vWFRistocetinKofaktorAktivität

vWFRistocetinK is not a standard term in hematology or biochemistry. It most likely refers to the interaction between von Willebrand factor (vWF) and ristocetin, or to a ristocetin-based assay used to assess vWF function. In diagnostic hematology, ristocetin-based tests include ristocetin-induced platelet agglutination (RIPA) and the ristocetin cofactor activity assay (vWF:RCo). These tests evaluate how well vWF mediates platelet adhesion and aggregation in the presence of ristocetin.

von Willebrand factor is a large multimeric glycoprotein produced by endothelial cells and megakaryocytes. It mediates platelet adhesion to subendothelial collagen by binding to the platelet receptor GPIb and to collagen, thereby supporting primary hemostasis. vWF also acts as a carrier for factor VIII. Deficiency or dysfunction of vWF leads to von Willebrand disease, which is categorized into types 1, 2, and 3, reflecting quantitative or qualitative defects.

In the vWF:RCo assay, patient plasma is tested for its ability to agglutinate ristocetin-activated, normal donor platelets. Reduced ristocetin cofactor activity indicates impaired vWF function and supports a diagnosis of von Willebrand disease or related platelet function disorders. The RIPA test assesses ristocetin-induced agglutination of a patient’s own platelets and can help distinguish vWF-related defects from Bernard-Soulier syndrome, a GPIb deficiency.

Laboratory interpretation combines vWF:RCo with vWF antigen levels, factor VIII activity, and multimer analysis as needed. The exact term vWFRistocetinK does not correspond to a recognized standard entity; clarifying the intended concept may be helpful.