Function ex vivo of 111 In‐Labelled Human Platelets Simultaneous Aggregation of Labelled and Unlabelled Platelets Induced by Collagen

The function of 111In-labelled platelets has been assessed by collagen-induced aggregation of platelets in samples of whole blood. The blood samples were drawn after injection of autologous 111In-labelled platelets in 19 subjects undergoing platelet kinetic studies. It was thus possible to measure the aggregability of labelled and unmanipulated platelets simultaneously. 111In-labelled platelets aggregated to the same extent as unmanipulated platelets when tested from 10 min to 24 h after injection of the labelled platelets. The results confirm the assumption that minimal damage is inflicted on the platelets during the isolation and labelling procedures, and support the concept that platelets manipulated in vitro may recover in vivo within a few minutes after reinjection.