vWFRistocetinAktivität

vWF:Ristocetin cofactor activity (vWF:RCo) is a functional assay used to measure the activity of von Willebrand factor (vWF), a plasma protein that plays a crucial role in primary hemostasis. vWF binds to platelet membrane glycoproteins (GP) Ib and GPIIb/IIIa, facilitating platelet aggregation and adhesion to the vascular endothelium. Ristocetin is a lectin that binds to high-mannose carbohydrates on vWF, inducing a conformational change that exposes binding sites for GP Ib. This interaction is dependent on the presence of calcium ions. vWF:RCo is measured by incubating patient plasma with ristocetin and calcium ions, followed by the addition of a platelet-rich suspension. The extent of platelet aggregation is then quantified, with higher vWF:RCo values indicating increased vWF activity. This assay is commonly used in the diagnosis and management of bleeding disorders, particularly those related to vWF deficiency or dysfunction. Abnormal vWF:RCo results may prompt further investigation into the underlying cause of the disorder and guide appropriate therapeutic interventions.