Ristocetin-induced platelet aggregation of the patient. (A) Ristocetin-induced platelet aggregation of the patient and age- and sex-matched healthy control subject. The concentration of ristocetin used in each test is indicated; in all cases, the VWF concentration was 20 IU/dL. (B) Crossover aggregometry assay using gel-filtered platelets from normal control (Plt ctrl, 140 000/µL) in the presence of the patient’s PPP and platelets from the patient at the same count with PPP from normal control. The latter was used at the same VWF concentration present in the patient’s plasma (2 µg/mL) by diluting it with plasma of a subject with type 3 VWD. Ristocetin was used at 0.6 mg/mL. (C) Ristocetin-induced aggregation of gel-filtered platelets from a healthy control subject tested with the recombinant VWF constructs indicated in the figure. In all cases, the VWF concentration was 20 IU/dL.