Is it reasonable for the use of Rh-ee blood? A hospital-based survey from a southern medical center in Taiwan.

Identification of alloantibodies and achieving a reduction in the rate of red blood cell (RBC) alloimmunization are important issues to prevent transfusion complications. The aim of this study was to identify the antigen and alloantibodies in our patients and to study the association of alloimmunization with previous transfusion. Transfusion records from the blood bank of Kaohsiung Medical University Hospital between 2015 and 2017 were retrospectively enrolled in the study. Antigen and antibody identification was performed using routine blood bank methods. In total, 56,422 transfusion records from 2015 to 2017 were included in the study. Among them, 1858 alloantibody episodes were found in the pre-transfusion survey, and anti-Mia, anti-E, and cold antibodies were the most common alloantibodies, with a prevalence of 3.29% (1858/56,422). Among them, 130 episodes involved newly found alloantibodies with no alloantibodies found in the previous transfusion survey. Tracing back to these newly transfusion-induced alloantibodies, the antibody was found with a mean of 10.8 ± 7.8 units of packed RBC transfusion, a mean of 66.3 ± 52.8 days, and with a mean of 4.3 ± 2.7 times of transfusion from the first transfusion therapy. An antibody survey revealed that Rh-ee (62.1%) was the most common phenotype in these newly identified antibodies. In summary, this hospital-based study revealed that RBC alloantibody rates were present at rates of 3.29%, with anti-Mia, anti-E, and cold antibodies being the most common alloantibodies. Among them, anti-E was the most commonly developed alloantibody. Given that the Rh-ee group is the most common phenotype in our population, the strategy of using Rh-ee blood for Rh-ee recipients is reasonable for transfusion safety.

Non-transfusion dependent thalassemia is independently associated with higher alloimmunization risk than transfusion dependent thalassemia and would benefit the most from extended red cell antigen-matching.

BACKGROUND: Alloimmunization prevalence is conventionally used to identify RBCs alloimmunization risk factors among thalassemia patients, but it may be confounded by differences in transfusion exposure especially between non-transfusion dependent thalassemia (NTDT) and transfusion dependent thalassemia (TDT) patients. To better identify thalassemia patients with high alloimmunization risks, we used cumulative incidence of first alloimmunization as a function of RBCs transfused to compare alloimmunization risks between TDT and NTDT and to evaluate other risk factors. We also proposed practical strategies to prevent alloimmunization in thalassemia. STUDY DESIGN AND METHODS: Adult TDT and NTDT patients who had received ≥2 transfusions and no alloimmunization before their first transfusion were included. Alloimmunization was defined as the development of clinically significant alloantibodies. We estimated the first alloimmunization incidence from transfusion by Kaplan-Meier analysis with the horizontal axis expressed as cumulative non-antigen-matched RBC units transfused. We compared this incidence between TDT and NTDT, and analyzed for other alloimmunization risk factors and the alloantibody specificities/frequencies. RESULTS: The alloimmunization prevalence was similar between TDT and NTDT (27% vs. 30% respectively, p = .726). However, for the same transfusion exposure, NTDT had higher alloimmunization incidence than TDT (hazard ratio 8.59, 95% confidence interval [2.25-32.74], p = .002), independent of age at first transfusion and last follow-up, gender, and splenectomy. Anti-E, anti-c, anti-Mia , and anti-Jka were most frequent. DISCUSSION: NTDT has the highest alloimmunization risk and would benefit the most from extended RBC antigen-matching, especially C, c, E, and e. Other blood group antigen-matching should be guided by the patient/donor disparities and alloantibody frequencies in different populations.

COVID-19 clinical course and blood groups: Turkish population-based study

Background/aim: SARS-CoV-2 enters the cell through the binding of the S glycoprotein on the surface of the virus to the angiotensin- converting enzyme 2 (ACE-2) in the host cells and also SARS-CoV S protein binding to ACE-2 was inhibited by anti-A antibodies. The aim of the study was to investigate the relationship between blood groups and the course of COVID-19 in Turkey. Materials and methods: Laboratory confirmed COVID-19 patients aged 18 and over (n = 39.850) were randomized in age and sex- matched groups according to blood groups. Results: Advanced age, male sex and blood group A were found to be related with increased rate of intensive care unit (ICU) admission (OR = 1.089, 95% CI: 1.085­1.093 for age; OR = 1.963, 95% CI: 1.737­2.218 for male sex; OR = 1.216, 95% CI: 1.023­1.446 for blood group A). When blood group O individuals were compared to non-O individuals, no significant difference was observed regarding the rate of hospital and ICU admission, mechanical ventilation (MV) support, length of hospital and ICU stay, and case fatality rate (CFR). The CFR in patients with blood group A, B, O, and AB were 2.6%, 2.2%, 3.1%, and 2.3%, respectively. There were no significant differences between Rh-negative and positive patients regarding the rate of hospital and ICU admission (p = 0.280 and p = 0.741, respectively), also the rate of MV support and CFR was similar (p = 0.933 and p = 0.417). Conclusion: Our study revealed that ABO and Rh blood groups do not have any impact on the rate of hospital admission, hospital and ICU stay, MV support, and CFR.

Adapting to supply-and-demand emerging trends for antigen-negative red blood cell units.

BACKGROUND: A global downtrend in blood usage has been observed by many countries, while the demand for antigen-negative red blood cell (RBC) units used in antigen-matched transfusions keeps increasing. The declining number of units collected exposes blood providers to a rapidly evolving supply challenge. METHODS: This study was conducted retrospectively with use of internal data analysis to weigh Québec's situation regarding global and antigen-negative RBC demand, to measure the effects of community-directed recruitment and blood drives, and to evaluate the benefits of mass-scale RBC genotyping. RESULTS: Our findings confirm a global RBC usage downtrend of over 20% total in the past 10 years with a steady antigen-negative usage and highlight the most requested negative antigen combinations. Our data also show our +39.5% progress regarding the number of Black donors recruited for antigen matching of patients with sickle cell disease in the past 3 years, as well as a constantly growing number of just-in-time blood collection for complex orders. Finally, our data summarize the efficiency of our mass-scale RBC genotyping efforts. CONCLUSION: Altogether, this study confirms the demand trends for regular and antigen-negative RBC units in Québec and the efficient effects of our recruitment and typing strategies.

Role of prothrombin 19911 A>G polymorphism, blood group and male gender in patients with venous thromboembolism: Results of a German cohort study.

The role of the A>G polymorphism at position 19911 in the prothrombin gene (factor [F] 2 at rs3136516) as a risk factor for venous thromboembolism [VTE] is still unclear. To evaluate the presence of the F2 polymorphism in VTE patients compared to healthy blood donors and to adjust the results for common inherited thrombophilias [IT], age at onset and blood group [BG], and to calculate the risk of VTE recurrence. We investigated 1012 Caucasian patients with a diagnosis of VTE for the presence of the F2 rs3136516 polymorphism and compared these with 902 healthy blood donors. Odds ratios [OR] together with their 95% confidence intervals were calculated adjusted for F5 at rs6025, F2 at rs1799963, blood group, age and gender. In addition, we evaluated the risk of recurrent VTE during patient follow-up calculating hazard ratios [HR] together with their 95% CI. Compared with the AA wildtype, the F2 GG and AG genotypes (rs3136516) were associated with VTE (OR 1.48 and 1.45). The OR in F5 carriers compared to controls was 5.68 and 2.38 in patients with F2 (rs1799963). BG "non-O" was significantly more often diagnosed in patients compared to BG "O" (OR 2.74). VTE recurrence more often occurred in males (HR 2.3) and in carriers with combined thrombophilia (HR 2.11). Noteworthy, the rs3136516 polymorphism alone was not associated significantly with recurrence. In Caucasian patients with VTE the F2 GG/GA genotypes (rs3136516) were moderate risk factors for VTE. Recurrence was associated with male gender and combined thrombophilia.

Dal-induced red blood cell incompatibilities in a Doberman Pinscher with von Willebrand factor deficiency and ehrlichiosis.

OBJECTIVE: To describe a complex case involving the management of a dog with von Willebrand disease (vWD), active ehrlichiosis infection, nonregenerative anemia, and blood type incompatibility related to the Dal antigen. CASE SUMMARY: A 13-week-oldintact male Doberman Pinscher weighing 7.2 kg was presented to the emergency service for a previous hemorrhaging event and progressive nonregenerative anemia. The dog had received a fresh whole blood transfusion 8 days prior to presentation due to severe anemia. Upon presentation, the puppy was tachycardic, and his mucous membranes were pale. A CBC revealed a nonregenerative anemia with a PCV of 0.11 L/L (11%). von Willebrand factor deficiency was suspected and later confirmed. The dog's blood type was dog erythrocyte antigen (DEA) 1 positive, but cross-matching to 4 RBC units, both DEA 1 positive and negative, failed to yield any compatible units. Antibody against a possible Dal RBC antigen was suspected, and 11 blood donors (Dalmatians and Dobermans) were cross-matched to find 2 compatible donors. After an uneventful fresh whole blood transfusion, a bone marrow biopsy revealed a hypocellular bone marrow and erythroid hypoplasia. A SNAP4DxPlus test and subsequent polymerase chain reaction (PCR) testing were positive for Ehrlichia ewingii and E. canis. Treatment with doxycycline was started, and the PCV was 0.17 L/L (17%) at discharge. At the 1-week follow-up, the PCV was 0.24 L/L (24%), and the puppy was doing well. NEW OR UNIQUE INFORMATION PROVIDED: This is a unique case of a dog presenting with several challenging disorders, including vWD resulting in hemorrhage, ehrlichiosis potentially contributing to a nonregenerative anemia, and a blood type incompatibility due to the Dal antigen. Doberman Pinschers have a high prevalence of vWD- and Dal-negative phenotype, which emphasizes the value of cross-matching and the recognition of antigen prevalence in specific breeds.

Blood management in a patient with anti-Oka antibody who underwent cardiac surgery using cardiopulmonary bypass: a case report.

BACKGROUND: Cardiac surgery under cardiopulmonary bypass (CPB) is often associated with massive bleeding and blood transfusion. For patients requiring specific blood products, meticulous blood management is critical to reduce blood loss, as well as the need for transfusion. Here, we have described the intraoperative blood management in a patient with anti-Oka antibody, who underwent cardiac surgery with CPB. CASE PRESENTATION: A 79-year-old woman was scheduled for open aortic valve replacement and tricuspid valve annuloplasty under hypothermic CPB. Her blood type was A RhD(+) Ok(a-), and anti-Oka, an extremely rare antibody against erythrocyte antigen, was detected. Eight units of Ok(a-) frozen thawed red cells (FTRCs), and six units of red blood cells donated by three Ok(a-) individuals were collected just prior to surgery. Although she was anemic, acute normovolemic hemodilution was conducted after anesthesia induction to preserve the autologous whole blood. Four units of FTRCs were loaded in the CPB priming solution, and modified ultrafiltration was adopted during CPB to prevent further hemodilution. After CPB termination, two units of FTRCs, four units of fresh frozen plasma, and ten units of platelet concentrate were intensively transfused, facilitating surgical hemostasis and stable hemodynamics. The autologous whole blood was returned to the patient in the intensive care unit. Since the hemoglobin and hematocrit levels were maintained postoperatively, no additional transfusion was required throughout her hospital stay. CONCLUSIONS: Multidisciplinary intraoperative blood management in a patient with anti-Oka antibody facilitated successful cardiac surgery using CPB, along with effective use of limited blood products.

Blood type and outcomes in patients with COVID-19.

This study aimed to determine if there is an association between ABO blood type and severity of COVID-19 defined by intubation or death as well as ascertain if there is variability in testing positive for COVID-19 between blood types. In a multi-institutional study, all adult patients who tested positive for COVID-19 across five hospitals were identified and included from March 6th to April 16th, 2020. Hospitalization, intubation, and death were evaluated for association with blood type. Univariate analysis was conducted using standard techniques and logistic regression was used to determine the independent effect of blood type on intubation and/or death and positive testing. During the study period, there were 7648 patients who received COVID-19 testing throughout the institutions. Of these, 1289 tested positive with a known blood type. A total of 484 (37.5%) were admitted to hospital, 123 (9.5%) were admitted to the ICU, 108 (8.4%) were intubated, 3 (0.2%) required ECMO, and 89 (6.9%) died. Of the 1289 patients who tested positive, 440 (34.2%) were blood type A, 201 (15.6%) were blood type B, 61 (4.7%) were blood type AB, and 587 (45.5%) were blood type O. On univariate analysis, there was no association between blood type and any of the peak inflammatory markers (peak WBC, p = 0.25; peak LDH, p = 0.40; peak ESR, p = 0.16; peak CRP, p = 0.14) nor between blood type and any of the clinical outcomes of severity (admission p = 0.20, ICU admission p = 0.94, intubation p = 0.93, proning while intubated p = 0.58, ECMO p = 0.09, and death p = 0.49). After multivariable analysis, blood type was not independently associated with risk of intubation or death (referent blood type A; blood type B: AOR: 0.72, 95% CI: 0.42-1.26, blood type AB: AOR: 0.78, CI: 0.33-1.87, blood type O: AOR: 0.77, CI: 0.51-1.16), rhesus factor positive (Rh+): AOR: 1.03, CI: 0.93-1.86. Blood type A had no correlation with positive testing (AOR: 1.00, CI: 0.88-1.13), blood type B was associated with higher odds of testing positive for disease (AOR: 1.28, CI: 1.08-1.52), AB was also associated with higher odds of testing positive (AOR: 1.37, CI: 1.02-1.83), and O was associated with a lower risk of testing positive (AOR: 0.84, CI: 0.75-0.95). Rh+ status was associated with higher odds of testing positive (AOR: 1.23, CI: 1.003-1.50). Blood type was not associated with risk of intubation or death in patients with COVID-19. Patients with blood types B and AB who received a test were more likely to test positive and blood type O was less likely to test positive. Rh+ patients were more likely to test positive.

Relationship between ABO blood groups and preeclampsia.

OBJECTIVE: To investigate the relationship between ABO blood group and preeclampsia.Methods: A case-control study was conducted, including 230 and 460 women with and without preeclampsia. ABO blood groups were compared and associated factors for preeclampsia were determined.Results: Blood group O was significantly more common in early-onset and less common in late-onset preeclampsia. Regression analysis showed that blood group O decreased the risk of late-onset preeclampsia (aOR 0.63, 95%CI 0.42-0.93) but increased the risk of early-onset preeclampsia (aOR 1.97 95%CI 1.05-3.69).Conclusion: Blood group O decreased the risk of late-onset preeclampsia while it increased the risk of early-onset preeclampsia.

Rare case of Auto immune haemolytic anaemia in an infant with auto "f & kidd antibodies".

BACKGROUND: "f" antigen is a compound antigen in Rh blood group system. Anti f has haemolytic potential as described in literature. Its occurrence in an infant as autoantibody with another blood group system ie Jka is very rare. Case report We report a case of 10-month-old infant diagnosed with AIHA with autoantibodies directed towards "f" and Jka antigen. Antibody identification was done and antigen negative blood units were crossmatched & transfused with demonstrable haemoglobin rise and subsequent decrease in DAT grading. RESULT: Auto anti f + Jka was identified in a 10 months old infant. Autoantibodies were identified by identification 3 & 11 cell panel and select cell panel. Results were later confirmed by allogenic adsorption & elution. Patient was transfused antigen negative blood unit which lead to haemoglobin rise & gradual decrease in direct coombs test grading CONCLUSION: To our knowledge, this is the first case report of auto anti f + Jka having haemolytic potential in an infant which shows the importance of extensive immmunohaematology workup in providing compatible blood unit in patients with autoantibody.

Association of ABO blood groups with allergic diseases: a scoping review.

OBJECTIVE: The objective of this study was to map evidence of the association of ABO blood groups with allergic diseases such as allergic rhinitis (AR), atopic dermatitis (AD) and asthma. DESIGN: A scoping review. DATA SOURCES: PubMed, Scopus, Direct Open Access Journal, Medline, Cumulative Index to Nursing and Allied Health Literature, ScienceDirect and SpringerLink were searched from October 2017 until May 2018. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: We selected all types of studies including case-control studies, prospective or retrospective cohort studies, cross-sectional studies and experimental studies, and we included reviews such as literature reviews, systematic reviews with or without meta-analysis and scoping reviews that were published in English and associated the ABO blood group with the three allergic diseases (asthma, AR and AD) in humans of all age groups. DATA EXTRACTION AND SYNTHESIS: Two reviewers independently screened the titles and abstracts and assessed the full-text articles of the abstracts that met the eligibility requirements. Data from the included studies were extracted, evaluated and reported in the form of narrative synthesis. RESULTS: Of the 10 246 retrieved titles, only 14 articles were selected for a scoping review based on the eligibility criteria. The majority of the studies demonstrated a significant association between ABO blood groups and allergic diseases. We found that blood group O is prominent in patients with AR and asthma, while a non-O blood group is common in patients with AD. CONCLUSION: This scoping review serves as preliminary evidence for the association of ABO blood groups with allergic diseases. Further studies need to be conducted so that the relationship between ABO blood groups and allergic diseases can be fully established. This could be helpful for clinicians and health professionals in consulting and managing patients who suffer from allergic diseases in the future.

Updates on practical ABC blood compatibility testing in cats. / Neuigkeiten zur praktischen ABC-Blutgruppen-Bestimmung bei Katzen.

In feline practice, blood groups were considered unimportant until the 1980s. Since then much has been learned. The most important blood group system in cats is the AB (renamed here as ABC) blood group system consisting of blood types A, B and AB (better referred to as C). Type B cats have strong anti-A alloantibodies potentially leading to incompatibility reactions during A-B mismatched transfusions or neonatal isoerythrolysis (NI) in type A and C (AB) kittens born to type B queens. Acute hemolytic transfusion reactions as well as NI have been clinically well documented in cats. Immunological and genetic tests have been established and blood typing and crossmatching test kits have become commercially available. This review updates the current knowledge of these blood types, their genetics, associated incompatibility reactions, and different diagnostic tools for avoiding such reactions in clinical practice.

Blood group antigen and phenotype prevalence in the Korean population compared to other ethnic populations and its association with RBC alloantibody frequency.

OBJECTIVES: This study aimed to analyse the allele frequency of blood group antigens in the Korean population and other ethnic populations and the association of blood group antigens with red blood cell (RBC) alloantibodies. BACKGROUND: Blood group antigen genotyping can support patients undergoing frequent transfusions who have alloantibodies and antibodies against high-prevalence blood group antigens. METHODS: Twenty-nine single nucleotide variations and 37 blood group antigens were tested. Samples requested for routine blood typing were collected from Jan to Apr 2016. Genotyping was performed on 145 Korean samples and was confirmed by bidirectional sequencing and serologic tests. The allele frequency data were compared with previous genotyping datasets (three datasets from Korea and one each from China, Europe, Asia, and the USA). Alloantibody frequencies and blood group antigens from the electronic medical record of 1772 cases were examined. RESULTS: E antigen was higher in the Korean population compared to that of Asian and European populations. K, Kpa , Fyb and Doa allele frequencies were lower compared to other ethnic populations. RBC alloantibodies with frequencies (%) greater than 1% from the 1772 cases were as follows: anti-E, 36·7%, anti-C, 17·7%; anti-c 7·39%; anti-M, 5·9%; anti-e, 5·2%; anti-Jka , 2·9%; and anti-Fya , 1·1%. Blood group antigens and alloantibody frequencies revealed inverse trends that did not reach statistical significance. CONCLUSION: The allele frequency of blood group antigens assessed by high-throughput methods provided reliable and valuable information that could be used for maintaining donor pools and providing compatible blood for genotyped patients.

A case report on anti-Mia antibody in a multi-transfused patient from India.

GP.Mur antigen belongs to the MNSs system and the corresponding antibody is called as anti-Mia antibody. Anti-Mia antibody is a clinically significant antibody capable of causing haemolytic disease of the new born (HDFN) and intravascular haemolytic transfusion reactions. Literature on anti-Mia antibody from India is very limited. We report here a case of anti-Mia antibody in a multi-transfused patient from India.

Coronary Heart Disease and ABO Blood Group in Diabetic Women: A Case-Control Study.

Numerous investigations conducted in general population have reported that certain ABO blood group may increase the risk of coronary heart disease (CHD). However, this association has not been yet well established and even is less clear in diabetic patients. Considering that women with type 2 diabetes mellitus (T2DM) are at greater risk to develop CHD and have higher cardiovascular mortality, this study aimed to evaluate the association between CHD and ABO blood group in women with T2DM. A case control study of eight hundred eighty-one (881) diabetic women was enrolled in this study. Among them, two hundred thirty eight (238) patients were identified to have CHD (CHD+) and two hundred eighty two (282) of them were identified without CHD but matched with the first group for other CHD risk factors (CHD-). ABO blood type (A, B, AB, O, and Rhesus factor) for both groups were determined. To compare the magnitude of the correlation between various blood groups with CHD development, odd ratios (OR) with 95% confidence intervals (CI) was calculated. Our results demonstrates that the percentage of AB blood group was significantly higher in the diabetic women with concurrent CHD than in those without CHD [30 (12.7%) vs. 13 (4.6%), Odd ratio: 2.9 (95%CI: 1.5-5.7), P = 0.001]. The results of the present study clearly demonstrate that the AB blood group has a higher odd ratio for the development of CHD and can be considered as a risk factor for the development of CHD in females with T2DM. More comprehensive studies are required to confirm these results.

A national Transfusion Register of Irregular Antibodies and Cross (X)-match Problems: TRIX, a 10-year analysis.

BACKGROUND: The Transfusion Register of Irregular Antibodies and Cross-match Problems (TRIX) is a unique national database in the Netherlands that was launched in 2007. Transfusion laboratories register the presence of irregular RBC alloantibodies for their patients and can consult the database for information that is relevant for pretransfusion testing, unknown in their own laboratory information system. STUDY DESIGN AND METHODS: Data from the TRIX database 10 years after implementation have been analyzed to demonstrate the added value of TRIX for transfusion practice. TRIX antibody registration, antibody disappearance likelihood, and differences between men and women have been analyzed and evaluated. RESULTS: In the 10-year period 2007 to 2016, a total of 80,164 alloantibodies have been identified and registered in 62,110 individuals. Of the antibodies, 81% were reported in women and 19% in men (female:male, 4.3:1). Rh (DCcEe and Cw ), K, Fya , and Jka antibodies account for 65.6% of all antibody registrations. M and Lewis antibodies account for 18.6% of all antibodies. Antibody disappearance likelihood is relatively high for the clinically relevant antibodies directed against Jkb , s, Fyb , and e. Antibodies directed against D, Fya , and K have a relatively low antibody disappearance likelihood. CONCLUSION: TRIX is a unique and useful tool for transfusion laboratories for timely and up-to-date information on the presence of erythrocyte antibodies, which improves pretransfusion testing and compatible blood selection. TRIX also provides macro data on the prevalence of individual antibodies and antibody disappearance likelihoods that can be used for developing blood type matching strategies for patient groups at risk. © 2019 AABB.

Transfusion service knowledge and immunohaematological practices related to sickle cell disease and thalassemia.

OBJECTIVES: To assess current knowledge of National Heart, Lung and Blood Institutes (NHLBI) and Thalassemia International Federation (TIF) recommendations, blood banking practices and perceived challenges among transfusion services in the management of patients with haemoglobinopathies. BACKGROUND: Previous reports have demonstrated variations in transfusion practices for sickle cell disease (SCD) and thalassemia patients. Recently, NHLBI/TIF have provided transfusion recommendations for patients with haemoglobinopathies. METHODS: A cross-sectional survey was conducted of transfusion services from the state of Georgia previously identified as having SCD/thalassemia populations. The survey assessed transfusion service practices in pre-transfusion testing and blood product selection; awareness/implementation of NHLBI/TIF transfusion-based recommendations and perceived challenges in transfusing haemoglobinopathy patients. RESULTS: Responses were received from 35 of 49 (71%) institutions. Only institutions indicating transfusing SCD or thalassemia patients (32) were included in analysis. Seventy-one percent of non-sickle cell treatment centres (SCTCs) and 20% of non-thalassemia treatment centres follow NHLBI and TIF recommendations to perform a red blood cell phenotype beyond ABO/Rh(D) and provide Rh and Kell prophylactically matched units for SCD and thalassemia patients, respectively. Forty percent of institutions (33% of non-SCTCs) employ RBC genotyping to evaluate the red cell phenotype for SCD patients. Over 77% of institutions do not utilise a reliable method to identify SCD patients prior to transfusion, such as a required question/answer field on type/screen or crossmatch orders. CONCLUSION: Many healthcare systems' transfusion practices for haemoglobinopathy patients are discordant with NHLBI/TIF recommendations. Efforts are needed to increase awareness and implementation of current recommendations among all transfusion services seeing these patients.

RBC alloantibody prevalence and specificity in a Western Norwegian tertiary hospital.

BACKGROUND AND OBJECTIVE: Although several studies focus on red blood cell (RBC) alloantibody distribution in selected patient populations, few address the specificity and frequency in all relevant groups. This study reports alloantibody frequency, distribution and the relationship to age and gender in blood donors, pregnant women and potential recipients of blood products. METHODS: This historical cohort study included 55 462 consecutive antibody screening tests from a tertiary Western Norwegian Hospital. Descriptive statistics were performed, and the results were compared with the literature. RESULTS: The detection and immunisation frequency for the whole cohort were 0·39 and 0·51%, respectively, whereas the RBC alloantibody prevalence was 0·73%. The most frequent RBC alloantibodies were anti-E (20·1%), anti-M (18·7%), anti-K (9·8%), anti-D (8·9%) and anti-Fy(a) (7·0%). In pregnant women, the most frequent RBC alloantibodies were anti-M, anti-D and anti-Le(a) (20·8, 18·9 and 18·9%, respectively), whereas there was no anti-K detected. Anti-E and anti-M were the dominating RBC alloantibodies in the pre-transfusion testing of in-hospital patients (24·1 and 17·1%, respectively). Eighteen (9·2%) persons in the total cohort had two RBC alloantibodies, six persons had three alloantibodies, and two persons had four alloantibodies. Rh and K typing to prevent future immunisations was only performed in 21·0% of the individuals who presented with a new alloantibody; despite that, 50·5% of the detected alloantibodies had such specificities. CONCLUSIONS: The immunisation frequency and the level of anti-K are low compared to national and international studies. Rh and K phenotype-matched blood transfusions might be a feasible future strategy to further decrease RBC alloantibodies.

Modeling rare blood in Canada.

BACKGROUND: Many countries maintain rare blood programs to provide access to blood for patients with complex serologies. These include a process to screen donors and a registry to record information about rare donors; blood agencies may also freeze some units. However, frozen blood is much more expensive than liquid blood. STUDY DESIGN AND METHODS: A two-phase approach to analysis was used to evaluate how rare a blood type must be before a frozen inventory is necessary and what screening rates are required to support a rare blood program. A simulation model was employed to evaluate the impact of inventory on patient access. RESULTS: Results suggested that, for 27 of 29 phenotypes managed by Canadian Blood Services, insufficient donors had been identified to ensure a stable inventory. Analytic results showed the screening rate necessary to ensure a stable inventory and the time frame to build a rare donor base. Twenty-nine simulation scenarios were executed to evaluate patient access to rare blood against inventory levels. Results show that some amount of frozen inventory is necessary for phenotypes rarer than 1 in 3000. However, holding more than two units apiece of O-, O+, A-, and A+ did not improve patient access. CONCLUSION: While some level of frozen blood is needed for rare blood, large inventories do not improve access. Modest amounts of frozen inventory, combined with increased door screening, provides the greatest chance of maximizing patient access.