. Deficiency of FVIII causes classic hemophilia while deficiency of VWF causes von Willebrand disease. Von Willebrand Disease is characterized by a deficiency or defect of VWF. Greater than 70% of Von Willebrand disease patients have a type 1 deficiency while approximately 20% have a type II deficiency. The laboratory diagnosis of Von Willebrand disease may require both quantitative and qualitative (functional) determinations to differentiate the two predominant subtypes of the disease, type I and type II. The classification of Von Willebrand disease into subtypes is important in determining the course of clinical treatment. PRINCIPLE OF THE TEST The REAADS VWF:Act assay is a sandwich ELISA. A monoclonal capture antibody specific for the portion of VWF which binds platelets is coated to 96-microwell polystyrene plates. Diluted patient plasma is incubated in the wells. The plates are washed to remove unbound proteins and other plasma molecules. Bound antigen 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 O.D. units with a spectrophotometer at 450 nm. Patient VWF:Act in relative percent concentration is determined against a curve made from the reference plasma provided with the kit. Refer to Product Package Insert.

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.