The effect of ionophore on platelet aggregation in von Willebrand's disease and in congenital afibrinogenemia. A comparison with ristocetin.

Platelet aggregation in citrated and heparinized plasma by ionophore A 23187 and Ristocetin was studied in normal subjects and in patients with von Willebrand's disease and congenital afibrinogenemia. Aggregation by ionophore was normal in all groups both in citrated and heparinized plasma. Aggregation by Ristocetin in citrated plasma was normal in congenital afibrinogenemia, in normal subjects and in types II and III of von Willebrand's disease. It was absent in classical von Willebrand's disease, type I. In heparinized plasma it was absent in all groups, except in some patients with von Willebrand's disease, type III. It is concluded that ionophore A 23187 behaves in a different way than Ristocetin and has no diagnostic implications.