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ABSTRACT Objective: Prolong platelet survival and functionality up to 28 days. Methods: A sample of apheresis platelets was evaluated, distributed in 3 groups according to the cryopreservative solution used: DMS05%+2%albumin; DMSO5%+NaC10,9% and DMS05%+Dextrose2%. They were then frozen at -80 °C and thawed at 7, 14 and 28 days. The in vitro survival and viability were assessed by the post-thaw platelet count and the CD41, CD61 and CD42a staining percentages by flow cytometry. The functionality was determined with the percentage of post-stimulation aggregation with INm-thrombin using the Chromo-Log490 aggregometer. The control group (CG) consisted of fresh platelets under constant agitation at 22 °C. Results: A total of 72 platelet aliquots was analyzed. The CG presented a platelet-count of 1934 ± 0.5 × 109/L and a 100% viability. The percentages of CD41, CD61 and CD42a labeling were 99, 98.5 and 96.5%, respectively. The percentage of aggregation was 99%. On day 7 of the post-freezing, the platelet count for groups 1, 2 and 3 was 1,844 ± 102, 1,856 ± 76 and 1,752 ± 226, with the viability of 98, 96 and 95%, respectively. On day 14, the counts were 1,722 ± 238, 1,649 ± 215 and 1,578 ± 223 with the viability of 96, 95 and 94% and, on day 28, they were 1,602 ± 374, 1,438.6 ± 429 and 1,406.6 ± 436, with the viability of 96, 94 and 93%, respectively. Groupl presented a higher expression of membrane antigens. Aggregation percentages were 90, 98 and 89% at day 7, 88%, 98 and 87% at day 14 and 84%, 95 and 82% at day of the 28 post-freezing, respectively, with group2 presenting the best results. Conclusion: The results support cryopreservation as a reasonable method to prolong platelet survival up to 28 days, maintaining its functionality and viability greater than 50%. Objective days Methods evaluated used DMS05%+2%albumin DMS052albumin DMSalbumin DMS05 albumin DMS DMSO5NaC109 DMSONaC DMSO5 NaC10 9 DMSO NaC DMSO5%+NaC10,9 DMS05Dextrose2 DMSDextrose Dextrose2 Dextrose DMS05%+Dextrose2% 80 -8 C 1 postthaw post thaw CD41 CD CD6 CDa cytometry poststimulation stimulation INmthrombin INm thrombin ChromoLog490 ChromoLog Chromo Log490 Log Chromo-Log49 aggregometer (CG Results analyzed plateletcount 193 05 0 5 0. 109L L 109 100 99 985 98. 965 96.5% respectively 99% postfreezing, postfreezing freezing, freezing post-freezing 1844 844 1,84 102 1856 856 1,85 1752 752 1,75 226 95% 1722 722 1,72 238 1649 649 1,64 21 1578 578 1,57 1602 602 1,60 374 14386 438 6 1,438. 42 14066 406 1,406. 436 93 93% antigens 90 89 88 88% 87 84 84% 82 Conclusion 50 50% DMS0 DMSO5NaC10 NaC1 DMSO5%+NaC10, DMS05Dextrose DMS05%+Dextrose2 8 - CD4 ChromoLog49 Log49 Chromo-Log4 19 10 96.5 184 1,8 185 85 175 75 1,7 172 23 164 64 1,6 157 57 1,5 160 60 37 1438 43 1,438 4 1406 40 1,406 DMSO5NaC1 DMSO5%+NaC10 DMS05%+Dextrose ChromoLog4 Log4 Chromo-Log 96. 18 17 16 15 143 1,43 140 1,40 DMSO5NaC DMSO5%+NaC1 1,4 DMSO5%+NaC