Notification and follow-up of blood donors reactive for transfusion-transmitted infections: A narrative review of the literature from India

BACKGROUND AND OBJECTIVES

Notifying blood donors of their reactive status for transfusion-transmitted infections (TTIs) plays a vital role in enabling early diagnosis and management while also preventing these donors from making future donation and transmission of the infectious agent. Given the limited data on donor notification processes in India, a narrative review was conducted to assess the existing notification process and identify areas requiring enhancement.

MATERIALS AND METHODS

We conducted literature searches using PubMed, Google Scholar and Scopus, employing various keywords. The review included data on the year of the study, study design, donor numbers, TTI screening methods, sero-reactive donor confirmation, notification frequency and methods, donor responses, post-test counselling and risk factor assessment.

RESULTS

Out of the 29 identified articles, 16 studies were included in the analysis. Repeat testing for initially reactive results was conducted in nine studies for 24.3% reactive donors. Phone calls were the primary notification method in most studies (8; 50%), with letters sent in cases of no response. Only 12 studies provided data on notified donors, revealing a notification rate of 71.2%. Of all initially reactive donors, 33.3% sought post-test counselling. Data from six studies indicated that 74.3% of responsive donors had identifiable TTI risk factors.

CONCLUSION

Our review revealed significant variability in the notification processes across different studies. To enhance the management of TTI-reactive donor notifications and responses, we recommend the establishment of universal protocols encompassing pre-donation counselling, repeat/confirmatory testing, notification methods and comprehensive follow-up and treatment.

The impact of pre-donation viral markers screening of new blood donors on blood safety

BACKGROUND

The risk of transfusion-transmissible infections (TTIs) remains a concern in transfusion medicine. Since the rate of infection among first-time blood donors is higher than repeated donors, strategies to enhance blood safety can focus on new donors. The aim of the study was to investigate the effect of pre-donation viral screening of new donors on blood safety.

METHODS AND MATERIALS

The pre-donation screening of new donors was implemented in the Kurdistan blood center. In this program, new donors who met the blood donation criteria were informed about the program and only a blood sample was donated for HBs Ag, HCV Ab, and HIV Ab testing. New donors with negative results were invited to donate blood after 12 weeks. A unit of blood was collected from eligible returned donors. Laboratory tests were performed again using the same methods. Finally, the prevalence of confirmed positive TTI results among donated blood in Kurdistan blood center was compared before and after the establishment of program.

RESULTS

During the study, 4,434 new donors were screened for viral markers. A total of 41 new donors (0.92%, 95% CI, 0.007-0.13) had repeatedly reactive results and infection was confirmed in blood sample of 24 donors (0.54%, 95% CI, 0.003-0.008). Overall, 56% of new donors returned for blood donation. Prevalence of confirmed TTIs markers in collected blood units was 0.27% and 0 before and after implementing program, respectively.

CONCLUSIONS

This study indicated that Pre-donation screening can reduce the risk of TTI transmission by identifying infected donors at the pre-donation phase.

Les anémies aiguës et la stratégie transfusionnelle chez les drépanocytaires adultes

Worsening of anemia is very common in sickle cell disease. It is important to investigate specific complications related to sickle cell disease but also other causes of anemia in general. Transfusions or exchange transfusions are major therapeutic options and are frequently used for acute complications of sickle cell disease but also for primary and secondary prevention of some of the chronic complications. The transfusion strategy has been modified since the awareness of post-transfusion hemolysis by taking into account the transfusion risk score. A strong collaboration between the patient's expert center, the Blood center and the patient's hospitalization unit is required to make decisions. © 2023 Société nationale française de médecine interne (SNFMI). Published by Elsevier Masson SAS. All rights reserved.

Battle of the (Chat)Bots: Comparing Large Language Models to Practice Guidelines for Transfusion-Associated Graft-Versus-Host Disease Prevention

Published guidelines and clinical practices vary when defining indications for irradiation of blood components for the prevention of transfusion-associated graft-versus-host disease (TA-GVHD). This study assessed irradiation indication lists generated by multiple artificial intelligence (AI) programs, or chatbots, and compared them to 2020 British Society for Haematology (BSH) practice guidelines. Four chatbots (ChatGPT-3.5, ChatGPT-4, Bard, and Bing Chat) were prompted to list the indications for irradiation to prevent TA-GVHD. Responses were graded for concordance with BSH guidelines. Chatbot response length, discrepancies, and omissions were noted. Chatbot responses differed, but all were relevant, short in length, generally more concordant than discordant with BSH guidelines, and roughly complete. They lacked several indications listed in BSH guidelines and notably differed in their irradiation eligibility criteria for fetuses and neonates. The chatbots variably listed erroneous indications for TA-GVHD prevention, such as patients receiving blood from a donor who is of a different race or ethnicity. This study demonstrates the potential use of generative AI for transfusion medicine and hematology topics but underscores the risk of chatbot medical misinformation. Further study of risk factors for TA-GVHD, as well as the applications of chatbots in transfusion medicine and hematology, is warranted.

Do Children With an Allergic Transfusion Reaction Require Premedication For All Blood Products?

BACKGROUND

Children with a history of allergic transfusion reactions (ATRs) receive antihistamine premedication with or without hydrocortisone to prevent subsequent reactions. We aim to examine the frequency of developing ATRs to subsequent different blood product type transfusions.

METHODS

A retrospective chart review of children who received blood product transfusions (packed red blood cells, platelets, frozen plasma, intravenous immunoglobin, albumin, and cryoprecipitate) and developed ATRs. Cases were identified through Transfusion Transmitted Injuries Surveillance System- Ontario database with a complementary chart review. Demographics and subsequent transfusions records were described.

RESULTS

During this period, 35,925 blood products were transfused to 4153 patients. Thirty-eight ATRs were reported in 30 patients. All ATRs were minor except 1 anaphylaxis to albumin transfusion. Seven patients (23%) developed multiple ATRs, and all of them were of the same blood product type. A total of 60 subsequent different blood product types were transfused to the 7 patients who had multiple ATRs; none of those transfusions caused ATR.

CONCLUSION

In children with a history of ATR, developing a reaction to a different blood product type is rare. Hence, premedicating those transfusions is not warranted.

Challenges for the maintaining the microbiological safety of the UK blood supply

The supply of blood, blood products and components in the UK, as elsewhere, is safe, although there is no cause for complacency. Use of blood, blood products and components is not without risk of morbidity and mortality. Transfusion-transmitted infections (TTIs) continue to occur and may severely affect the health and welfare of recipients. As indicated by recent and current inquiries, public interest in these TTIs is huge. The risk of TTI can be mitigated but not abolished. Measures to reduce risk include screening of donors, testing of donations and, where appropriate, treatment of donations. The introduction of newer screening tests might identify some infectious donations but come at a cost, which could exceed a justifiable limit. Thus, the recognition, detection, reporting and investigation of cases of possible TTIs need to be improved. Recipients of blood should understand that, although transfusion in the UK is safe, it is not free of risk and so should be provided with full information so that properly informed consent can be given.

How do we forecast tomorrow's transfusion? - Next generation transfusion practices to improve recipient safety

Recipient safety measures play a key role in overall transfusion efficacy. The key advances in safety over the first century of transfusion medicine have been the development of techniques to prevent hemolytic transfusion reactions, hemolytic disease of the newborn and transmission of viral pathogens. While these risks remain important, they affect many fewer patients than previously. We propose that some of the most important current safety issues relate to toxicities broadly encompassed by the immunomodulatory effects of allogeneic transfusion. These include (1) universal leukoreduction to mitigate nosocomial infections, inflammation and organ injury, (2) removal of stored supernatant and its attendant toxic contents that cause dysfunctional immunity and organ injury, (3) avoiding infusing ABO incompatible antigen and antibody that can lead to bleeding, platelet refractoriness and inflammation, (3) minimizing prophylactic transfusions (particularly of plasma and platelets) except where benefit is proven, and (4) avoiding use of normal saline which is linked to renal failure and possibly hemolysis. Accompanying these safety measures will be the continued growth of one of the most important safety measures, patient blood management, which has as one benefit the avoidance of unnecessary and harmful transfusions. Reducing the toxicity of transfusions will enhance the improved clinical outcomes seen with patient blood management.

Management of hemolytic transfusion reactions

Delayed hemolytic transfusion reactions (DHTRs) in patients with sickle cell disease are underappreciated and potentially fatal. Patients with DHTRs typically have symptoms of pain or dark urine days to weeks following a red blood cell (RBC) transfusion. In instances of DHTRs with hyperhemolysis, the patient's hemoglobin (Hgb) may be significantly lower than it was pretransfusion, and the Hgb A may drop by more than 50%. In most cases, at least 1 RBC alloantibody and sometimes multiple RBC alloantibodies can be identified during the DHTR, with those antibodies presumably having fallen below the level of detection at the time of the implicated transfusion. However, in up to one-third of cases, no new RBC alloantibodies can be identified posttransfusion. Complement is increasingly being appreciated to play a role in DHTRs and hyperhemolysis, not only due to classic pathway activation (with complement fixed antibody bound to RBCs) but also due to alternative pathway activation (resulting in part from plasma free heme). As such, anti-C5 inhibition has recently been reported to be effective at mitigating hemolysis in the setting of some severe DHTRs. Transfusion avoidance during DHTRs is recommended if possible, with long-term transfusion support advice being less clear; for example, a history of a severe DHTR may lead to questions regarding the safety of transfusions prior to curative therapies such as stem cell transplantation or gene therapy. A better understanding of antibody-positive and antibody-negative DHTRs, including patient- or disease-specific risk factors, is necessary to improve transfusion safety.

How to avoid the problem of erythrocyte alloimmunization in sickle cell disease

Erythrocyte alloimmunization is a major barrier to transfusion in sickle cell disease (SCD) because it can lead to transfusion deadlock and the development of life-threatening hemolytic transfusion reactions (HTRs). Several risk factors have been identified, such as blood group polymorphism in these patients of African ancestry frequently exposed to antigens they do not carry and an inflammatory clinical state of the disease. The most important preventive measure is prophylactic red blood cell antigen matching, and there is a consensus that matching for Rh (D, C, E, c, e) and K antigens should be performed for all SCD patients. However, some patients are high responders and more at risk of developing antibodies and HTRs. For these patients, the extension of matching to other blood groups, including variant antigens of the RH blood group, the use of genotyping rather than serology to characterize significant blood groups, and the prophylactic administration of immunosuppressive treatments remain a matter of debate due to low levels of certainty concerning their effects and the difficulty of determining which patients, other than those already immunized, are at high risk. These issues were recently addressed by a panel of experts established by the American Society of Hematology. Here, we review and stratify the various interventions for preventing alloimmunization, based on the literature and our experience and taking into account the obstacles to their implementation and any future developments required.

A pilot study of stored low titer group O whole blood + component therapy versus component therapy only for civilian trauma patients

BACKGROUND

This pilot assessed transfusion requirements during resuscitation with whole blood followed by standard component therapy (CT) versus CT alone, during a change in practice at a large urban Level I trauma center.

METHODS

This was a single-center prospective cohort pilot study. Male trauma patients received up to 4 units of cold-stored low anti-A, anti-B group O whole blood (LTOWB) as initial resuscitation followed by CT as needed (LTOWB + CT). A control group consisting of women and men who presented when LTOWB was unavailable, received CT only (CT group). Exclusion criteria included antiplatelet or anticoagulant medication and death within 24 hours. The primary outcome was total transfusion volume at 24 hours. Secondary outcomes were mortality, morbidity, and intensive care unit- and hospital-free days.

RESULTS

Thirty-eight patients received LTOWB, with a median of 2.0 (interquartile range [IQR] 1.0-3.0) units of LTOWB transfused. Thirty-two patients received CT only. At 24 hours after presentation, the LTOWB +CT group had received a median of 2,138 mL (IQR, 1,275-3,325 mL) of all blood products. The median for the CT group was 4,225 mL (IQR, 1,900-5,425 mL; p = 0.06) in unadjusted analysis. When adjusted for Injury Severity Score, sex, and positive Focused Assessment with Sonography for Trauma, LTOWB +CT group patients received 3307 mL of blood products, and CT group patients received 3,260 mL in the first 24 hours (p = 0.95). The adjusted median ratio of plasma to red cells transfused was higher in the LTOWB + CT group (0.85 vs. 0.63 at 24 hours after admission; p = 0.043. Adjusted mortality was 4.4% in the LTOWB + CT group, and 11.7% in the CT group (p = 0.19), with similar complications, intensive care unit-, and hospital-free days in both groups.

CONCLUSION

Beginning resuscitation with LTOWB results in equivalent outcomes compared with resuscitation with CT only.

LEVEL OF EVIDENCE

Therapeutic (Prospective study with 1 negative criterion, limited control of confounding factors), level III.

Can RH+ whole blood be safely used as an alternative to RH- product? An analysis of efforts to improve the sustainability of a hospital's low titer group O whole blood program

BACKGROUND

Low-titer group O whole blood (LTO-WB) has recently gained popularity in trauma centers for the acute resuscitation of hemorrhagic shock. However, limited supplies of Rh- product prevent implementation and strain sustainability at many trauma centers. We set out to identify whether Rh+ LTO-WB could be safely substituted for RH- product, regardless of patient's Rh status.

METHODS

Following Institutional Review Board approval, information on all trauma patients receiving prehospital or emergency department transfusion of uncrossed, emergency release LTO-WB (11/17-10/19) were evaluated. Patients were first divided into those who received Rh- versus Rh+ product, the assessed by Rh of the recipient. Serial hemolysis panels, transfusion reactions, and outcomes were compared.

RESULTS

Six hundred thirty-seven consecutive trauma patients received emergency release LTO-WB. Of these, 448 received Rh+ product, while 189 received Rh- LTO-WB. Patients receiving Rh+ product were more likely to be men (81 vs. 70%) and have lower field blood pressure (median 99 vs. 109) and GCS (median 7 vs. 12); all p < 0.05. There were no differences in blood product volume, hemolysis laboratories, transfusion reactions, complications, or survival. We then separated patients by Rh status (577 were Rh+, 70 were Rh-). Rh- patients were older (median age 54 vs. 39), more likely to be women (57 vs. 26%), and more likely to have sustained blunt trauma than their Rh+ counterparts (92 vs. 70%); all p < 0.05. There were no differences in hemolysis laboratories, transfusion reactions, complications, or survival between Rh+ and Rh- patients, regardless of Rh product received.

CONCLUSION

When Rh- whole blood is unavailable or in short supply, Rh+ LTO-WB appears to be a safe alternative for the resuscitation of hemorrhagic shock in both Rh+ and Rh- patients. Use of Rh+ product may help trauma centers incorporate LTO-WB into their hospital and improve sustainability of such programs.

LEVEL OF EVIDENCE

Therapeutic, Level III.

Do We Store Packed Red Blood Cells under "Quasi-Diabetic" Conditions?

Red blood cell (RBC) transfusion is one of the most common therapeutic procedures in modern medicine. Although frequently lifesaving, it often has deleterious side effects. RBC quality is one of the critical factors for transfusion efficacy and safety. The role of various factors in the cells’ ability to maintain their functionality during storage is widely discussed in professional literature. Thus, the extra- and intracellular factors inducing an accelerated RBC aging need to be identified and therapeutically modified. Despite the extensively studied in vivo effect of chronic hyperglycemia on RBC hemodynamic and metabolic properties, as well as on their lifespan, only limited attention has been directed at the high sugar concentration in RBCs storage media, a possible cause of damage to red blood cells. This mini-review aims to compare the biophysical and biochemical changes observed in the red blood cells during cold storage and in patients with non-insulin-dependent diabetes mellitus (NIDDM). Given the well-described corresponding RBC alterations in NIDDM and during cold storage, we may regard the stored (especially long-stored) RBCs as “quasi-diabetic”. Keeping in mind that these RBC modifications may be crucial for the initial steps of microvascular pathogenesis, suitable preventive care for the transfused patients should be considered. We hope that our hypothesis will stimulate targeted experimental research to establish a relationship between a high sugar concentration in a storage medium and a deterioration in cells’ functional properties during storage.

Does ABO and RhD matching matter for platelet transfusion?

Platelets express ABO antigens and are collected in plasma, which contains ABO antibodies as would be consistent with the donor ABO group. Platelet ABO antigens that are incompatible with recipient ABO antibodies may have accelerated clearance from circulation and result in lower count increments. ABO antibodies that are passively transferred from donor plasma may result in hemolysis of recipient red blood cells. Although platelets do not express Rh antigens, they contain small numbers of intact red blood cells or fragments, which can lead to alloimmunization in the recipient. Alloimmunization to the RhD antigen may occur when platelets obtained from RhD-positive donors are transfused to RhD-negative recipients. All of these compatibility considerations must be balanced against the available supply, which may be limited due to the 5- to 7-day shelf life of platelets. This articles describes considerations for platelet ABO and RhD selection for platelet transfusions, including the impact of major ABO incompatibility on count increments, the risks of hemolysis associated with minor ABO incompatibility, and the risk of RhD alloimmunization when RhD-negative patients receive platelets obtained from RhD-positive donors.

Platelet transfusion refractoriness: how do I diagnose and manage?

Platelet refractoriness continues to be a problem for thrombocytopenic patients because the risk of a major spontaneous or life-threatening bleed significantly increases when platelet counts drop below 10 × 109/L. The majority of patients have nonimmune causes driving the refractoriness, such as bleeding, medications, or diffuse intravascular coagulation; however, this article is dedicated to the diagnosis and support of patients with immune-based platelet refractoriness. Antibodies to class I HLA molecules (A and B alleles) are responsible for most immune-based refractory cases, with antibodies to platelet antigens seen much less frequently. Patients may be supported with either crossmatch-compatible or HLA-matched/compatible platelet units. When trying to select HLA units it can be difficult to find a perfect "4 of 4" match for the patient's class IA and IB alleles. In these cases, it is better to use the antibody specificity prediction method, which identifies compatible units that lack antigens recognized by the patient's anti-HLA antibodies. For an algorithmic approach to the patient with platelet refractoriness, see Visual Abstract.

Blood Product Transfusion in Adults: Indications, Adverse Reactions, and Modifications

Millions of units of blood products are transfused annually to patients in the United States. Red blood cells are transfused to improve oxygen-carrying capacity in patients with or at high risk of developing symptomatic anemia. Restrictive transfusion thresholds with lower hemoglobin levels are typically clinically equivalent to more liberal thresholds. Transfusion of plasma corrects clinically significant coagulopathy in patients with or at high risk of bleeding. Mildly abnormal laboratory coagulation values are not predictive of clinical bleeding and should not be corrected with plasma. Transfused platelets prevent or treat bleeding in patients with thrombocytopenia or platelet dysfunction. Cryoprecipitate is transfused to treat hypofibrinogenemia. Many adverse reactions can occur during or after blood product transfusion. Transfusion-associated circulatory overload (i.e., volume overload) is the most common cause of mortality associated with blood products. Modifications to blood products can prevent or decrease the risks of transfusion-related adverse reactions. It is critical to quickly recognize when a reaction is occurring, stop the transfusion, assess, and support the patient. Reporting a reaction to the blood bank is part of ensuring patient safety and supporting hemovigilance efforts.

Improving blood transfusion safety in resource-poor countries: a case study of using leucocyte reduced blood in Uganda

Background:

The majority of blood transfusion safety strategies recommended by the WHO for resource-poor countries focus mainly on reducing the risk of transfusion-transmitted infections (TTIs). Other technologies such as leucocyte reduction may represent complementary strategies for improving transfusion safety.

Objective:

To evaluate the role of using leucocyte reduced blood in a resource-poor country.

Methods:

Pre-storage leucocyte reduced (LR) red blood cells (RBCs) were specially prepared for the Tissue Oxygenation by Transfusion in severe Anaemia and Lactic acidosis (TOTAL) study, at the Uganda Blood Transfusion Services from February 2013 through May 2015. Quality control tests were performed to evaluate the procedure, and the incremental cost of an LR-RBC unit was estimated.

Results:

A total of 608 RBCs units were leucocyte reduced. Quality control tests were performed on 55 random RBCs units. The median (IQR) residual leucocyte count was 4 (0·5–10) WBC/uL, equivalent to 1·8x106 WBC per unit. The estimated incremental unit cost of leucocyte reduction was $37 USD per LR RBC unit.

Conclusion:

Leucocyte reduction of blood in a resource-poor country is doable although relatively costly. As such, its value in resource-poor countries should be weighed against other transfusion safety propositions.

Utility of grey zone testing strategy in transfusion transmissible infection testing in blood bank is of limited value!

Several blood banks use grey zone (GZ) phenomenon (defined as samples with optical density within 10% below the cut off in enzyme immuno-assay [EIA]/chemiluminescence immunoassay [CLIA]) to further augment blood safety. There is paucity of data regarding usefulness of GZ sample and its application in Transfusion Transmissible Infection (TTI) screening procedures in blood transfusion services. We looked at our GZ sample results and their confirmatory test results to verify if it adds to blood safety in our set-up? We performed a prospective analytical study on blood donors' samples over two years. All the donors' samples were screened for TTI using CLIA. Samples with signal/cut-off ratio between ≥0.90 and <1.00 were classified under GZ. They were re-tested in duplicate and submitted to confirmatory testing: Neutralization Test for HBsAg, Immunoblot for HCV, and Western blot for HIV. Among the 50,064 blood donors donating the blood during study period, 573 (1.14%) donors were reactive for HBsAg, HCV, and HIV. Forty-seven (0.1%) TTI samples were GZ, but none was "confirmed positive." The utility of GZ testing seems to be limited. However, this may be continued for sake of "erring on the side of caution" and since this only results in negligible wastage (0.1%) of blood units.

American Society of Hematology 2020 guidelines for sickle cell disease: transfusion support

BACKGROUND

Red cell transfusions remain a mainstay of therapy for patients with sickle cell disease (SCD), but pose significant clinical challenges. Guidance for specific indications and administration of transfusion, as well as screening, prevention, and management of alloimmunization, delayed hemolytic transfusion reactions (DHTRs), and iron overload may improve outcomes.

OBJECTIVE

Our objective was to develop evidence-based guidelines to support patients, clinicians, and other healthcare professionals in their decisions about transfusion support for SCD and the management of transfusion-related complications.

METHODS

The American Society of Hematology formed a multidisciplinary panel that was balanced to minimize bias from conflicts of interest and that included a patient representative. The panel prioritized clinical questions and outcomes. The Mayo Clinic Evidence-Based Practice Research Program supported the guideline development process. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used to form recommendations, which were subject to public comment.

RESULTS

The panel developed 10 recommendations focused on red cell antigen typing and matching, indications, and mode of administration (simple vs red cell exchange), as well as screening, prevention, and management of alloimmunization, DHTRs, and iron overload.

CONCLUSIONS

The majority of panel recommendations were conditional due to the paucity of direct, high-certainty evidence for outcomes of interest. Research priorities were identified, including prospective studies to understand the role of serologic vs genotypic red cell matching, the mechanism of HTRs resulting from specific alloantigens to inform therapy, the role and timing of regular transfusions during pregnancy for women, and the optimal treatment of transfusional iron overload in SCD.

[Blood safety in the Netherlands: prevention of blood-transmitted infections]

Amongst the various blood-safety measures to prevent blood-transmitted infections in transfusion recipients, the most important are the selection of blood donors and the testing for infections of the donations. A look-back procedure aims to inform hospitals about potentially infected blood products and to trace the relevant recipients. The opposite, reverse look-back, can also occur: following a report that a patient has an infection of which blood transfusion may be the possible source, all possibly implicated donors will be screened for the particular agent. Over the period 2007-2017, 84 look-backs were carried out by the Dutch blood product organisation Sanquin. Transmission via blood products of the human immunodeficiency virus, hepatitis C virus, human T-cell Lymphotropic virus or Treponema pallidum were not found. Look-back identified four recipients with hepatitis-B virus infection. These recipients had received a blood product from donors with an occult chronic hepatitis-B virus infection. In the Netherlands, the risks associated with transmission of infection through blood products are minimal; however, transmission may still occur, despite extensive blood-safety measures.

Safer Blood Supply for Transfusion: Which Algorithm Should Be Used to Determine Occult Hepatitis B Infection in Blood Donors?

BACKGROUND

Transfusion-transmitted hepatitis B virus continues to be a problem despite its significantly reduced prevalence. In this study, in addition to screening for the presence of HBsAg in donors' blood, anti-HBc and anti-HBs markers were investigated using the chemiluminescence immunoassay (CLIA) method, and real-time PCR was used to detect HBV DNA.

METHODS

The study's material involved serum samples of 4,073 blood donors. HBsAg, anti-HBs, anti-HBc tests were undertaken using the CLIA method, and HBV DNA's presence was investigated using the real-time PCR method.

RESULTS

HBsAg and anti-HBc tests were negative in 3,331 (81.78%) and positive in 37 (0.90%). For the remaining 705 (17.30%), HBsAg was negative and anti-HBc was positive. According to the results of the anti-HBs test for these samples, HBsAg negativity and anti-HBc and anti-HBs positivity were found in 619 samples (15.19%), while 86 samples (2.11%) were negative for HBsAg and anti-HBs but positive for anti-HBc (isolated anti-HBc positivity). ID-HBV DNA real-time PCR tests were performed on 86 samples. None of the samples was positive for HBV DNA.

CONCLUSIONS

Recommended tests for screening occult HBV infection include anti-HBc, anti-HBs, and/or HBV DNA. Anti-HBc screening may result in loss of donors and blood products, particularly in countries with moderate endemicity of HBV, such as Turkey.

Premedication for the prevention of nonhemolytic transfusion reactions: a systematic review and meta-analysis

BACKGROUND

The efficacy of premedication for the prevention of nonhemolytic transfusion reactions remains controversial. This systematic review and meta-analysis assessed the effect of premedication on the rate of nonhemolytic transfusion reactions after allogeneic blood transfusion.

STUDY DESIGN AND METHODS

We searched the literature using CENTRAL, MEDLINE, EMBASE, ISI Web of Science, and clinicaltrials.gov databases from inception until October 31, 2018. We included all randomized controlled trials comparing premedication to placebo or no treatment in patients receiving any labile blood product. Outcome measures were reported as relative risks (RRs) with 95% confidence intervals (CIs). Data were combined for similar outcomes where appropriate using a random-effects model. Analyses were done at both the patient and transfusion level.

RESULTS

Three randomized trials using acetaminophen and antihistamine as premedication met the inclusion criteria. A total of 517 patients received 4444 red blood cell or platelet transfusions. Pooled patient-level estimates with premedication for all nonhemolytic, febrile nonhemolytic, and minor allergic reactions were RR, 0.92 (95% CI, 0.63-1.35); RR, 0.54 (95% CI, 0.26-1.1); and RR, 1.37 (95% CI 0.81-2.31), respectively. Transfusion-level analyses also showed no benefit with premedication. Of 517 patients randomized, only 27 (5.2%) had a history of transfusion reactions.

CONCLUSION

Routine premedication with acetaminophen and antihistamines did not prevent nonhemolytic transfusion reactions; however, the estimate of effect was greatest for febrile reactions. The impact of premedication in patients with a prior history of transfusion reactions remains unknown and requires further evaluation in future clinical trials.

Examining the Role of Complement in Predicting, Preventing, and Treating Hemolytic Transfusion Reactions

Red blood cell (RBC) transfusion is a critical component of optimal management for a broad range of conditions. Regardless of the indication, pretransfusion testing is required to appropriately match RBC donors and recipients to provide immunologically compatible blood. Although this approach is effective in the vast majority of situations, occasionally, patients will inadvertently receive an incompatible RBC transfusion, which can result in a hemolytic transfusion reaction (HTR). In addition, patients with life-threatening anemia and a complex alloantibody profile, which precludes rapid procurement of compatible RBCs, may also receive incompatible RBCs, placing them at risk for an HTR. Despite the rarity of these clinical situations, when incompatible blood transfusion results in an HTR, the consequences can be devastating. In this review, we will explore the challenges associated with actively preventing and treating acute HTRs following incompatible RBC transfusion. In doing so, we will focus primarily on the role of complement, not only as a key player in HTRs, but also as a potential target for the prevention and treatment of HTRs.

Impacts of Aging on Anemia Tolerance, Transfusion Thresholds, and Patient Blood Management

Evidence-based patient blood management guidelines commonly recommend restrictive hemoglobin thresholds of 70 to 80 g/L for asymptomatic adults. However, most transfusion trials have enrolled adults across a broad age span, with few exclusive to older adults. Our recent meta-analysis of transfusion trials that focused on older adults paradoxically found lower mortality and fewer cardiac complications when these patients were managed using higher hemoglobin thresholds. We postulate that declining cardiac output with age contributes to deteriorating oxygen delivery capacity which impacts anemia-associated outcomes in older adults and propose a model to explain this age-related difference. We reviewed evidence concerning the pathophysiology of aging to explore the disparity in transfusion trial outcomes related to hemoglobin thresholds in different age groups. The literature was searched for normative cardiac output values at different ages in healthy adults. Using normative peak cardiac output data, we modeled oxygen delivery capacity in young, middle-aged, and older adults at a range of hemoglobin levels. Cardiovascular and pulmonary systems are impacted by age-related pathophysiological changes. Diminishing peak cardiac output associated with aging reduces the maximal oxygen delivery achievable under metabolic stress. Hence, at low hemoglobin levels, older adults are more susceptible to tissue hypoxia than younger adults. Our model predicts that an older adult with a hemoglobin of 100 g/L has a similar peak oxygen delivery capacity to a young adult with a hemoglobin of 70 g/L. Age-related pathophysiological changes provide some explanation as to why older adults have a lower tolerance for anemia than younger adults. This indicates the need for patient blood management hemoglobin thresholds specific to older as distinct from younger adults. The primary application of this model is in the consideration of patients rehabilitating to life outside hospital. It is important to note that pathophysiological changes associated with critical illness and major surgery are more complex than can be described in a simple model based on cardiac output and hemoglobin concentration. However, our review of oxygen transport and delivery in health and disease states allows the model to be considered in the context of treatment decisions for anemic adults in a range of hospital and community settings.

A comparison of two protocols for optimal red blood cell depletion using Sepax-2 device for ABO-major incompatible transplantation in adults

PURPOSE OF THE STUDY

In ABO-incompatible bone marrow transplantation, an efficient depletion of red blood cells (RBC) within the graft is mandatory to avoid adverse events in transplanted patients. Using non therapeutic products, we evaluated the substitution of the standard density gradient-based separation (DGBS) over Ficoll-Paque with the use of an automated procedure intended for buffy coat only (SmartRedux software) introducing modifications within the settings to achieve a drastic reduction of the initial volume of the product. Both methods were conducted on the Sepax-2 device.

SAMPLES AND METHODS

RBC depletion rates and CD34+ cells recoveries from eight procedures with SmartRedux software using "in-house" settings (method A) were compared to those obtained from four procedures using NeatCell software, an automated DGBS over Ficoll-Paque (method B).

RESULTS

Median erythrocyte depletion of 95,4% (92,7%-99,0%) and 99,8% (99,0%-99,9%) were observed using methods A and B, respectively. Median residual RBC volumes in the final product were 19 mL (4,4 mL-31,2 mL) and 0,7 mL (0,4 mL-4,7 mL), respectively (p = 0,014). CD34+ cells recoveries of 90,9% (62,7%-102,1%) and 78,4% (64,1%-86,2%) were achieved for methods A and B. Median platelet depletion was 16,6% (10%-42,7%) and 89,8% (88,5%-92,4%) using methods A and B, respectively (p = 0,004). Processing duration was shorter using method A (168 ± 29 min) than method B (295 ± 21 min) (p = 0,004).

CONCLUSION

Both methods achieved satisfactory erythrocyte depletion and CD34+ recovery. The use of Sepax-2 device in association with SmartRedux software could be extended to efficiently deplete RBC from large-volume BM in a raw instead of DGBS.

[Serological screening in donors in Mexico: advances and technology]

The residual risk of transfusion-related infections has decreased dramatically in countries that have routinely implemented serological screening. Most of the donation in Mexico is from replacement practice, a risk factor for positive serology. In Mexico, the altruistic donation is only 2.7%. The heterogeneity of technical factors, regional factors and internal policies of each center influences the variability of data on the prevalence of positive screening, as well as the prevalence of confirmed cases. The main advantage of nucleic acid technology is the detection of donors in the period of serological window or occult infections, being occult hepatitis reports in Mexican donors from 1 to 3.4%. The limitation of available technology, the scope of the clinic and perspectives, invites us to improve technology and health policies in the interest of transfusion safety.

Challenges in preventing and treating hemolytic complications associated with red blood cell transfusion

Red blood cell (RBC) transfusion support represents a critical component of sickle cell disease (SCD) management. However, as with any therapeutic intervention, RBC transfusion is not without risk. Repeat exposure to allogeneic RBCs can result in the development of RBC alloantibodies that can make it difficult to find compatible RBCs for future transfusions and can directly increase the risk of developing acute or delayed hemolytic transfusion reactions, which can be further complicated by hyperhemolysis. Several prophylactic and treatment strategies have been employed in an effort to reduce or prevent hemolytic transfusion reactions. However, conflicting data exist regarding the efficacy of many of these approaches. We will explore the challenges associated with predicting, preventing and treating different types of hemolytic transfusion reactions in patients with SCD in addition to describing future strategies that may aid in the management of the complex transfusion requirements of SCD patients.

[Analysis of irregular antibody screening and antibody identification results in 31 858 cases of inpatients]

Objective To explore clinical significance of transfusion safety by analyzing the results of screening the irregular antibodies and antibody identification. Methods The micro-column gel test cards were used to screen and identify irregular antibodies of 31 858 inpatients. Results Among the 31 858 cases, 31 517 (98.92%) had positive results in RhD detection, and 341 (1.08%) had negative results in RhD detection. The number of patients who had positive results in screening the irregular antibodies was 92 cases and the positive rate was 0.3%. The highest detected rate of positive results in screening the irregular antibodies was obtained in the patients with hematologic diseases at a rate of 2.21% (11/497), closely followed by the pregnant women at a rate of 0.72% (31/4313). The 92 cases had positive results in antibody identification, including 45 cases of anti-E (48.91%), 11 cases of anti-D (11.96%), 10 cases of anti-c (10.87%), 6 cases of anti-Le^a (6.52%), 5 cases of anti-Ec (5.44%), 5 cases of anti-M (5.44%), and 10 cases of other antibodies. Conclusion Screening the irregular antibodies and antibody identification before blood transfusion can effectively avoid the adverse reactions of blood transfusion and improve the quality of blood transfusion.

Shifting ground and gaps in transfusion support of patients with hematological malignancies

The transfusion support of hematological malignancies considers 2 dimensions: the quantity of what we order (in terms of triggers, doses, targets, and intervals), and the special qualities thereof (with respect to depths of matching and appropriate product modifications). Meanwhile, transfusion-related enhancements in the quantity and quality of life may not be dose dependent but rather tempered by unintended patient harms and system strains from overexposure. Evidence and guidelines concur in endorsing clinically noninferior conservative red blood cell (RBC) transfusion care strategies (eg, triggering at hemoglobin <7-8 g/dL and in single-unit doses for stable, nonbleeding inpatients). However, the unique subpopulation of patients with hematological malignancies who are increasingly managed on an outpatient basis, and striving at least as much for quality of life as quantity of life, is left on the edges of these recommendations, with more questions than answers. If a sufficiently specific future wave of evidence can satisfy the concerns (and contest the assumptions) of the remaining proponents of liberalism, and if conservatism is broadly adopted, savings may be potentially immense. These savings can then be reinvested to address other gaps and inconsistencies in RBC transfusion care, such as the best achievable degrees of prophylactic antigen matching that can minimize alloimmunization-related service delays and reactions.

Reactive Blood Donor Notification; Their Responses And Perceptions: Experience From Southern Pakistan

BACKGROUND

Donor notification of reactive status is important to prevent the spread of disease. Response of reactive donors to seek confirmation and treatment is a direct reflection of their knowledge and attitudes towards transfusion transmittable infections.

METHODS

A cross sectional observational study was conducted from August 2014 to July 2015 at the blood bank of a tertiary care hospital, Karachi, Pakistan. Reactive donors' notification and responses were noted with reasons of failure. A cross-sectional analytical survey with non-probability purposive sampling was done on 350 potential consenting blood donors using a pre-tested questionnaire to assess their knowledge and attitude about disease awareness, transmission routes, financial implications and disease sensitization.

RESULTS

Out of 16660 donations, 5.57% were rejected on positive screening tests. Repeat donors (69.5%) with primary to secondary qualifications constituted the bulk of reactive donors. Donor notification rate were 54.25% whereas 28.68% donors responded to blood bank in person. The survey showed limited awareness about transfusion transmitted infections. Respondents who were ignorant of disease spread through blood transfusion comprised of 48%. 96.6% donors did not know the financial impact of treatment and 69.7% were unable to afford it. Moreover, 94.9% donors were not protected against hepatitis B. Participants with secondary education had significantly less odds of being adequately knowledgeable (OR=0.372, 95% CI: 0.203-0.681, p-value <0.01) but more likely to have a positive attitude.

CONCLUSIONS

There is need for structured pre-donation counselling to sensitize donors about transfusion related diseases in resource limited countries where treatment costs are high and out of reach for most donors..

Transfusion-related adverse events are decreased in pregnant women with sickle cell disease by a change in policy from systematic transfusion to prophylactic oxygen therapy at home: A retrospective survey by the international sickle cell disease observatory

Sickle cell disease (SCD) in pregnancy can be associated with adverse maternal and perinatal outcomes. Furthermore, complications of SCD can be aggravated by pregnancy. Optimal prenatal care aims to decrease the occurrence of maternal and fetal complications. A retrospective, French, two-center study compared two care strategies for pregnant women with SCD over two time periods. In the first study period (2005-2010), the women were systematically offered prophylactic transfusions. In the second study period (2011-2014), a targeted transfusion strategy was applied whenever possible, and home-based prophylactic nocturnal oxygen therapy was offered to all the pregnant women. The two periods did not differ significantly in terms of the incidence of vaso-occlusive events. Maternal mortality, perinatal mortality, and obstetric complication rates were also similar in the two periods, as was the incidence of post-transfusion complications (6.1% in 2005-2010 and 1.3% in 2011-2014, P = .15), although no de novo alloimmunizations or delayed hemolysis transfusion reactions were observed in the second period. The results of this preliminary, retrospective study indicate that targeted transfusion plus home-based prophylactic nocturnal oxygen therapy is safe and may decrease transfusion requirements and transfusion-associated complications.

How shall we transfuse Hippolyta?

The US Department of Defense recently made the decision to open direct ground combat roles to women. Blood product transfusion is an essential component of the US Military guidelines for tactical combat casualty care and damage control resuscitation, but blood transfusion carries with it the specific side effect of alloimmunization-a uniquely significant side effect for young women who may desire subsequent pregnancies. Presently to be considered are the changes that may need to be made to blood transfusion in the setting of battlefield medicine to optimally care for combat-injured women, as a majority of the existing data regarding the risks of transfusion in the trauma setting involve predominantly men. This article delves into the possibility of a new cohort of women at risk for hemolytic disease of the fetus and newborn, the need for women's health professionals to appropriately counsel women considering serving in direct ground combat roles about this specific risk, and the appropriate steps that should be considered to provide these women optimal medical care.

Platelet production from induced pluripotent stem cells

Ex vivo production of human platelets has been pursued as an alternative measure to resolve limitations in the supply and safety of current platelet transfusion products. To this end, induced pluripotent stem cells (iPSCs) are considered an ideal global source, as they are not only pluripotent and self-renewing, but are also available from basically any person, have relatively few ethical issues, and are easy to manipulate. From human iPSCs, megakaryocyte (MK) lines with robust proliferation capacity have been established by the introduction of specified sets of genes. These expandable MKs are also cryopreservable and thus would be suitable as master cells for good manufacturing practice (GMP)-grade production of platelets, assuring availability on demand and safety against blood-borne infections. Meanwhile, developments in bioreactors that physically mimic the in vivo environment and discovery of substances that promote thrombopoiesis have yielded competent platelets with improved efficiency. The derivation of platelets from iPSCs could further resolve transfusion-related alloimmune complications through the manufacturing of autologous products and human leukocyte antigen (HLA)-compatible platelets from stocked homologous HLA-type iPSC libraries or by manipulation of HLAs and human platelet antigens (HPAs). Considering these key advances in the field, HLA-deleted platelets could become a universal product that is manufactured at industrial level to safely fulfill almost all demands. In this review, we provide an overview of the ex vivo production of iPSC-derived platelets toward clinical applications, a production that would revolutionize the blood transfusion system and lead the field of iPSC-based regenerative medicine.

Survey on Transfusion-Transmitted Cytomegalovirus and Cytomegalovirus Disease Mitigation

CONTEXT

- Cytomegalovirus (CMV) can be transmitted by cellular blood products, leading to severe disease in immunosuppressed patients such as neonates and transplant recipients. To mitigate transfusion-transmitted CMV (TT-CMV), "CMV-safe" blood products (leukoreduced and/or CMV-seronegative) are transfused. Attempts to develop practice guidelines for TT-CMV mitigation have been limited by paucity of high-quality clinical trials.

OBJECTIVE

- To assess current TT-CMV mitigation strategies across medical institutions for specific at-risk populations.

DESIGN

- Supplemental questions regarding TT-CMV and CMV disease mitigation were added to a College of American Pathologists Transfusion Medicine (Comprehensive) Participant Survey in 2015, addressing whether a given institution provided CMV-safe products for 6 at-risk patient populations.

RESULTS

- Ninety percent (2712 of 3032) of institutions reported providing universally leukoreduced blood products. Among institutions without universal leukoreduction, 92% (295 of 320) provided leukoreduced products on the basis of clinical criteria. Eighty-three percent (2481 of 3004) of respondents reported having availability of CMV-seronegative products; however, wide variation in policies was reported governing CMV-seronegative product use. Among all respondents, less than 5% reported using CMV prophylaxis and monitoring in high-risk patient groups. Transplant centers reported higher rates of CMV prophylaxis (25% [97 of 394] solid organ) and monitoring (15% [59 of 394] solid organ) for CMV-negative transplant recipients.

CONCLUSIONS

- Universal leukoreduction is the primary strategy for mitigating TT-CMV. While most institutions have both CMV-seronegative and leukoreduced blood products available, consensus is lacking on which patients should receive these products. High-quality studies are needed to determine if CMV-seronegative and leukoreduced blood products are needed in high-risk patient populations.

Blood derived products in pediatrics: New laboratory tools for optimizing potency assignment and reducing side effects

Neonates and children can develop rare bleeding disorders due to congenital/acquired coagulation Factor deficiencies, or allo-immune/autoimmune complications, or can undergo surgeries at high haemorrhagic risk. They then need specialized transfusion of blood components/products, or purified blood extracted products or recombinant proteins. Blood-derived therapies conventionally used for management of affected infants with genetic/acquired deficiencies, bleeding problems (coagulation Factor reduced or missing) or thrombotic disorders (reduced or missing anticoagulant proteins) pose some additional risks. These remedial therapies can cause tolerance when used very early in life and, sometimes needed, repeatedly. The introduction of recombinant proteins has allowed manufacturers to produce large amounts of the proteins usually present at very low concentration in blood. This has also changed the risk pattern of plasma-extracted products, especially in terms of continual reduction of viral transmission. Many efforts have been made over these past decades to reduce the risks associated with the use of all these products in terms of viral and bacterial safety, as well as immune disorders but they are not the objective of this article. Other associated side effects are the presence of undesired activities in blood products, which can produce thrombotic events or adverse reactions. The progressive introduction of blood derived products has greatly improved the prognosis and quality of life of affected patients. This concerns whole blood, but also blood cell concentrates, mainly platelets and red blood cells, plasma, while the blood extracted products are increasingly replaced by recombinant proteins. All these therapeutic products, i.e. blood extracted drugs, improve health and quality of life for hemophiliac's A or B, or patients with auto/allo-immune thrombocytopenias or with rare bleeding disorders, and those with thrombotic events occurring in childhood, which are mainly due to Protein C or Protein S deficiencies (congenital or acquired). Progress in analytical methods and biotechnology allow better control of the manufacturing processes for all blood derived or plasma extracted products and recombinant proteins, and contribute to improved manufacturing processes to minimize the occurrence of side effects. These adverse events can be due to the aging of the blood cell concentrate with release of their granule content, and generation of EVs, which can produce anaphylactic reactions and risk of thrombosis, but also to the presence of activated coagulation Factors in purified products, such as Factor Xia as recently identified in immunoglobulin concentrates. Characterization and measurement of contaminant products is of special usefulness during product preparation and for optimization of manufacturing processes for purified extracted products, but also for recombinant proteins. The pharmaceutical industry introduces these new methods for validating manufacturing processes, or for quality control assessments. The objective is first to warrant the full quality and safety of the lots produced, and assure the highest efficacy with the lowest risks when used in patients. For cell concentrates and fresh blood, storage conditions are critical and measurement of analytes such as EVs or Annexin V allows evaluation of quality of each individual transfused pouch. In addition to all the rules around viral and bacterial transmission risk, and immune tolerance, our available laboratory methods contribute to reducing the side effects of blood cell concentrates and derived plasma products, as well as those of the therapeutic recombinant proteins.

A European survey on donor deferral for allergy: Rationale and initial results of a survey in 35 countries

Allergy accounts to near 0.5% of all reported transfusion adverse events. The responsibility of blood components themselves and - therefore - of blood donors is still questioned. The European Community undertook a large international survey to address the consistency and homogeneity of medical selection of blood donors with regard to the risk of allergy, and especially of transferring allergy to recipients. This short report presents the salient points of the survey, stressing that there is inconsistency in addressing the allergy question within countries or systems, with paths of improvement.

[Blood transfusion : optimizing the use of a scarce and expensive resource]

Haemoglobin transfusion threshold remains debated with a high variability of practice among physicians. Several well-conducted studies revealed that a liberal transfusion policy is not only unnecessary, but can also prove harmful in certain situations. Blood transfusion is a costly act involving risks of infection, allergic and hemodynamic. Optimizing the use of this scarce and expensive resource becomes necessary. This article summarizes the different transfusion thresholds to respect in hospital clinical practice, based on the latest international recommendations, while emphasizing the importance of clinical judgment in each situation.

Transfusion reactions: prevention, diagnosis, and treatment

Blood transfusion is one of the most common procedures in patients in hospital so it is imperative that clinicians are knowledgeable about appropriate blood product administration, as well as the signs, symptoms, and management of transfusion reactions. In this Review, we, an international panel, provide a synopsis of the pathophysiology, treatment, and management of each diagnostic category of transfusion reaction using evidence-based recommendations whenever available.

The Prevalence of Red Blood Cell Alloantibodies in Lower Northern Thailand

BACKGROUND

Hemolytic transfusion reactions due to the presence of pre-existing alloantibodies are among the most common immunologic adverse effects in transfusion medicine. In addition to determining the presence and characteristics of the specific alloantibodies, one of the major obstacles is the selection of compatible blood units that lack the corresponding antigens to avoid such transfusion reactions. A delay in this process can lead to various detrimental complications.

OBJECTIVE

To characterize the prevalence and specificity of alloantibodies in patients from lower northern Thailand who required a blood transfusion.

MATERIAL AND METHOD

A retrospective review of the Blood Bank database of Naresuan University, Thailand, was conducted. Thirty one thousand four hundred patients who had been screened for the presence of alloantibodies between January 2007 and April 2014 were reviewed. The standard test tube method was used in all patients to identify the specificity of alloantibodies against red blood cell surface antigens.

RESULTS

Among the 31,400 patients, 169 patients (0.54%) were found to have pre-existing red blood cell alloantibodies. Anti-Mi (anti-Miltenberger blood group) was the most common alloantibody identified (43.79%). Other common alloantibodies were anti-E (18.34%), anti-P1 (17.75%), anti-Lea (17.16%), and anti-Leb (9.47%).

CONCLUSION

To minimize hemolytic transfusion reactions, we recommend greater availability and issuing of Mi, E, P1, Lea, and Leb-matched blood units for patients with known alloantibodies against these antigens, or for patients who require multiple transfusions. This is in addition to the standard pre-transfusion screening and cross-matching processes.

[Contribution of red blood group genotyping for recipients in immune-hematology through three years of activity at the EFS Alpes-Méditerranée]

AIM OF THE STUDY

Current knowledge of the molecular basis of most blood groups enables genetic testing for blood groups to overcome the limitations of agglutination. A retrospective review was carried out on genotyping assays performed between 2011 and 2013.

METHODS AND PATIENTS

The Molecular Hematology Laboratory of the EFS Alpes-Méditerranée implements commercially available tools (BioArray, Gen-Probe) and other techniques (TaqMan, tetra-primer ARMS-PCR, sequencing). It provides a high-level of expertise in molecular biology, complying with regulatory requirements and standards.

RESULTS

A total of 2382 genotyping assays was performed including 764 extended typings and 115 large extended typings essentially in cases involving multiple transfusion and suspected rare blood type. Phenotype discrepancies linked to the RH system accounted for 1501 genotypings. Discrepancies linked to the D and E were mainly related to an allele coding for weak antigen (weak D type 1, 2, 3 and EIV) while those linked to C, c and e antigens were related to an allele coding for a partial antigen (RN, ces(340), ceMo). A high prevalence of (C)ces haplotype in trans of a DAR allele was observed in Afro-Caribbean (54/62).

CONCLUSION

In transfusion medicine, red-cell genotyping can overcome the limitations of hemagglutination. It must be used only in situations where it provides a benefit either for the patient or resource management. For implementation of appropriate transfusional practices, this technique requires a sound knowledge of the genetic characteristics of blood groups and clinically relevant variants. It also requires competency with molecular biology tools and continuously updated scientific data.