Abstract Text: Background. Basophil Activation Testing (BAT) is a flow cytometry functional approach that enables the ex vivo characterization of basophil reactivity against allergenic molecules. The main focus revolves around democratizing this tool. After having recently developed a streamlined approach to BAT, we wanted to compare two possible strategies for implementing BAT in multi-centric studies: to store blood before or after sample stimulation and processing. Method. Fresh heparin and EDTA blood samples were processed in parallel following two workflows: “collect, store, process & analyze” or “collect, process, store & analyze”. Storage times between 0 and 7 days at temperatures of 18-25°C or 2-8°C were considered. Basophil reactivity to anti-IgEs was assessed using CD45, CD3 and CD294 as gating markers and CD203c and CD63 as activation markers. Results. The “collect, store, process & analyze” workflow showed that blood can be kept at least 2 days at 18-25°C or 2-8°C before further processing without impact on basophil reactivity but significant upregulation of CD203c and slight CD63 decrease after 2 days of storage. The “collect, process, store & analyze” workflow demonstrated that blood can be processed and then kept at least 5 days at 18-25°C or 2-8°C before being analyzed with no significant impact on CD203c or CD63 expressions. Conclusions. The “collect, store, process & analyze” workflow remains a simplified logistical approach but depending on the time available between clinical centers and reference laboratories. The “collect, process, store & analyze” workflow can constitute a workflow improvement to provide significant flexibility.
