Platelet aggregation and adhesiveness in classical factor X deficiency and in the abnormal factor X (factor X Friuli) coagulation disorder.

Platelet aggregation to common inductors and to Ristocetin, Thrombofax and Ionophore is normal in congenital factor X deficiency and in factor X Friuli coagulation disorders. Washed normal platelets resuspended in the patient's plasma and in adsorbed normal plasma showed a normal aggregation. On the contrary, normal platelets resuspended in normal serum failed to aggregate. These studies indicate that factor X plays no role in normal platelet aggregation.