The utility of platelet washing using an automated procedure for severe platelet allergic reactions.

Increased use of platelets in patients requiring chronic platelet support has increased platelet transfusion reactions. The authors reviewed more than 300 platelet transfusion reactions, evaluated an automated platelet washing technique, and studied the effectiveness of washing platelets to reduce reactions. Febrile reactions (66%) were most frequently reported, followed by moderate and severe allergic reactions (15%), and urticaria alone (19%). Washed platelets were prepared by an automated technique (IBM/COBE 2991). In vitro studies indicated no apparent adverse effects to the platelets due to the wash procedure, and in vivo studies demonstrated good platelet increments in 10 thrombocytopenic patients. Twenty-two patients with histories of platelet transfusion reactions received a total of 554 washed platelet transfusions. Washed platelets were not effective in reducing febrile transfusion reactions in 16 patients receiving 347 washed products. The efficacy of washed platelets in reducing transfusion reactions was demonstrated in six patients with histories of severe allergic reactions who received 207 washed products. Severe allergic reactions were completely alleviated in this group. In conclusion, automated platelet washing is simple and efficacious in preventing or reducing the severity of allergic reactions to platelet transfusions.