increased circulating protein level abnormal circulating von Willebrand factor level increased circulating von Willebrand factor level 2020-09-21T10:30:09Z MPheno.ontology increased plasma VWF level increased plasma von Willebrand factor level MP:0031165 increased circulating vWF level increased plasma vWF level increased circulating VWF level elevated blood level of the large multimeric glycoprotein produced by vascular endothelial cells and megakaryocytes that chaperones blood coagulation cofactor factor VIII and tethers platelets to the injured blood vessel wall