In vitro quality of platelets during prolonged storage after washing with three platelet additive solutions

Background and Objectives Patients with anaphylactic transfusion reactions require washed platelet concentrates (PCs) for subsequent platelet (PLT) transfusions. New PLT additive solutions (PASs) contain substances that might be beneficial for the preservation of PLT function during storage. This study compares the quality of PLTs washed and stored with T‐Sol, Composol or SSP+. Study Design and Methods Fifteen buffy coats were pooled and divided into three parts. PCs with 30% plasma and 70% PAS (T‐Sol, Composol or SSP+) were prepared. Washing was performed on day 5 of storage. Ten PCs were prepared and washed with each PAS. In vitro variables including haemostatic function (clotting time and clot retraction) were analysed on day 5 before, directly after and up to 2 days after washing. Results Swirling was well preserved, and pH was within acceptable limits (6·4–7·4) during storage for all PASs. The PLT number was reduced by washing for all PASs, and T‐Sol PCs had a further decrease during storage. PLTs in T‐Sol were spontaneously more activated and had lower capacity to respond to an agonist than Composol or SSP+ PLTs. The haemostatic function was only slightly changed by washing and during postwashing storage. Conclusion PLTs washed with T‐Sol, Composol or SSP+ had good in vitro quality for two days after washing despite absence of glucose. PLTs in T‐Sol were more affected by the washing procedure and subsequent storage than Composol or SSP+ PLTs as judged by higher spontaneous activation.