VWF and von Willebrand disease (hereditary or acquired): Regarding, the VWF-dependent platelet adhesion, the 2021 guidelines by the American Society of Hematology (ASH), the International Society on Thrombosis and Hemostasis (ISTH), the National Hemophilia Foundation (NHF), and the World Federation of Hemophilia (WFH), suggest that newer assays measuring the platelet-binding activity of VWF (e.g., VWF:GPIbM, VWF:GPIbR) should be preferred over the VWF ristocetin cofactor assay (VWF:RCo) for the diagnosis of VWD.