Resuspension of normal platelets in patient plasma. Aggregation of washed normal platelets resuspended in (A) normal and (B) patient plasma with 1 mmol/L AA (1) or with 1.2 (2), 0.9 (3), or 0.5 (4) mg/mL ristocetin, and inhibition by 10 μg/mL IV.3 of the aggregation induced in patient plasma by 0.5 mg/mL ristocetin (5).