FIGURE 1.

Overview of the study design. The impact of preservation (n = 6) and non‐preservation (n = 5) BCT and BPI during blood storage at room temperature on EV stability (rEV recovery and EV morphology), sample quality (haemolysis, platelet activation, residual platelets and lipoprotein particles (presumably chylomicrons)), ex‐vivo release of blood‐cell derived EV subtypes (activated platelet EV, non‐platelet EV and erythrocyte EV) and EV omics profile (LC–MS/MS proteomics and small RNA sequencing) was evaluated. In the BCT evaluation phase of the study, the impact of 10 BCT on short‐term blood storage (T1) was assessed. Based on these experiments, performance metrics were developed to enable robust and objective comparisons between BCT. In the BPI evaluation phase of the study, a selection of 4 BCT with favourable performance characteristics, and a BCT marketed for EV preservation (*), was additionally evaluated against three clinically relevant sample processing time intervals (T1–T3) to determine the ability of BCT to stabilize EV during blood sample storage over time. The selected time points between blood draw and processing were 1 h (T1) and 8 h (T2) to mimic immediate and same day processing (short‐term stabilizing efficiency), and 72 h (T3) to assess long‐term stabilizing efficiency.