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Von Willebrand'S Panel
MessageThe Panel includes Platelet Function Assay, Factor VIII Assay, Factor VIII Antigen, and Ristocetin Cofactor.
Test Code
Includes
Preferred Specimen
5 Blue
Minimum Volume
Instructions
Refer to instructions for individual tests included in profile for proper processing and transport instructions.
Transport Container
BLUE/5
Specimen Stability
Reject Criteria (Eg, hemolysis? Lipemia? Thaw/Other?)
Methodology
Refer to Individual Testing
Setup Schedule
Refer to Individual Testing
Report Available
Reference Range
Refer to Individual Reports for Range
Clinical Significance
Von Willebrand's disease (VWD) is a common bleeding disorder represented by a qualitative or quantitative deficiency of Von Willebrand factor (VWF). Patients with decreased levels of VWF frequently have prolonged bleeding times in the presence of normal platelet counts. VWF is present in endothelial cells, megakaryocytes and platelets and circulates in the blood in association with Factor VIII procoagulant protein (VIII:C). VWF is synthesized in the endothelial cells and megakaryocytes. The vWF has a specific antigenic determinant on its surface known as vonWillebrand factor antigen (vWF:Ag). Patients with classic hemophilia A have decreased levels of factor VIII:C, but normal to increased levels of the vWF:Ag, whereas patients with vonWillebrand disease may have decreased to normal levels of both factorVIII:C and vWF:Ag. Ristocetin cofactor activity is that property of the plasma vonWillebrand factor, which is responsible for in vitro platelet agglutination in the presence of ristocetin. Decreased amounts of abnormalities of the factor are associated with the vonWillebrand syndrome.