The importance of ABO in platelet refractoriness, an often overlooked option.

ABO-non-identical (ni) platelets provide less of an increase in platelet count and may increase the length of patient transfusions. The paper by Han and Badami showed that ABO-ni platelets may be a risk factor for immune platelet transfusion refractoriness. Commentary on: Han et al. ABO non-identical platelet transfusions, immune platelet refractoriness and platelet support. Br J Haematol 2024;204:2097-2102.

Is it time for the death knell of single-unit plasma?

BACKGROUND AND OBJECTIVES: A plasma transfusion dose should be weight-based (10-20 mL/kg), which equates to three to four units in an average-sized adult; therefore, the transfusion of single units under most circumstances is sub-therapeutic. MATERIALS AND METHODS: This retrospective observational study examined the prevalence of single-unit plasma transfusion in adults within a 12-hospital system from 1 January 2018, to 31 December 2019. RESULTS: During the study period, 5791 patients received plasma transfusions. The overall prevalence of single-unit plasma was 17.1% for 988 patients. The majority, 3047 (52.6%), occurred at one hospital, 2132 (36.9%) among five hospitals and 612 (10.7%) at the remaining six hospitals. Cardiac and gastrointestinal (GI)/transplant transfused 2707 (46.8%), combined respiratory, neurological, orthopaedic and congenital/dermatology/other comprised 2133 (36.9%) of the six hospitals that transfused less than 200 patients, four (66.7%) transfused single units above the overall prevalence. CONCLUSION: In this hospital system, more than one in six patients received a transfusion of a single plasma unit. Six of the 12 hospitals had 89.5% of the patients who were transfused plasma. Six service lines transfused 83.7% of all patients receiving plasma. Hospitals that infrequently transfused plasma were more likely to under-dose.

Patient blood management using dedicated personnel in the operating room-you get what you pay for.

A patient blood management (PBM) strategy can be applied to the process of intraoperative cell salvage for re-infusion during surgery. Stoneham et al. describe an effective PBM strategy applied to abdominal aortic aneurysm repair and emphasise the importance of a qualified and experienced intraoperative cell salvage practitioner to improve the safety and effectiveness of the approach. Commentary on: Stoneham et al. Intraoperative cell salvage using swab wash and serial thromboelastography in elective abdominal aortic aneurysm surgery involving massive blood loss. Br J Haematol 2023;200:652-659.

The science or not behind deferrals of blood donors with a history of cancer.

BACKGROUND: In the United States (US), each blood center's medical director sets policy for donors with a cancer history. STUDY DESIGN AND METHODS: A subgroup of America's Blood Centers' (ABC) Scientific, Medical, and Technical Committee developed a survey to measure the determination of eligibility, policies for deferral and/or lookback when a donor reports a current diagnosis or history of cancer. A 31-question survey was sent to 47 ABC blood centers in North America via email. Survey results were compiled and literature evaluating the risk of cancer transmission by transfusion was reviewed. RESULTS: Responses were received from 37 centers (79%). Donors with a history of carcinoma or sarcoma who had completed treatment were accepted at 73% of centers with no further deferral. Donors with a history of leukemia or lymphoma were permanently deferred at 76% of centers. Donors with a myelodysplastic or myeloproliferative syndrome were deferred permanently at 86% of centers. Handling of donors with high white cell counts varied. Donors with cancer not in active treatment (i.e., prostate cancer) were subject to various deferrals. Center response to post-donation reports of cancer vary widely. Literature review yielded no evidence of transfusion-transmitted cancer. CONCLUSION: Cancer deferral policies vary widely among blood centers, and are not generally based on evidence, but on some aspect of the precautionary principle. As the donor population ages and so becomes more at risk of cancer, this approach may further reduce the available donor pool.

How do I manage a blood product shortage?

BACKGROUND: The demand for blood products sometimes exceeds the available inventory. Blood product inventories are dependent upon the availability of donors, supplies and reagents, and collection staff. During prolonged extreme shortages, blood centers and transfusion services must alter practices to meet the needs of patients. STUDY DESIGN AND METHODS: The Association for the Advancement of Blood and Biotherapies Donor and Blood Component Management Subsection compiled some strategies from its blood center and hospital transfusion service members that could be implemented during blood product shortages. RESULTS: Some strategies that blood centers could use to increase their available inventories include increasing donor recruitment efforts, using alternate types of collection kits, manufacturing low-yield apheresis-derived platelets and/or whole blood-derived platelets, using cold-stored platelets, transferring inventory internally among centers of the same enterprise, using frozen inventory, decreasing standing order quantities, prioritizing allocation to certain patient populations, filling partial orders, and educating customers and blood center staff. Transfusion service strategies that could be implemented to maximize the use of the limited available inventory include increasing patient blood management efforts, using split units, finding alternate blood suppliers, trading blood products with other hospital transfusion services, developing a patient priority list, assembling a hospital committee to decide on triaging priorities, using expired products in extreme situations, and accepting nonconforming products after performing safety checks. DISCUSSION: Blood centers and transfusion services must choose the appropriate strategies to implement based on their needs.

Patient blood management: Myths and facts about red blood cell transfusions.

Transfusion medicine resembles all of medicine in that expert opinion predominates because hard data on clinical outcomes from randomized controlled trials and high quality observational data are simply unavailable. Indeed, some of the first trials evaluating important outcomes are barely two decades old. Patient blood management (PBM) depends on high quality data for assisting clinicians in making clinical decisions. In this review, we focus on several red blood cell (RBC) transfusion practices that new data suggest need reconsideration. The practices that may need revision include transfusion for iron deficiency anaemia, except in life threatening situations, toleration of anaemia as a largely benign condition and use of haemoglobin/haematocrit as primary indications for RBC transfusion, as opposed to adjuncts to clinical judgement. In addition, the long-standing notion that the minimum transfusion should be two units needs to be abandoned due to the danger to patients and a lack of clinical evidence of benefit. Finally, the difference in indications for leucoreduction versus irradiation needs to be understood by all practitioners. PBM is one of the strategies for managing anaemia and bleeding that holds great promise for patients, and transfusion is only one facet of the bundle of practices.

Cold stored platelets - Increasing understanding and acceptance.

Platelet transfusions decreased the risk of morbidity and mortality secondary to thrombocytopenia. This therapy not only ameliorates platelet loss in bleeding patients,but also those with acquired dysfunction of platelets. The current standard of practice worldwide is to provide room temperature platelets (RTPs); however, there are many disadvantages to the use of RTPs such that alternative approaches have been explored. One potential approach is the integration and use of cold stored platelets (CSP), which are platelets stored at 1-6 °C, in clinical settings. CSP research studies show equivalent hemostasis and platelet dysfunction restoration compared to RTPs. In addition, publications have demonstrated advantages of CSP such as reduced bacterial contamination and wastage. Despite its benefits, the production of CSP by blood centers (BCs) and uptake and use of CSP by hospitals has remained relatively low. This review highlights the rationale for CSP production and strategies for overcoming the implementation challenges faced by BCs based on a literature review.Experiences of Consortium for Blood Availability members to integrate CSP in their BCs and clinical practices by providing variance applications are reviewed in this paper. Also, demonstrated in this manuscript are the current indications and opportunities for CSP utilization by healthcare providers.

Beyond COVID-19 and lessons learned in the United States.

The COVID-19 pandemic severely tested the resilience of the US blood supply with wild fluctuations in blood donation and utilisation rates as community donation opportunities ebbed and hospitals post-poned elective surgery. Key stakeholders in transfusion services, blood centres, supply chains and manufacturers reviewed their experiences during the SARS-CoV-2 pandemic as well as available literature to describe successes, opportunities for improvement and lessons learned. The blood community found itself in uncharted territory responding to restriction of its access to donors (approximately 20% decrease) and some supplies; environmental adjustments to address staff and donor concerns about coronavirus transmission; and the development of a new product (COVID-19 convalescent plasma [CCP]). In assuring that the needs of the patients were paramount, the donation process was safe, that clinicians had access to CCP, and vendor relationships aligned, the blood banking community relearned its primary focus: improving patient outcomes.

CMV screening of group-specific orders-good stewardship of the blood supply.

BACKGROUND: In addition to antigen-negative red blood cells (RBC), Immunohematology Reference Laboratories (IRL) must provide RBCs that are cytomegalovirus (CMV) seronegative. Due to high percentage of CMV seropositive individuals, it is challenging to find CMV and antigen-negative RBC. The IRL selects predominantly group O donors tested for CMV, and these RBC are sometimes needed to fill orders for nongroup O patients. This study evaluated units sent that were out of group to fulfill CMV-seronegative requests. STUDY DESIGN AND METHODS: Requests for CMV-seronegative and antigen-negative RBCs were divided into Period 1 (January 1, 2019-February 29, 2020) before intervention and Period 2 (March 1, 2020-May 31, 2020) post intervention. ABO Rh units requested were compared to ABO Rh units provided. RESULTS: Period 1: 537 CMV-seronegative RBC units were provided. 99/188(52.66%) B-positive requests were fulfilled using O RBCs. 58/504 (11.51%) of D-negative units were sent to D-positive patients. Period 2: 119 CMV-seronegative RBC units were provided. 18/51 (35.29%) B positive requests were fulfilled using O RBCs. Only 7/113 (6.19%) D-negative units were sent to D-positive patients. DISCUSSION: For 239/656 (36.43%) CMV-seronegative antigen orders requested for B-positive patients, more than half of these orders were filled with O RBCs. To decrease group O usage for nongroup O patients, the IRL practice has changed to increase CMV testing for group B donors. Since the change in algorithm, there was a 17.37% decrease group O usage for group B patients.

How do we obtain and maintain patient blood management certification?

BACKGROUND: The creation of a patient blood management (PBM) certification program by The Joint Commission (TJC) and Association for the Advancement of Blood and Biotherapies (AABB) provides validation of an existing PBM program. MATERIALS AND METHODS: A team of subject matter experts in PBM formed a working group to develop a structured approach to guide PBM programs through the PBM certification. Program challenges and metrics were reviewed. RESULTS: Initial steps to establishing PBM certification include a multidisciplinary working group and hospital administration buy-in. Development of policies and procedures individualized to the facility will standardize practice. An institutional transfusion committee can provide PBM oversight including enforcing compliance. Using resources such as TJC and AABB standards and tools including electronic medical records (EMR) can track and trend hospital PBM performance and identify improvement opportunities. A gap analysis tool helps implementation. Challenges might include maintaining a PBM program during a merger, slow responsiveness of information systems (IS) to requests, PBM education for both the Transfusion Safety Officer (TSO) and hospital staff with constant turnover. Available metrics from one hospital system showed good compliance with transfusion thresholds (average all products: 97.9%, 2019, 2020). In 2020, through educational efforts the cost savings were $124,856.70 compared to 2019. Regarding single unit transfusion of RBCs, this was 62.25% (2019), 63.75% (2020), 72.00% (2021), and surpassed the target goal of 60%. CONCLUSIONS: Obtaining PBM certification highlights the success of an institution's PBM program. Facilities that have achieved PBM certification have seen significant reductions in transfusions and considerable cost savings.

Acquired platelet storage container leaks and contamination with environmental bacteria: A preventable cause of bacterial sepsis.

BACKGROUND: Apheresis platelets (AP) may be contaminated by environmental bacteria via container defects acquired during processing, transport, storage, or transfusion, as highlighted by a recent series of septic reactions related to Acinetobacter spp. and other bacterial strains. STUDY DESIGN AND METHODS: The frequency and nature of acquired container defect reports to one manufacturer were evaluated from January 2019 to July 2020. The published incidence of contamination and sepsis due to environmental bacteria with culture screened AP in the United States was reviewed for the period of 2010-2019. RESULTS: Review of a manufacturers' records showed 23 US reports of leaks involving 24 containers attributed to postmanufacturing damage, at a rate of 44 per million distributed storage containers. Analysis of returned containers showed evidence of scratches, impressions, and/or piercings. Literature review of US hemovigilance data revealed that environmental bacteria comprised 7% of confirmed positive primary bacterial culture screens, were responsible for 14%-16% of reported septic, and 8 of 28 (29%) fatal reactions with bacterial-culture screened AP. Sepsis cases have been reported with culture screened, point-of-issue (POI) tested, or pathogen-reduced AP. DISCUSSION: Environmental contamination of AP is rare but can cause sepsis. Container damage provides a pathway for contamination after culture screening, POI bacteria testing, or pathogen reduction. Blood collectors and transfusion services should have procedures to ensure proper inspection, handling, storage, and transport of AP to avoid damage and should enhance efforts to detect defects prior to release and to eliminate bacteria from all contacting surfaces to minimize the risk of contamination.

Early and out-of-hospital use of COVID-19 convalescent plasma: An international assessment of utilization and feasibility.

BACKGROUND AND OBJECTIVES: The use of coronavirus disease 2019 (COVID-19) convalescent plasma (CCP) in the treatment of patients with severe acute respiratory syndrome-2 infection has been controversial. Early administration of CCP before hospital admission offers a potential advantage. This manuscript summarizes current trials of early use of CCP and explores the feasibility of this approach in different countries. MATERIALS AND METHODS: A questionnaire was distributed to the International Society of Blood Transfusion (ISBT) CCP working group. We recorded respondents' input on existing trials on early/outpatient CCP and out-of-hospital (OOH)/home transfusion (HT) practices in their countries and feedback on challenges in initiating home CCP infusion programmes. In addition, details of existing trials registered on clinicaltrials.gov were summarized. RESULTS: A total of 31 country representatives participated. Early/OOH CCP transfusion studies were reported in the United States, the Netherlands, Spain and Brazil. There were a total of six published and five ongoing trials on the prophylactic and therapeutic early use of CCP. HT was practised in Australia, the UK, Belgium, France, Japan, Nigeria, the Netherlands, Spain, Italy, Norway, the United States and some provinces in Canada. Thirty-four representatives indicated a lack of OOH CCP or HT in their institutions and countries. Barriers to implementation of OOH/HT included existing legislation, lack of policies pertaining to outpatient transfusion, and associated logistical challenges, including lack of staffing and resources. CONCLUSION: Early administration of CCP remains a potential option in COVID-19 management in countries with existing OOH/HT programmes. Legislation and regulatory bodies should consider OOH/HT practice for transfusion in future pandemics.

Critical conversations on patient blood management with clinical colleagues.

Although a subspecialty-trained transfusion medicine (TM) physician brings value to the clinical bedside, hospital transfusion service oversight often falls under the responsibility of pathologists primarily focused on surgical pathology. Yet, pathologists who lack TM fellowship training may not be quite as confident in their role as the TM physician in-charge, especially when the need to communicate with another clinician arises. Given that blood is a resource subject to frequent shortages, there is a need for constant monitoring of blood utilization such that those responsible for transfusion service oversight need to handle challenging clinical interactions when transfusion guidelines are breeched. Generally, the average pathologist is more knowledgeable regarding blood component therapy than other clinician. Yet, disagreements concerning patient transfusion management can arise, in spite of established evidence-based hospital transfusion guidelines. Since authoritative fact stating is not likely to be effective in changing the entrenched practices, pathologists must engage in strategies that will develop meaningful working relationships with their clinical colleagues. Such strategies include being a visible part of direct patient care, such as attendance at patient rounds or provision of mini-consultations by phone regarding transfusion management. Inviting clinicians to attend the hospital transfusion committee meetings and scheduling educational grand rounds are also useful strategies. Clinicians may be more receptive to blood conservation during times of shortages if open communication is established, particularly if hospital leadership is involved in urgent crisis messaging to the clinicians and other hospital staff involved in patient care.

Transfusion therapy of neonatal and paediatric patients: They are not just little adults.

Patient blood management (PBM) strategies are needed in the neonate and paediatric population, given that haemoglobin thresholds used are often higher than recommended by evidence, with exposure of children to potential complications without meaningful benefit. A literature review was performed on the following topics: evidence-based transfusions of blood components and pharmaceutical agents. Other topics reviewed included perioperative coagulation assessment and perioperative PBM. The Transfusion and Anaemia Expertise Initiative (TAXI) consortium published a consensus statement addressing haemoglobin (Hb) transfusion threshold in multiple subsets of patients. A multicentre trial (PlaNeT-2) reported a higher risk of bleeding and death or serious new bleeding among infants who received platelet transfusion at a higher (50 000/µl) compared to a lower (25 000/µl) threshold. Recent data support the use of a restrictive transfusion threshold of 25 000/µl for prophylactic platelet transfusions in preterm neonates. The TAXI-CAB consortium mentioned that in critically ill paediatric patients undergoing invasive procedures outside of the operating room, platelet transfusion might be considered when the platelet count is less than or equal to 20 000/µl and there is no benefit of platelet transfusion when the platelet count is more than 50 000/µl. There are limited controlled studies in paediatric and neonatal population regarding plasma transfusion. Blood conservation strategies to minimise allogenic blood exposure are essential to positive patient outcomes neonatal and paediatric transfusion practices have changed significantly in recent years since randomised controlled trials were published to guide practice. Additional studies are needed in order to provide practice change recommendations.

The effect of COVID-19 on blood donation habits.

BACKGROUND: Blood centers (BCs) rely on schools and businesses. Shelter-in-place orders closed them. This study determined how COVID-19 affected donation habits. STUDY DESIGN AND METHODS: Two periods were reviewed (May 1 through June 30, 2018 vs 2019 [control] and 2019 vs 2020 [study-COVID period]). These donations were reviewed: first-time, repeat (donation ≤ 2 years), and lapsed (no donation > 2 years); sex; age; ethnicity; and ABO blood groups at high school and college drives. Testing all donors for SARS-CoV-2 antibodies started May 18, 2020. RESULTS: In the study period donations significantly increased (control P = .683, study P ≤ .0001) and comparing sex (control male P = .716, female P = .657; study male P = .004, female P ≤ .0001). In the study period there was a significant decrease in Hispanic (P = .001) and African American (P < .0001) donations also seen among high school and college drives and an increase in Caucasian (P < .0001) donations. There was a significant increase in first-time (P < .0001) and lapsed donors (P < .0001) in the study period vs control (first-time P = .087, lapsed P = .308) and a significant decrease in donors not more than 30 years (study 16-20 P < .0001, 21-30 P < .0001). There was a significant increase in all blood types in the study period (P < .0001) and in donations after implementation of SARS-CoV-2 antibody testing (P = .001). CONCLUSIONS: Significant changes occurred in donation habits in the study vs the control periods. These included increased total donations, comparing sexes, first-time and lapsed donors, all blood types, and Caucasian donations. Significant decreases were seen in Hispanic and African American donations and those not more than 30 years old.

Maintaining adequate donations and a sustainable blood supply: Lessons learned.

BACKGROUND: The availability of a safe blood supply is a key component of transfusion medicine. A decade of decreased blood use, decreased payment for products, and a dwindling donor base have placed the sustainability of the US blood supply at risk. STUDY DESIGN AND METHODS: A literature review was performed for blood center (BC) and hospital disaster management, chronically transfusion-dependent diseases, and appropriate use of group O-negative red blood cells (RBCs), and the Choosing Wisely campaign. The aim was to identify current practice and to make recommendations for BC and hospital actions. RESULTS: While BCs are better prepared to handle disasters than after the 9/11 attacks, messaging to the public remains difficult, as donors often do not realize that blood transfused during a disaster was likely collected before the event. BCs and transfusion services should participate in drafting disaster response plans. Hospitals should maintain inventories adequate for patients in the event supply is disrupted. Providing specialty products for transfusion-dependent patients can strain collections, lead to increased use of group O RBCs, and create logistical inventory challenges for hospitals. The AABB Choosing Wisely initiative addresses overuse of blood components to optimally use this precious resource. Group O-negative RBCs should be transfused only to patients who truly need them. CONCLUSIONS: Collecting and maintaining a blood supply robust enough to handle disasters and transfusion-dependent patients in need of specialty products is challenging. Collaboration of all parties should help to optimize resources, ensure appropriate collections, improve patient care, and ultimately result in a robust, sustainable blood supply.

Buffy coat platelets coming to America: Are we ready?

BACKGROUND: Buffy coat (BC) platelets (PLTs) have been used globally for many years. In 2004 Canadian Blood Services (CBS) made the decision to transition from PLT-rich plasma (PRP) to BC PLTs. We reviewed the benefits and manufacture process of BC and the implementation challenges involved. STUDY DESIGN AND METHODS: A literature review was performed in the following areas: BC efficacy, donor population shifts, production and good stewardship of PLTs, logistic considerations with overnight holds, advantages of the overnight hold, the CBS experience, licensure and standards, and changes needed to produce BC PLTs in the United States. The aim was to analyze current practice and identify possible actions for blood centers and hospitals. RESULTS: Implementation of BC would offer an additional source of PLTs to address the growing elderly population and the declining apheresis donor base. Substantial logistic, operational, and financial benefits were seen when CBS transitioned to BC with overnight hold. CONCLUSIONS: Buffy coat blood products are widely used throughout the world. Recent conversion from PRP to BC by CBS showed that conversion can be accomplished with planning, communication, and partnership from all stakeholders. In conclusion, BC PLTs are worth serious consideration in the United States, but regulatory barriers in the United States will need to be addressed.

A survey of US hospitals on platelet inventory management, transfusion practice, and platelet availability.

BACKGROUND: A survey of US hospitals was conducted to increase our understanding of the current state of platelet (PLT) practice and supply. The survey captures information on transfusion practice and inventory management, including stock levels, outdate rates, ability to return or transfer PLTs, and low dose PLTs. Notably, the survey also elucidates PLT availability challenges and impact to patient care. STUDY DESIGN AND METHODS: A 27 question online survey was distributed directly to over 995 US hospitals and indirectly through blood centers to many more between September 27 and October 25, 2019. Descriptive statistics were used for respondent characteristics. Bivariate analysis was performed and correlation coefficients, chi square tests, and p values determined statistical significance of relationships between variables. RESULTS: Four hundred and eighty-one hospitals completed the survey of which 21.6%, 53.2%, and 25.2% were characterized as small, medium, and large hospitals, respectively. Some key observations from this survey include: (1) there is an opportunity for greater adherence to evidence-based guidelines; (2) higher outdate rates occur in hospitals stocking less than five PLTs and the ability to return or transfer PLTs lowers outdates; (3) use of low dose apheresis PLTs varies; and (4) decreased PLT availability is commonly reported, especially in hospitals with high usage, and can lead to delays in transfusions or surgeries. CONCLUSION: This survey represents a comprehensive national assessment of inventory management practices and PLT availability challenges in US hospitals. Findings from this survey can be used to guide further research, help shape future guidance for industry, and assist with policy decisions.

The safety of COVID-19 convalescent plasma donation: A multi-institutional donor hemovigilance study.

BACKGROUND: Although the safety and therapeutic efficacy of COVID-19 convalescent plasma (CCP) has been extensively evaluated, the safety of CCP donation has not been explored in a multi-institutional context. STUDY DESIGN AND METHODS: Nine blood collection organizations (BCOs) participated in a multi-institutional donor hemovigilance effort to assess the safety of CCP donation. Donor adverse events (DAEs) were defined according to the Standard for Surveillance of Complications Related to Blood Donation, and severity was assessed using the severity grading tool. Multivariate analysis was performed to determine attributes associated with DAE severity. RESULTS: The overall DAE rate was 37.7 per 1000 donations. Repeat apheresis and apheresis-naïve donors experienced adverse event rates of 19.9 and 49.8 per 1000 donations, respectively. Female donors contributed 51.9% of CCP donations with a DAE rate of 49.4 per 1000 donations. The DAE rate for male donors was 27.4 per 1000 donations. Vasovagal reactions accounted for over half of all reported DAEs (51.1%). After adjustment, volume of CCP donated was associated with vasovagal reaction severity (odds ratio [OR] 6.5, 95% confidence interval [CI] 2.5-17.1). Donor age and donation history were also associated with DAE severity. Considerable differences in DAE types and rates were observed across the participating BCOs despite the use of standardized hemovigilance definitions. CONCLUSION: The safety of CCP donation appears comparable to that of conventional apheresis plasma donation with similar associated risk factors for DAE types and severity.

An international effort and use of social media to save a young girl.

BACKGROUND AND OBJECTIVES: A 2-year-old female with neuroblastoma needed In(b-), E- red blood cells (RBCs). No units were available at the blood centre (BC) nor in the rare donor programme member's inventories. BC's Immunohematology Reference Laboratory (IRL) and its marketing department concentrated on recruiting and testing those donors more likely to be antigen negative based on ethnicity. MATERIALS AND METHODS: The BC's communication plan utilized social and traditional media to assist in the search for In(b-) blood. Media strategies directed donors in the United States (US) and Canada to go to their nearest BC for collection, tagging and testing of units. Two segments from each donation were shipped overnight to the BC's IRL (associated with the patient) for testing. Diluted anti-Inb sera was tested by microtechniques to conserve resources. Additionally, the American Rare Donor Program (ARDP) facilitated the international searches and acted as a liaison to the Food and Drug Administration (FDA). RESULTS: More than 25 000 people responded to the appeal. Seventy-seven BCs submitted segments from 4197 units. Two donors were In(b-) but E+ and thus not compatible with the patient but were submitted to ARDP for future needs. The prevalence of In(b-) units identified in the search was 0·048%. In total, five known In(b-) donors, two from the US and three from international sources, provided units for this patient. CONCLUSION: Social media sparked a viral response to the rare blood need. While a match was not found among the units tested, domestic and international searches were able to meet the patient's blood needs.