Identification of Patients with Storage Pool Deficiency Using ATP Release and Dense Granule Counts

Recent reports have suggested that a significant number of patients with long bleeding times and normal platelet aggregation have storage pool deficiency (SPD). The present study screened 215 patients referred for evaluation of haemostasis because of a clinical bleeding history. SPD was identified by the presence of combined abnormalities in platelet ATP release and electron microscopic dense granule enumeration. Eight percent (17/215) of the patients studied were found to have SPD. Eleven percent (9/80) of patients with prolonged bleeding times had SPD, compared to 6% (8/135) of those with normal bleeding times. Two patients were identified as having both SPD and von Willebrand Disease. Although 12 of 17 SPD patients had prolonged bleeding times and/or abnormal platelet aggregation studies, five patients had neither abnormality and would not have been identified without the more specific tests for dense granule number and function.