Pretransfusion (labeled or unlabeled) and posttransfusion (control or during inflammation) platelet surface markers as determined by flow cytometry. (A) Mean CD62P expression before transfusion was significantly higher in long-term stored platelets (8.62% ± 2.97%) than short-term stored PCs (4.21% ± 3.85%; P < .01). After biotinylation, long-term stored PCs exhibited a significantly higher expression of CD62P (14.10% ± 5.99%) than nonbiotinylated long-term stored PCs (P < .05), whereas the biotinylation of short-term stored PCs did not lead to a significant increase in CD62P expression (4.92% ± 2.13%). (B) Mean CD63 expression was significantly higher in long-term stored PCs (3.84% ± 2.26%) than short-term stored platelets (1.51% ± 0.87%; P < .01). The biotinylation process did not affect CD63 expression for both short- and long-term stored PCs. (C) Phosphatidylserine levels between short- and long-term stored PCs was not significantly different. (D-I) The line plot displays the mean and standard deviation of surface markers over time. Statistical comparisons were performed at each time point using an unpaired t test, alongside a 2-way repeated measures analysis of variance (ANOVA) to assess changes over time and between conditions. Significance levels are indicated as follows: ∗P < .05; ∗∗P < .01; ∗∗P < .001; ∗∗∗∗P < .0001; NS, not statistically significant.