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Von Willebrand disease (VWD) is caused by either a qualitative or quantitative deficit of the multimeric glycoprotein known as von Willebrand factor (VWF). VWD affects 1-2% of the world population, making it the most common inherited bleeding disorder. VWF plays a crucial role in primary hemostasis by triggering platelet adhesion to injured vessel walls and promoting platelet aggregation. VWF also protects factor VIII from premature degradation in the peripheral circulation. To diagnose VWD, there are several tests that must be run including ristocetin cofactor activity, VWF antigen quantitative assay, Factor VIII activity, and collagen binding assay. Additional tests are needed to determine the subtype of VWD. The ristocetin cofactor activity can be measured using platelet aggregation or platelet agglutination. Both of these assays measure the agglutination of platelets by VWF in the presence of Ristocetin. The platelets are agglutinated when VWF combines with glycoprotein IbĪ±-V-IX receptors on the platelets. The agglutination causes a decrease in turbidity of the mixture and an increase of light transmitted through the test cuvette. The amount of increased light transmission correlates with the activity of the VWF. PMID: 28804849 PMID: 21186048 Source: Regenstrief LOINC

Basic Part Properties

Part Display Name
von Willebrand factor (vWf).ristocetin cofactor activity actual/Normal
Part Type
Component (Describes the core component or analyte measured)
Created On

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