BACKGROUND:The Association for the Advancement of Blood and Biotherapies guidelines recommend the use of high-titer COVID-19 convalescent plasma (CCP) for patients with SARS-CoV-2 at high risk of disease progression, including those who are immunocompromised. We hypothesized that conventional plasma units have comparable neutralizing antibody levels to CCP. STUDY DESIGN AND METHODS:Conventional plasma and CCP units were obtained from blood suppliers. Quantitatively measured antibodies to SARS-CoV-2 were assessed using the MesoScale Discovery multiplex electrochemiluminescence immunoassay. Binding antibody distributions were compared with Wilcoxon rank-sum tests. SARS-CoV-2 neutralizing antibodies were analyzed using the GeneScript ELISA-based neutralization assay. The proportion of conventional and CCP units with a percent signal inhibition of ≥80% (as defined by the United States Food and Drug Administration for CCP in 2021) and exact binomial confidence intervals (CIs) were calculated. RESULTS:Among 218 conventional plasma units and 74 CCP units collected between September 2023 and July 2024, the distribution of total antibody binding levels largely overlapped between conventional plasma and CCP, though statistically significant differences in median nucleocapsid and spike Omicron variant concentrations were observed. Median percent signal neutralization was 97.5% (range 3.4%-98.6%) among conventional plasma units and 97.7% (range 95.4%-98.6%) among CCP units. For conventional plasma, 95.0% (95% CI = 91.2%-97.5%) met the neutralization antibody threshold for high-titer CCP. For CCP, 100% (95% CI = 95.1%-100.0%) met the neutralization threshold for high-titer CCP. CONCLUSION:Conventional plasma units demonstrate similar median antibody concentration to CCP units. In countries or regions where licensed CCP is unavailable and titers are unknown, transfusion of multiple conventional plasma units may be of clinical utility.

Introduction: In response to the COVID-19 pandemic, we rapidly implemented a plasma coordination center, within two months, to support transfusion for two outpatient randomized controlled trials. The center design was based on an investigational drug services model and a Food and Drug Administration-compliant database to manage blood product inventory and trial safety. Methods: A core investigational team adapted a cloud-based platform to randomize patient assignments and track inventory distribution of control plasma and high-titer COVID-19 convalescent plasma of different blood groups from 29 donor collection centers directly to blood banks serving 26 transfusion sites. Results: We performed 1,351 transfusions in 16 months. The transparency of the digital inventory at each site was critical to facilitate qualification, randomization, and overnight shipments of blood group-compatible plasma for transfusions into trial participants. While inventory challenges were heightened with COVID-19 convalescent plasma, the cloud-based system, and the flexible approach of the plasma coordination center staff across the blood bank network enabled decentralized procurement and distribution of investigational products to maintain inventory thresholds and overcome local supply chain restraints at the sites. Conclusion: The rapid creation of a plasma coordination center for outpatient transfusions is infrequent in the academic setting. Distributing more than 3,100 plasma units to blood banks charged with managing investigational inventory across the U.S. in a decentralized manner posed operational and regulatory challenges while providing opportunities for the plasma coordination center to contribute to research of global importance. This program can serve as a template in subsequent public health emergencies.

Background: Splitting apheresis platelet (PLT) units increase available inventory during shortages. The impact of prolonged storage in gas-impermeable aliquot bags on PLT quality in vitro and transfusion outcomes in patients remains uncertain. Study Design and Methods: We assessed in vitro PLT quality and thromboelastography (TEG) in PLTs stored for 8 or 24 h in aliquot bags compared with baseline (T0). Retrospective assessment of response (PLT increment and corrected count increment (CCI)) was conducted among adults (>= 18 years) transfused with split platelet units from January 2021 to June 2022. Results: No differences were observed in PLT and white blood cell (WBC) counts, mean platelet volume, or TEG parameters during storage, except for an increase in TEG R time (meanSD) at 24h (6.1 +/- 0.5min) compared to T0 (4.4 +/- 0.8 min), p=0.0031 one-way ANOVA. Eighty-one patients were transfused 119 split units with a median [IQR] PLT yield of 2.1x10(11)[1.9x10(11) to 2.3x10(11)] and storage duration of 1.6[0.7-9.1] h. The overall median PLT count increment was 6.0x10(3)/uL and CCI was 5.0x10(3), correlating negatively with split unit storage duration (Spearman rho=-0.218, p=0.017). Compared with split transfusions of pathogen-reduced (PR) PLTs, non-PR splits were associated with higher median platelet count increments (7.0x10(3)/mu L vs. 4.0x10(3)/mu L, p=0.0263 Mann-Whitney U) and higher CCIs (6.5x10(3) vs. 3.9x10(3), p=0.0116 Mann-Whitney U) despite no differences in PLT yields (2.1x10(11)/mu L vs. 2.1x10(11)/mu L). Discussion: Storing PLTs in aliquot bags for 8 or 24 h does not adversely affect their quality in vitro. Splitting apheresis PLTs are feasible for adult transfusions during shortages. It may be advisable to prioritize non-PR PLTs for splitting given improved patient responses.

BACKGROUNDCOVID-19 convalescent plasma (CCP) virus-specific antibody levels that translate into recipient posttransfusion antibody levels sufficient to prevent disease progression are not defined.METHODSThis secondary analysis correlated donor and recipient antibody levels to hospitalization risk among unvaccinated, seronegative CCP recipients within the outpatient, double-blind, randomized clinical trial that compared CCP to control plasma. The majority of COVID-19 CCP arm hospitalizations (15/17, 88%) occurred in this unvaccinated, seronegative subgroup. A functional cutoff to delineate recipient high versus low posttransfusion antibody levels was established by 2 methods: (i) analyzing virus neutralization-equivalent anti-Spike receptor-binding domain immunoglobulin G (anti-S-RBD IgG) responses in donors or (ii) receiver operating characteristic (ROC) curve analysis.RESULTSSARS-CoV-2 anti-S-RBD IgG antibody was volume diluted 21.3-fold into posttransfusion seronegative recipients from matched donor units. Virus-specific antibody delivered was approximately 1.2 mg. The high-antibody recipients transfused early (symptom onset within 5 days) had no hospitalizations. A CCP-recipient analysis for antibody thresholds correlated to reduced hospitalizations found a statistical significant association between early transfusion and high antibodies versus all other CCP recipients (or control plasma), with antibody cutoffs established by both methods-donor-based virus neutralization cutoffs in posttransfusion recipients (0/85 [0%] versus 15/276 [5.6%]; P = 0.03) or ROC-based cutoff (0/94 [0%] versus 15/267 [5.4%]; P = 0.01).CONCLUSIONIn unvaccinated, seronegative CCP recipients, early transfusion of plasma units in the upper 30% of study donors' antibody levels reduced outpatient hospitalizations. High antibody level plasma units, given early, should be reserved for therapeutic use.TRIAL REGISTRATIONClinicalTrials.gov NCT04373460.FUNDINGDepartment of Defense (W911QY2090012); Defense Health Agency; Bloomberg Philanthropies; the State of Maryland; NIH (3R01AI152078-01S1, U24TR001609-S3, 1K23HL151826NIH); the Mental Wellness Foundation; the Moriah Fund; Octapharma; the Healthnetwork Foundation; the Shear Family Foundation; the NorthShore Research Institute; and the Rice Foundation.

pH > 6.2, low white blood cell (WBC) counts, PTR >60%, and with transfused platelets found in clots. Study Design/Methods: Whole blood (WB) was collected from transgenic mice expressing green fluorescent protein (GFP) to make PLT units. PLT-rich plasma and PLT pellet were isolated after centrifugation steps; the PLT pellet was resuspended in mouse fresh-frozen plasma. PLT counts, activation, aggregation, and PTR were measured during storage by flow cytometry. Samples were activated with 0.5 U/mL thrombin and labeled with anti-CD41a, labeling all PLTs, and anti-CD62P, labeling activated PLTs. WB from transgenic mice expressing red fluorescent protein (RFP) was also collected. The transfusate was made from fresh RFP WB and fresh or stored GFP PLT unit (1 or 2 days, 20° C) and transfused into wild-type mice (1 10 total PLT). PLT aggregation was measured by activating the transfusate as above, and PLTs expressing both GFP and RFP were considered aggregated. PTR was measured at multiple time points as the percent GFP of the total transfused PLTs (RFP + GFP) in circulation, normalized to the percent GFP of the transfusate. Recipient tails were transected 1 h after transfusion and allowed to clot; GFP and RFP were measured in sections of clotted tails by confocal imaging. Results/Findings: The pH of fresh, 1-, and 2-day stored units were 7.25, 6.75, and 6.0, respectively, with WBC counts <2.08 10 WBC/unit (corrected for mice). Units were cultured and were negative for bacterial growth. The percentage of activated platelets increased as storage duration increased at baseline, and with the addition of thrombin, stored platelets had reduced levels of CD62P and formed fewer aggregates. PTR of fresh, 1-, and 2-day stored PLTs at 24 h was 93.3%, 87.7%, and 0.0%, respectively. Clots of fresh, 1-, and 2-day stored unit recipients after tail transection had 90.2%, 70.7%, and 8.5% GFP/total fluorescent PLTs, respectively. Conclusions: Taken together, we developed a reproducible mouse PLT unit analogous to human PLT units, with a maximum storage time of 1 day for an “old” unit. Fresh and 1-day stored transfused PLTs were found in clots after tail transection. With modifications and different storage conditions, our mouse PLT model can be adapted to reflect clinical transfusion scenarios ultimately to improve patient PLT transfusions.

BACKGROUND:Washing red blood cell (RBC) units mitigates severe allergic transfusion reactions. However, washing reduces the time to expiration and the effective dose. Automated washing is time- and labor-intensive. A shortage of cell processor tubing sets prompted review of medical necessity for washed RBC for patients previously thought to require washing.STUDY DESIGN AND METHODS:A single-center, retrospective study investigated discontinuing wash RBC protocols in chronically transfused adults. In select patients with prior requirements for washing, due to a history of allergic transfusion reactions, trials of unwashed transfusions were performed. Patient demographic, clinical, laboratory, and transfusion data were compiled. The per-unit washing cost was the sum of the tubing set, saline, and technical labor costs.RESULTS:Fifteen patients (median age 34 years interquartile range [IQR] 23-53 years, 46.7% female) were evaluated. These patients had been transfused with a median of 531 washed RBC units (IQR 244-1066) per patient over 12 years (IQR 5-18 years), most commonly for recurrent, non-severe allergic reactions. There were no transfusion reactions with unwashed RBCs aside from one patient with one episode of pruritus and another with recurrent pruritus, which was typical even with washed RBC. We decreased the mean number of washed RBC units per month by 72.9% (104 ± 10 vs. 28.2 ± 25.2; p < .0001) and saved US $100.25 per RBC unit.CONCLUSION:Washing of RBCs may be safely reconsidered in chronically transfused patients without a history of anaphylaxis. Washing should be implemented judiciously due to potential lack of necessity and logistical/operational challenges.

TransfusionVolume 63, Issue S5 p. 55A-55A SUPPLEMENT ARTICLE OA2-AM23-MN-12 | Quality of Platelet Aliquots Prepared as a Contingency Measure for Inventory Shortages K. Forsythe, K. Forsythe Greater Baltimore Medical CenterSearch for more papers by this authorH. Rai, H. Rai Johns Hopkins University School of MedicineSearch for more papers by this authorH. Smetana, H. Smetana Johns Hopkins HospitalSearch for more papers by this authorM. Neally, M. Neally Johns Hopkins HospitalSearch for more papers by this authorC. Marshall, C. Marshall Johns Hopkins HospitalSearch for more papers by this authorI. Francischetti, I. Francischetti Johns Hopkins University School of MedicineSearch for more papers by this authorE. Bloch, E. Bloch Johns Hopkins University School of MedicineSearch for more papers by this authorA. Tobian, A. Tobian Johns Hopkins UniversitySearch for more papers by this authorE. Crowe, E. Crowe Department of Pathology, Johns Hopkins University School of MedicineSearch for more papers by this author K. Forsythe, K. Forsythe Greater Baltimore Medical CenterSearch for more papers by this authorH. Rai, H. Rai Johns Hopkins University School of MedicineSearch for more papers by this authorH. Smetana, H. Smetana Johns Hopkins HospitalSearch for more papers by this authorM. Neally, M. Neally Johns Hopkins HospitalSearch for more papers by this authorC. Marshall, C. Marshall Johns Hopkins HospitalSearch for more papers by this authorI. Francischetti, I. Francischetti Johns Hopkins University School of MedicineSearch for more papers by this authorE. Bloch, E. Bloch Johns Hopkins University School of MedicineSearch for more papers by this authorA. Tobian, A. Tobian Johns Hopkins UniversitySearch for more papers by this authorE. Crowe, E. Crowe Department of Pathology, Johns Hopkins University School of MedicineSearch for more papers by this author First published: 12 October 2023 https://doi.org/10.1111/trf.57_17554Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onEmailFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume63, IssueS5October 2023Pages 55A-55A RelatedInformation

BACKGROUND:COVID-19 convalescent plasma (CCP) is an important therapeutic option for outpatients at high risk of hospitalization from SARS-CoV-2 infection. We assessed the safety of outpatient CCP transfusions administered during clinical trials.STUDY DESIGN AND METHODS:We analyzed data pertaining to transfusion-related reactions from two randomized controlled trials in the U.S. that evaluated the efficacy of CCP versus control plasma in various ambulatory settings. Multivariable logistic regression was used to assess whether CCP was associated with transfusion reactions, after adjusting for potential confounders.RESULTS:The combined study reported 79/1351 (5.9%) adverse events during the transfusion visit, with the majority 62/1351 (4.6%) characterized by mild, allergic-type findings of urticaria, and/or pruritus consistent with minor allergic transfusion reactions; the other reported events were attributed to the patients' underlying disease, COVID-19, or vasovagal in nature. We found no difference in the likelihood of allergic transfusion reactions between those receiving CCP versus control plasma (adjusted odds ratio [AOR], 0.75; 95% CI, 0.43-1.31). Risk of urticaria and/or pruritus increased with a pre-existing diagnosis of asthma (AOR, 2.33; 95% CI, 1.16-4.67). We did not observe any CCP-attributed antibody disease enhancement in participants with COVID-19 or increased risk of infection. There were no life-threatening severe transfusion reactions and no patients required hospitalization related to transfusion-associated complications.DISCUSSION:Outpatient plasma administration was safely performed for nearly 1400 participants. CCP is a safe therapeutic option for outpatients at risk of hospitalization from COVID-19.

BackgroundPolyclonal convalescent plasma may be obtained from donors who have recovered from coronavirus disease 2019 (Covid-19). The efficacy of this plasma in preventing serious complications in outpatients with recent-onset Covid-19 is uncertain.MethodsIn this multicenter, double-blind, randomized, controlled trial, we evaluated the efficacy and safety of Covid-19 convalescent plasma, as compared with control plasma, in symptomatic adults (>= 18 years of age) who had tested positive for severe acute respiratory syndrome coronavirus 2, regardless of their risk factors for disease progression or vaccination status. Participants were enrolled within 8 days after symptom onset and received a transfusion within 1 day after randomization. The primary outcome was Covid-19-related hospitalization within 28 days after transfusion.ResultsParticipants were enrolled from June 3, 2020, through October 1, 2021. A total of 1225 participants underwent randomization, and 1181 received a transfusion. In the prespecified modified intention-to-treat analysis that included only participants who received a transfusion, the primary outcome occurred in 17 of 592 participants (2.9%) who received convalescent plasma and 37 of 589 participants (6.3%) who received control plasma (absolute risk reduction, 3.4 percentage points; 95% confidence interval, 1.0 to 5.8; P & nbsp;-& nbsp;& nbsp;0.005), which corresponded to a relative risk reduction of 54%. Evidence of efficacy in vaccinated participants cannot be inferred from these data because 53 of the 54 participants with Covid-19 who were hospitalized were unvaccinated and 1 participant was partially vaccinated. A total of 16 grade 3 or 4 adverse events (7 in the convalescent-plasma group and 9 in the control-plasma group) occurred in participants who were not hospitalized.ConclusionsIn participants with Covid-19, most of whom were unvaccinated, the administration of convalescent plasma within 9 days after the onset of symptoms reduced the risk of disease progression leading to hospitalization. (Funded by the Department of Defense and others; CSSC-004 ClinicalTrials.gov number, NCT04373460.)

Convalescent plasma, collected from donors who have recovered from a pathogen of interest, has been used to treat infectious diseases, particularly in times of outbreak, when alternative therapies were unavailable. The COVID-19 pandemic revived interest in the use of convalescent plasma. Large observational studies and clinical trials that were executed during the pandemic provided insight into how to use convalescent plasma, whereby high levels of antibodies against the pathogen of interest and administration early within the time course of the disease are critical for optimal therapeutic effect. Several studies have shown outpatient administration of COVID-19 convalescent plasma (CCP) to be both safe and effective, preventing clinical progression in patients when administered within the first week of COVID-19. The United States Food and Drug Administration expanded its emergency use authorization (EUA) to allow for the administration of CCP in an outpatient setting in December 2021, at least for immunocompromised patients or those on immunosuppressive therapy. Outpatient transfusion of CCP and infusion of monoclonal antibody therapies for a highly transmissible infectious disease introduces nuanced challenges related to infection prevention. Drawing on our experiences with the clinical and research use of CCP, we describe the logistical considerations and workflow spanning procurement of qualified products, infrastructure, staffing, transfusion, and associated management of adverse events. The purpose of this description is to facilitate the efforts of others intent on establishing outpatient transfusion programs for CCP and other antibody-based therapies.

Convalescent plasma, collected from donors who have recovered from a pathogen of interest, has been used to treat infectious diseases, particularly in times of outbreak, when alternative therapies were unavailable. The COVID-19 pandemic revived interest in the use of convalescent plasma. Large observational studies and clinical trials that were executed during the pandemic provided insight into how to use convalescent plasma, whereby high levels of antibodies against the pathogen of interest and administration early within the time course of the disease are critical for optimal therapeutic effect. Several studies have shown outpatient administration of COVID-19 convalescent plasma (CCP) to be both safe and effective, preventing clinical progression in patients when administered within the first week of COVID-19. The United States Food and Drug Administration expanded its emergency use authorization (EUA) to allow for the administration of CCP in an outpatient setting in December 2021, at least for immunocompromised patients or those on immunosuppressive therapy. Outpatient transfusion of CCP and infusion of monoclonal antibody therapies for a highly transmissible infectious disease introduces nuanced challenges related to infection prevention. Drawing on our experiences with the clinical and research use of CCP, we describe the logistical considerations and workflow spanning procurement of qualified products, infrastructure, staffing, transfusion, and associated management of adverse events. The purpose of this description is to facilitate the efforts of others intent on establishing outpatient transfusion programs for CCP and other antibody-based therapies.

ABSTRACTBACKGROUNDThe efficacy of polyclonal high titer convalescent plasma to prevent serious complications of COVID-19 in outpatients with recent onset of illness is uncertain.METHODSThis multicenter, double-blind randomized controlled trial compared the efficacy and safety of SARS-CoV-2 high titer convalescent plasma to placebo control plasma in symptomatic adults ≥18 years positive for SARS-CoV-2 regardless of risk factors for disease progression or vaccine status. Participants with symptom onset within 8 days were enrolled, then transfused within the subsequent day. The measured primary outcome was COVID-19-related hospitalization within 28 days of plasma transfusion. The enrollment period was June 3, 2020 to October 1, 2021.RESULTSA total of 1225 participants were randomized and 1181 transfused. In the pre-specified modified intention-to-treat analysis that excluded those not transfused, the primary endpoint occurred in 37 of 589 (6.3%) who received placebo control plasma and in 17 of 592 (2.9%) participants who received convalescent plasma (relative risk, 0.46; one-sided 95% upper bound confidence interval 0.733; P=0.004) corresponding to a 54% risk reduction. Examination with a model adjusting for covariates related to the outcome did not change the conclusions.CONCLUSIONEarly administration of high titer SARS-CoV-2 convalescent plasma reduced outpatient hospitalizations by more than 50%. High titer convalescent plasma is an effective early outpatient COVID-19 treatment with the advantages of low cost, wide availability, and rapid resilience to variant emergence from viral genetic drift in the face of a changing pandemic.Trial RegistrationClinicalTrials.gov number, NCT04373460.

Background/Case Studies: Platelets are critical to the management of diverse patient populations. As a scarce resource, they are also a high-cost blood component. Allied with their short shelf life and unpredictable usage, this risks wastage. We sought to reduce wastage (i.e., outdating) without imposing platelet shortages through refined distribution of platelets across our health system. Study Design/Methods: Platelets that were approaching expiration (i.e., morning of Day 5) at two community hospital-based blood banks were transferred to the largest of the three affiliates, a large tertiary care medical center. The approach extended over three years;initially it was adopted between two hospitals, and a third hospital was later included. Data were collected and recorded about the source of the platelet units, the number sent, the date received, and whether they were transfused or discarded/outdated. Results/Findings: Of the 596 units that were transferred to the main hospital over the study observation period, 561 units (94.1%) were transfused. Only 35 units (5.9%) were discarded. Given the approximate cost of a unit of platelets (i.e., US$ 500-700), this approach avoided wastage of around US$ 100,000-140,000 per year. Further, this approach improved emergency preparedness at the smaller hospitals given the ability to maintain larger platelet inventories for unexpected emergencies without risking waste. The model's success prompted the addition of a third hospital (all within a 20-mile radius). Conclusions: Given expansion of healthcare systems, careful inventory management of blood components such as platelets can optimize platelet availability while minimizing wastage. This gained impetus early during the COVID-19 pandemic when a host of challenges contributed to uncertainty in the blood supply necessitating conservation and/or optimization of extant blood inventories.

Background and Objectives ABO blood group may affect risk of SARS-CoV-2 infection and/or severity of COVID-19. We sought to determine whether IgG, IgA and neutralizing antibody (nAb) to SARS-CoV-2 vary by ABO blood group. Materials and Methods Among eligible convalescent plasma donors, ABO blood group was determined via agglutination of reagent A1 and B cells, IgA and IgG were quantified using the Euroimmun anti-SARS-CoV-2 ELISA, and nAb titres were quantified using a microneutralization assay. Differences in titre distribution were examined by ABO blood group using non-parametric Kruskal-Wallis tests. Adjusted prevalence ratios (aPR) of high nAb titre (>= 1:160) were estimated by blood group using multivariable modified Poisson regression models that adjusted for age, sex, hospitalization status and time since SARS-CoV-2 diagnosis. Results Of the 202 potential donors, 65 (32%) were blood group A, 39 (19%) were group B, 13 (6%) were group AB, and 85 (42%) were group O. Distribution of nAb titres significantly differed by ABO blood group, whereas there were no significant differences in anti-spike IgA or anti-spike IgG titres by ABO blood group. There were significantly more individuals with high nAb titre (>= 1:160) among those with blood group B, compared with group O (aPR = 1 center dot 9 [95%CI = 1 center dot 1-3 center dot 3], P = 0 center dot 029). Fewer individuals had a high nAb titre among those with blood group A, compared with group B (aPR = 0 center dot 6 [95%CI = 0 center dot 4-1 center dot 0], P = 0 center dot 053). Conclusion Eligible CCP donors with blood group B may have relatively higher neutralizing antibody titres. Additional studies evaluating ABO blood groups and antibody titres that incorporate COVID-19 severity are needed.

Herstine, Erin; Simonds, Grant; Kitlas, Jessica; Strudwick, Kurt; Marshall, Christi; Gehrie, Eric; McMillan, Kristen Nelson Author Information

In 2019, the United States Food and Drug Administration published its final recommendations to mitigate bacterial contamination of platelets. We sought to evaluate our secondary bacterial culture (SBC) strategy in light of those recommendations.

Herstine, Erin1; Gehrie, Eric1; Marshall, Christi2; Blakemore, Karin1; Hibino, Narutoshi1; Vricella, Luca3; McMillan, Kristen Nelson3 Author Information

BACKGROUND:Isohemagglutinins (anti-A and anti-B) mediate hemolytic transfusion reactions, antibody-mediated rejection of solid-organ transplants, and delayed engraftment after stem cell transplant. However, quantification of isohemagglutinins is often labor intensive and operator dependent, limiting availability and interfacility comparisons. We evaluated an automated, solid-phase and agglutination-based antibody titer platform versus manual gel testing.STUDY DESIGN AND METHODS:Plasma samples were obtained from 54 randomly selected patients. Titers were determined by our laboratory's standard assay (manual dilution followed by manual gel testing) and were compared to results obtained on a fully automated blood bank analyzer (Galileo NEO, Immucor). The analyzer determined immunoglobulin G (IgG) antibodies using solid-phase and immunoglobulin M (IgM) antibodies by direct hemagglutination.RESULTS:Isohemagglutinin titers obtained by manual gel versus the automated assay generally (>80%) agreed within one doubling dilution, and always (100%) agreed within two dilutions. Among O samples, the gel titer and the highest titer obtained with the automated assay (either IgG or IgM) were similar in paired, nonparametric analysis (p = 0.06 for anti-A; p = 0.13 for anti-B). Gel titers from group A and group B patients were slightly higher than the highest titer obtained using the automated assay (p = 0.04 for group A; p = 0.009 for group B), although these differences were within the accepted error of measurement.CONCLUSION:Manual and automated methodologies yielded similar isohemagglutinin titers. Separate quantification of IgM and IgG isohemagglutinins via automated titration may yield additional insight into hemolysis, graft survival after ABO-incompatible transplantation, and red blood cell engraftment after ABO-incompatible stem cell transplant.

BACKGROUNDBacterial contamination of platelets remains the leading infectious risk from blood transfusion. Pathogen reduction (PR), point-of-release testing (PORt), and secondary bacterial culture (SBC) have been proposed as alternative risk control strategies, but a comprehensive financial comparison has not been conducted. STUDY DESIGN AND METHODSA Markov-based decision tree was constructed to model the financial and clinical impact of PR, PORt, and SBC, as well as a baseline strategy involving routine testing only. Hospitals were assumed to acquire leukoreduced apheresis platelets on Day 3 after collection, and, in the base case analysis, expiration would occur at the end of Day 5 (PR and SBC) or 7 (PORt). Monte Carlo simulations assessed the direct medical costs for platelet acquisition, testing, transfusion, and possible complications. Input parameters, including test sensitivity and specificity, were drawn from existing literature, and costs (2018 US dollars) were based on a hospital perspective. RESULTSThe total costs per unit acquired by the hospital under the baseline strategy, PR, PORt, and SBC were $651.45, $827.82, $686.33, and $668.50, respectively. All risk-reduction strategies decreased septic transfusion reactions and associated expenses, with the greatest reductions from PR. PR would add $191.09 in per-unit acquisition costs, whereas PORt and SBC would increase per-unit testing costs by $31.79 and $17.26, respectively. Financial outcomes were sensitive to platelet dating; allowing 7-day storage with SBC would lead to a cost savings of $12.41 per transfused unit. Results remained robust in probabilistic sensitivity analyses. CONCLUSIONSAll three strategies are viable approaches to reducing bacterially contaminated platelet transfusions, although SBC is likely to be the cheapest overall.