When platelets are left in the cold

Storage of platelets typically is at room temperature (RT) in large, gas permeable bags that allow some CO 2 and O 2 exchange.The bags are kept on an orbital shaker in a thermostable cabinet (22±2 ℃).These physical storage conditions were rationally selected following scientific breakthroughs in the previous century (1,2).RT storage was selected over storage at 4 ℃ based on the observation that cold-stored platelets are cleared significantly faster from circulation compared to RT (3).Although gold standard for decades now, RT storage is suboptimal because of the higher risk for bacterial bloom compared to 4 ℃ storage (4).Recent estimates suggest that still between 1:1,000 to 1:2,500 platelet concentrates (PC) are contaminated with bacteria (5).Transfusion of a contaminated concentrate can cause sepsis and because patients often receive multiple units, their individual clinical risk for transfusion transmitted infection is a multiplicate of the mathematical risk for contamination of a single PC (6).It should be noted however that bacterial infection caused by platelet transfusion, and resulting in a serious adverse event is very rare in the EU with only 16 cases on 2.3 million platelet transfusions and one death in 2017 (EU DG Health and Food Safety 147152-10/01/2020).Nonetheless, to limit bacterial contamination PC shelf lives are mandatorily short and typically range from 4 to 7 days.This limitation continuously strains the inventory management of blood banks worldwide.Novel ways to extend platelet shelf life without risking sterility or quality, represent a major goal in transfusion medicine.P C s c a n b e a d m i n i s t e r e d p r o p h y l a c t i c a l l y t o thrombocytopenic patients at risk for bleeding or