Patients with a prolonged bleeding time and normal aggregation tests may have storage pool deficiency: studies on one...

One hundred six patients with storage pool deficiency (SPD) were studied with respect to platelet count, bleeding time, total platelet ATP and ADP, platelet serotonin, and in vitro aggregation. The diagnosis of SPD was made on basis of a prolonged bleeding time, a decreased total platelet ADP, and a diminished level of serotonin. Fifty-one patients from 34 unrelated families had congenital SPD, and 55 patients had acquired SPD. Congenital SPD was a common disorder in patients with a lifelong bleeding tendency and a prolonged bleeding time. The frequency in this group of patients was 18%, about one-half the frequency of von Willebrand's disease (vWd). Twenty-three percent of all patients had normal aggregation responses to ADP, epinephrine, and collagen; 33% had aggregation tracings typical for a secretion defect; and 44% had miscellaneous aggregation abnormalities. These findings indicate that SPD is common, heterogeneous, and not necessarily associated with in vitro aggregation abnormalities.