To diagnose von Willebrand disease (vWD) and to monitor drug efficacy, several tests have been established that are not, however, focused on the platelet adhesion properties of von Willebrand factor (vWF). The new platelet retention test Homburg (RTH) is characterized by a nonthrombogenic filter that retains platelets from blood when it is pressed through this filter. It was the aim of this study to examine the capability of this test to monitor the adhesive properties of vWF after its substitution in vWD or its release by desmopressin infusion. The RTH demonstrated a striking sensitivity for vWF after its release from endogenous storage sites or its supplementation in vivo as well as in vitro, whereas it did not detect an inhibition of platelet aggregability due to aspirin. Desmopressin infusions led to an immediate and highly significant increase of RTH platelet retention, followed by a gradual decline to initial values during the next 4 hours. The transfusion of a vWF concentrate also resulted in RTH data that demonstrated different kinetics than established parameters such as vWF:antigen, vWF:RiCoF, or the PFA-100 in vitro bleeding analysis. Additional in vitro experiments confirmed the correlation of RTH values with vWF concentrations. In conclusion, the RTH may be efficient to complement presently used measures to monitor vWD therapy with desmopressin or vWF concentrates.