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Background: Platelet concentrates (PLT) can be manufactured using a combination of apheresis collection devices and suspension media (plasma or platelet additive solution (PAS)). It is unclear how platelet quality and hemostatic function differ across the current in-use manufacturing methods in the United States. The objective of this study was therefore to compare baseline function of PLT collected using different apheresis collection platforms and storage media., Study Design and Methods: PLT were collected at two sites with identical protocols (N = 5 per site, N = 10 total per group) on the MCS® + 9000 (Haemonetics; "MCS"), the Trima Accel® 7 (Terumo; "Trima"), and the Amicus Cell Separator (Fresenius Kabi, "Amicus"). MCS PLT were collected into plasma while Trima and Amicus PLT were collected into plasma or PAS (Trima into Isoplate and Amicus into InterSol; yielding groups "TP", "TI" and "AP", "AI", respectively). PLT units were sampled 1 h after collection and assayed to compare cellular counts, biochemistry, and hemostatic function., Results: Differences in biochemistry were most evident between plasma and PAS groups, as anticipated. MCS and TP had the highest clot strength as assessed by viscoelastometry. AI had the lowest thrombin generation capacity. Both TP and TI had the highest responses on platelet aggregometry. AI had the greatest number of microparticles., Discussion: Platelet quality and function differ among collection platforms at baseline. MCS and Trima platelets overall appear to trend toward higher hemostatic function. Future investigations will assess how these differences change throughout storage, and if these in vitro measures are clinically relevant., (© 2023 AABB.)

Background: The rapid provision of blood products is life-saving for patients with massive hemorrhage. Ideally, RhD-negative blood products would be supplied to a woman of childbearing potential whose Rh type is unknown due to the risk of D-alloimmunization and the potential for hemolytic disease of the fetus and newborn to occur if RhD-positive blood products are transfused. Therefore, there is a need for a test that rapidly determines her RhD type. This study compared the RhD type determined using a rapid ABO and RhD test to the RhD type determined by an immunohematology reference laboratory., Methods: After receiving ethics review board approval, 200 random, unique, deidentified patient samples that had undergone routine pretransfusion testing in an immunohematology reference laboratory using column agglutination technology were collected and tested using a rapid ABO and RhD test (Eldoncard Home kit 2511). The RhD typing results from these two methods were compared to determine the accuracy of the rapid ABO and RhD test., Results: The rapid ABO and RhD test produced results that were concordant with the transfusion service's results in 199/200 (99.5%) of cases, with a negative predictive value of 98.2% and 99.3% sensitivity. The single outlier was likely an RhD variant due to its serological characteristics., Discussion: These data indicate that this rapid ABO and RhD test could be used for the rapid determination of a patient's RhD type, perhaps even in the emergency department, which could guide the selection of blood products provided during their resuscitation., (© 2023 AABB.)

Background: Cold storage of platelets (CS-PLT), results in better maintained hemostatic function compared to room-temperature stored platelets (RT-PLT), leading to increased interest and use of CS-PLT for actively bleeding patients. However, questions remain on best storage practices for CS-PLT, as agitation of CS-PLT is optional per the United States Food and Drug Administration. CS-PLT storage and handling protocols needed to be determined prior to upcoming clinical trials, and blood banking standard operating procedures need to be updated accordingly for the release of units due to potentially modified aggregate morphology without agitation., Study Design and Methods: We visually assessed aggregate formation, then measured surface receptor expression (GPVI, CD42b (GPIbα), CD49 (GPIa/ITGA2), CD41/61 (ITGA2B/ITGB3; GPIIB/GPIIIA; PACI), CD62P, CD63, HLAI), thrombin generation, aggregation (collagen, adenosine diphosphate [ADP], and epinephrine activation), and viscoelastic function (ExTEM, FibTEM) in CS-PLT (Trima collection, 100% plasma) stored for 21 days either with or without agitation (Phase 1, n = 10 donor-paired units) and then without agitation with or without daily manual mixing to minimize aggregate formation and reduce potential effects of sedimentation (Phase 2, n = 10 donor-paired units)., Results: Agitation resulted in macroaggregate formation, whereas no agitation caused film-like sediment. We found no substantial differences in CS-PLT function between storage conditions, as surface receptor expression, thrombin generation, aggregation, and clot formation were relatively similar between intra-Phase storage conditions., Discussion: Storage duration and not condition impacted phenotype and function. CS-PLT can be stored with or without agitation, and with or without daily mixing and standard metrics of hemostatic function will not be significantly altered., (© 2022 AABB.)

Background: Screening for the risk of thromboembolism (TE) due to tranexamic acid (TXA) in patients with severe traumatic injury has not been performed in randomized clinical trials. Our objective was to determine if TXA dose was independently-associated with thromboembolism., Study Design and Methods: This is a secondary analysis of a single-center, double-blinded, randomized controlled trial comparing placebo to a 2-g or 4-g intravenous TXA bolus dose in trauma patients with severe injury. We used multivariable discrete-time Cox regression models to identify associations with risk for thromboembolic events within 30 days post-enrollment. Event curves were created using discrete-time Cox regression., Results: There were 50 patients in the placebo group, 49 in the 2-g, and 50 in the 4-g TXA group. In adjusted analyses for thromboembolism, a 2-g dose of TXA had an hazard ratio (HR, 95% confidence interval [CI]) of 3.20 (1.12-9.11) (p = .029), and a 4-g dose of TXA had an HR (95% CI) of 5.33 (1.94-14.63) (p = .001). Event curves demonstrated a higher probability of thromboembolism for both doses of TXA compared to placebo. Other parameters independently associated with thromboembolism include time from injury to TXA administration, body mass index, and total blood products transfused., Discussion: In patients with severe traumatic injury, there was a dose-dependent increase in the risk of at least one thromboembolic event with TXA. TXA should not be withheld, but thromboembolism screening should be considered for patients receiving a dose of at least 2-g TXA intravenously for traumatic hemorrhage., (© 2022 AABB.)

Background: Fibrinogen concentrates and cryoprecipitate are currently used for fibrinogen supplementation in bleeding patients with dysfibrinogenemia. Both products provide an abundant source of fibrinogen but take greater than 10 min to prepare for administration. Fibrinogen concentrates lack coagulation factors (i.e., factor VIII [FVIII], factor XIII [FXIII], von Willebrand factor [VWF]) important for robust hemostatic function. Cryoprecipitate products contain these factors but have short shelf lives (<6 h). Pathogen reduction (PR) of cryoprecipitate would provide a shelf-stable immediately available adjunct containing factors important for rescuing hemostatic dysfunction., Study Design and Methods: Hemostatic adjunct study products were psoralen-treated PR-cryoprecipitated fibrinogen complex (PR-Cryo FC), cryoprecipitate (Cryo), and fibrinogen concentrates (FibCon). PR-Cryo FC and Cryo were stored for 10 days at 20-24°C. Adjuncts were added to coagulopathies (dilutional, 3:7 whole blood [WB]:normal saline; or lytic, WB + 75 ng/ml tissue plasminogen activator), and hemostatic function was assessed by rotational thromboelastometry and thrombin generation., Results: PR of cryoprecipitate did not reduce levels of FVIII, FXIII, or VWF. PR-Cryo FC rescued dilutional coagulopathy similarly to Cryo, while generating significantly more thrombin than FibCon, which also rescued dilutional coagulopathy. Storage out to 10 days at 20-24°C did not diminish the hemostatic function of PR-Cryo FC., Discussion: PR-Cryo FC provides similar and/or improved hemostatic rescue compared to FibCon in dilutional coagulopathies, and this rescue ability is stable over 10 days of storage. In hemorrhaging patients, where every minute delay is associated with a 5% increase in mortality, the immediate availability of PR-Cryo FC has the potential to improve outcomes., (© 2021 The Authors. Transfusion published by Wiley Periodicals LLC. on behalf of AABB.)

Background: There is a resurgence in the use of low-titer group O whole blood (LTOWB) for hemorrhagic shock. We hypothesized the use of LTOWB compared to component therapy (CT) would be independently associated with improved 24-hour mortality., Study Design and Methods: In this prospective observational study, trauma patients 18 years of age or older with massive transfusion protocol activations were included from August 17, 2018, to May 14, 2019. The primary outcome was 24-hour mortality. Secondary outcomes included 72-hour blood product totals, multiple organ dysfunction scores (MODS), and 28-day mortality. Multivariable logistic regression (MVLR) and Cox regression were performed to determine independent associations., Results: There were no clinically meaningful differences in measures of injury severity between study groups (CT, n = 42; LTOWB, n = 44). There was no difference in MODS between study groups. The unadjusted mortality was not statistically different between the study groups (9/42 [21%] for CT vs. 7/44 [16%] for LTOWB; p = 0.518). In the MVLR model, LTOWB increased the odds of 24-hour survival by 23% (odds ratio 0.81, 95% confidence interval 0.69-0.96; p = 0.017). Adjusted survival curve analysis indicated improved survival at both 24 hours and 28 days for LTOWB patients (p < 0.001). Further stratification showed an association between LTOWB use and survival when maximum clot firmness (MCF) was 60 mm or less (p = 0.009)., Conclusions: The use of LTOWB is independently associated with improved 24-hour and 28-day survival, and does not increase organ dysfunction at 72 hours. Use of LTOWB most impacted survival of patients with reduced clot firmness (MCF ≤60 mm). Collectively, these data support the clinical use and continued study of LTOWB for hemostatic resuscitation., (© 2020 AABB.)

Background: Conventional platelet (PLT) storage at room temperature under continuous agitation results in a limited shelf life (5 days) and an increased risk of bacterial contamination. However, both of these aspects can be ameliorated by cold storage. Preliminary work has suggested that PLTs can be cold stored for up to 3 weeks, while preserving their metabolic activity longer than in PLTs stored at room temperature. As such, in the present study, we hypothesized that the metabolic phenotypes of PLTs stored at 4°C for 3 weeks could be comparable to that of room temperature-stored PLTs at 22°C for 5 days., Study Design and Methods: Metabolomics analyses were performed on nine apheresis PLT concentrates stored either at room temperature (22°C) for 5 days or refrigerated conditions (4°C) for up to 3 weeks., Results: Refrigeration did not impact the rate of decline in glutamine or the intracellular levels of Krebs cycle metabolites upstream to fumarate and malate. It did, however, decrease oxidant stress (to glutathione and purines) and slowed down the activation of the pentose phosphate pathway, glycolysis, and fatty acid metabolism (acyl-carnitines)., Conclusion: The overall metabolic phenotypes of 4°C PLTs at Storage Day 10 are comparable to PLTs stored at 22°C at the end of their 5-day shelf life, while additional changes in glycolysis, purine, and fatty acid metabolism are noted by Day 21., (© 2019 AABB.)

Background: There is renewed interest in the use of whole blood (WB) for resuscitation of patients in hemorrhagic shock. Leukoreduction with platelet-sparing filters and pathogen reduction may be used to improve the safety profile of WB, yet the effects of leukoreduction and pathogen reduction on WB hemostatic function are not well characterized., Study Design and Methods: Blood from 32 healthy group O donors was divided into treatment groups (n = 8 for each group): untreated, pathogen reduced (PR + ), leukoreduced using an in-line filter (LR + ), or PR + LR + . Units were stored without agitation for 21 days between 1° and 6°C, with sampling on days 0 (pre- and post-treatments), 1, 3, 5, 10, 15, and 21 for hemostatic function as assessed by thromboelastometry, thrombin generation, platelet activation factors, and platelet impedance aggregometry., Results: From day 3 (D3) to D15 of storage, platelet count was reduced in PR + /LR + units compared to PR - /LR - units. From D10 to D21 of storage, maximum clot firmness (MCF) was reduced in PR + /LR + units compared to PR - /LR - units. From D3 to D21 of storage, platelet aggregation was reduced in PR + /LR + units compared to PR - /LR - units. Total thrombin generation was similar in all groups from D0 to D21., Conclusions: The combination of LR with a platelet-sparing filter and PR significantly reduces hemostatic function compared to either treatment alone or untreated WB. The clinical consequences of LR and PR of WB in patients with severe bleeding should be examined in trials before both are used in combination in patients., (© 2019 AABB.)