Rare Donor Research Articles

Serologic investigation and management of an antibody screen negative para-Bombay phenotype during pregnancy

Abstract Introduction/Objective Individuals with the Bombay and para-Bombay red blood cell (RBC) phenotypes express anti- H antibodies associated with acute hemolytic transfusion reactions. The rarity of compatible donor units creates unique logistical challenges. However, para-Bombay individuals have been shown to tolerate transfusion of non- Bombay RBCs without acute hemolysis. Therefore, accurate serologic identification and judicious management of blood products are crucial when planning to transfuse patients with anti-H. This is especially true during pregnancy, as early onset of labor and fetal distress can occur without warning. Methods/Case Report A 24-year-old gravida 2 para 1 (G2P1) at approximately 38 weeks gestation with the fetus in breech position was transferred to our hospital after anti-H antibodies were detected. Although our in-house antibody screen was negative on automated solid-phase red cell adherence (SPRCA) testing, manual tube testing revealed the presence of anti-H antibodies, and forward typing with Ulex europaeus lectin confirmed the absence of H-antigen. Further, Lewis B phenotyping and saliva neutralization demonstrated the presence of H-antigen in secretions, consistent with the O-para-Bombay phenotype. Finally, differential adsorption ruled out other clinically significant allo- antibodies. An external cephalic version (ECV) was initially planned since vaginal delivery carries lower bleeding risk than cesarean section (CS). Three frozen Bombay RBC units were obtained, with one possibly compromised before arrival. Four pre-warmed, cross-match compatible units of O-positive RBCs (non-Bombay) were also prepared. Acknowledging the unpredictability of ECV, the challenge of timing thawed frozen units, and the possibilities of massive hemorrhage versus wasting rare donor blood, our transfusion service ultimately recommended an elective CS with only one Bombay unit deglycerolized. The patient underwent an uneventful procedure without transfusion. Results (if a Case Study enter NA) NA Conclusion Overall, this case highlights key diagnostic and management considerations for patients with Bombay and para-Bombay phenotypes. First, automated SPRCA testing may provide false negative results for anti-H antibodies. Second, backup transfusion strategies for para-Bombay patients may include non-Bombay RBCs. Finally, the procurement, preparation, and use of rare donor blood products requires multidisciplinary clinical decision-making to optimize patient outcomes, especially for high-risk labor when unexpected acute bleeding events can occur.

How anti-c in a D- patient prompted lifesaving work between a transfusion service and a blood center reference laboratory.

This case report showcases an extraordinary collaboration to support the transfusion needs of a patient with a rare phenotype and long-standing anemia due to gastrointestinal bleeding. This report describes the Immunohematology Reference Laboratory testing and logistics of rare blood provision over an 11-year period, as well as a summary of the hematologic, gastroenterologic, and surgical interventions. This case illustrates how a strong collaboration among the clinical team, laboratory, blood center, and the rare donor community facilitated successful management of this patient's anemia until the patient could receive life-changing treatment.

Meeting the transfusion needs of a patient with anti-Ena requires an international effort.

This extraordinary case showcases the identification of a rare anti-Ena specificity that was assisted by DNA-based red blood cell antigen typing and collaboration between the hospital blood bank in the United States, the home blood center in Qatar, the blood center Immunohematology Reference Laboratory, as well as the American Rare Donor Program (ARDP) and the International Society for Blood Transfusion (ISBT) International Rare Donor Panel. Ena is a high-prevalence antigen, and blood samples from over 200 individuals of the extended family in Qatar were crossmatched against the patient's plasma with one compatible En(a-) individual identified. The ISBT International Rare Donor Panel identified an additional donor in Canada, resulting in a total of two En(a-) individuals available to donate blood for the patient.

Perspectives on the Novel Multifunctional Nerve Guidance Conduits: From Specific Regenerative Procedures to Motor Function Rebuilding.

Peripheral nerve injury potentially destroys the quality of life by inducing functional movement disorders and sensory capacity loss, which results in severe disability and substantial psychological, social, and financial burdens. Autologous nerve grafting has been commonly used as treatment in the clinic; however, its rare donor availability limits its application. A series of artificial nerve guidance conduits (NGCs) with advanced architectures are also proposed to promote injured peripheral nerve regeneration, which is a complicated process from axon sprouting to targeted muscle reinnervation. Therefore, exploring the interactions between sophisticated NGC complexes and versatile cells during each process including axon sprouting, Schwann cell dedifferentiation, nerve myelination, and muscle reinnervation is necessary. This review highlights the contribution of functional NGCs and the influence of microscale biomaterial architecture on biological processes of nerve repair. Progressive NGCs with chemical molecule induction, heterogenous topographical morphology, electroactive, anisotropic assembly microstructure, and self-powered electroactive and magnetic-sensitive NGCs are also collected, and they are expected to be pioneering features in future multifunctional and effective NGCs.

Racial Disparity in Antibody Against A rare High Prevalence Antigen; (Anti-Inb)

Abstract Introduction/Objective Introduction: Ina antigen is very rare except in Iranian and Arab populations (10.6% and 11.8%, respectively). In 1973, Badkere et al. identified this antigen in about 3% of Indians from Bombay. Inb is a very high-prevalence antigen. It is prevalent in 99.9% of Caucasians and blacks, 96% of Indians and South Asians, and 90% of Iranians and Arabs. The Indian blood group system also has two other very high prevalence antigens: INFI and INJA. Indian blood group resides in CD44 glycoprotein that binds to hyaluronate of extracellular matrix. CD44 is an adhesion molecule in lymphocytes, monocytes, and other tumor cells, but its function in RBC is unknown. Ina and Inb are sensitive to proteolytic enzyme treatments and destroyed by disulfide bond-reducing agents 2-aminoethyl isothiouronium bromide (AET) and dithiothreitol (DTT). Methods/Case Report Case study: An 11-year-old female of South-East Indian descent with a history of intractable epilepsy was admitted for surgical treatment for epilepsy. Her antibody screen was positive, and her plasma reacted with all cells in PEG AHG except for the auto control. Ficin and DTT-treated cells weakened the reactivity. Suspecting a high-frequency antibody, the patient's plasma was tested against a series of cells in the rare donor cell inventory, including O Bombay cell and Inb-cell considering the patient's ethnicity. With Inb-negative cells, the plasma tested negative. All major alloantibodies from this rare donor cell were ruled out except for anti-C, anti-E, anti-K, and anti-S due to the availability of the rare cell. Results (if a Case Study enter NA) NA Conclusion Antigen Inb has a high prevalence in all populations. The rare phenotype In(b–) has been observed in approximately 2 of 700 Indian blood donors. A patient may be advised to undergo an autologous transfusion. Fortunately, the patient's procedures were uncomplicated, so a blood transfusion was unnecessary. Awareness on the part of blood bank staff regarding the variability of the blood group phenotype and the unpredictability of Anti-Inb may aid in improving patient care. To prevent further exposure, it is recommended that patients with rare antibodies carry an Antibody ID card indicating the rare antibody they possess.Inb antigen blood donors are under represented in the general donors pool. It is recommended to develop a systematic recruitment for Inb antigen donors

Prevalence and molecular basis of null blood group phenotypes in the Korean population: Analysis using a public database.

Null phenotypes are characterized by complete absence of all antigens within a blood group system and caused by null variants (e.g., nonsense, frameshift, initiation codon, and canonical splice site variants) in the genes encoding the antigens. Knowing the prevalence and molecular basis of null phenotypes is essential to establish a rare donor program, and the aim of this study was to reveal the prevalence and molecular basis of null phenotypes using the Korean Reference Genome Database (KRGDB) containing whole-genome sequences of 1722 Korean individuals. Population allele frequencies of null alleles in 39 blood group systems except ABO, MNS, Rh, Lewis, and FORS were obtained from the KRGDB. The prevalence of null phenotypes was calculated using Hardy-Weinberg equation. The prevalence of null phenotypes were estimated to be less than 0.001% in all blood group systems except JR and SID. The prevalence of the Jr(a-) and Sd(a-) phenotypes were estimated to be 0.0453% and 0.2323%, respectively. The most frequent null allele of the JR system was ABCG2*01N.01, accounting for approximately 85% of null alleles. Our approach using a public database allowed us to investigate the prevalence and molecular basis of null phenotypes in the Korean population, which will serve as a guide for establishing a rare donor program in Korea. Considering the clinical significance, Jr(a-) is an important null phenotype that should be typed in the Korean population, and molecular assays targeting the most frequent allele ABCG2*01N.01 may be useful in detecting this phenotype.

Real-World Feasibility of RH Genotype-Matched Red Blood Cells for Chronically Transfused Patients with Sickle Cell Disease

Introduction Most red blood cell (RBC) alloimmunization in sickle cell disease (SCD) is caused by sensitization to Rh (D, C, c, E, and e) and K antigens. Provision of serologic Rh and K-matched RBCs has reduced but not eliminated Rh alloantibody formation due to the high genetic variation within the RH loci in Blacks. Over 85% of patients with SCD, as well as Black donors needed to support CEK matching programs, have variant RHD or RHCE alleles that result in loss or alteration of Rh antigens. These variant Rh proteins are not detected by standard serologic tests, and thus, genetically matched RBCs may be necessary to prevent all Rh alloimmunization events. We previously used bioinformatic modeling to show that RH genetic matching was achievable for a cohort of ~200 patients of whom ~50% were chronically transfused, and represented 98 different RHD/RHCE allele combinations, with only 10 additional donations each weekday (~1050 Black donors/month) than required for serologic Rh and K matching. The real-world feasibility of providing RH genotype-matched RBCs to patients requiring regular transfusion has not been tested. Methods We performed a pilot study to evaluate the feasibility of providing RH genotype-matched RBCs from Black and Hispanic donors to non-Rh- and Rh-alloimmunized chronically transfused patients with SCD (1 to 18 years old). Black donor units at the blood center were first screened by serology, HEA BeadChip, and in-house RH SNP assays, and those selected for transfusion to study subjects had comprehensive RHD and RHCE genotyping. Data captured included RH genotypes of matched units identified, transfusion delays, unit age at time of transfusion, and pre-transfusion hemoglobin (Hb) and HbS levels. On-study values were compared to pre-study values obtained in the 6 to 12 transfusion visits prior to study enrollment. Results The study opened in February 2020. Due to the COVID-19 pandemic, donor center collections dropped to a nadir of ~500 Black donor units/month in 2020 but returned to ~1500 units/month currently, similar to pre-COVID numbers. For 14 participants (13 Black, 1 Hispanic), we transfused 327 RH genotype-matched units; 287 (88%) were exact RH genotype-matched (donor with identical genotype, homozygous for a matching RH haplotype, or RH allele match) and 40 (12%) were RH matched with the provision that RHD*RHD and *DAU0 and RHCE*ce and *ce48C are equivalent since no epitopes appear to differ between these alleles. No transfusion visits (n=183) were postponed due to the inability to identify RH genotype-matched units, including during the pandemic and national blood shortages that had a disproportionate impact on Black donations. Using individual patients as factors, ANOVA showed no statistically significant difference in unit age (days, Figure) or pre-transfusion Hb values between pre- and on-study transfusion visits. Although the goal maintenance pre-transfusion HbS levels varied between 30 and 50%, a statistically significant lower mean HbS on- (n=183) vs pre-study (n=139) (ANOVA F-ratio 15.4, p=0.000) (Figure) potentially suggests improved transfused RBC survival with RH genotype matching. This feasibility trial was not powered to detect a difference in alloantibody formation, but no Rh nor non-Rh antibody have been detected. Conclusion Recruitment of minority blood donors is a growing initiative nationally needed to support CEK matching. Our preliminary results suggest that genetic RBC matching at the RH loci may be feasible with Black and Hispanic donors. Donor center RH genotyping can facilitate transfusion of RH genotype-matched RBCs, improve allocation of minority and rare donor units and, at the same time, potentially improve patient care by avoiding Rh alloimmunization for individuals with SCD.

P‐BB‐73 | The American Rare Donor Program and Exports of Rare Blood Products, 2008–2022

P‐BB‐73 | The American Rare Donor Program and Exports of Rare Blood Products, 2008–2022

OA4‐AM23‐MN‐20 | The American Rare Donor Program: 25 Years of Providing Rare Blood to Alloimmunized Patients

OA4‐AM23‐MN‐20 | The American Rare Donor Program: 25 Years of Providing Rare Blood to Alloimmunized Patients

P‐BB‐28 | Determining the Validity of IgA Deficient Product Requests Submitted to the American Rare Donor Program from 2018 to 2022

P‐BB‐28 | Determining the Validity of IgA Deficient Product Requests Submitted to the American Rare Donor Program from 2018 to 2022

P‐IT‐11 | Novel Rare Donor Report to Identify Phenotypes When Sorting Red Blood Cell Segments for Testing

P‐IT‐11 | Novel Rare Donor Report to Identify Phenotypes When Sorting Red Blood Cell Segments for Testing

Clinically significant minor blood group antigens amongst South Indian donor population

Background and objectives: Distribution of blood group antigen varies among different races. It is important to know the distribution of these antigens so as to provide a donor database that aid in providing compatible blood units for patients with multiple alloantibodies. The present study was conducted to determine the distribution of clinically significant minor blood group antigens amongst the South Indian blood donors. Materials and methods: Blood samples were collected from healthy regular repeat voluntary blood donors of same ethnicity attending a tertiary care hospital in South Kerala. Clinically significant blood antigens of the ABO, Rh (D, C, c, E, and e), Kell, Duffy and Kidd blood group systems were determined. The ABO and Rh(D) grouping were performed by tube technique using monoclonal antisera. Column agglutination technique was used to phenotype Rh, Kell, Duffy and Kidd antigens. Results: Total 200 healthy repeat voluntary blood donors were enrolled in the study. Out of 200 donors, 92% were RhD positive. Among the Rh antigens, the e antigen was positive in 97.8 % and 100% among the Rh(D) positive and Rh(D) negative donors respectively. No E antigen was detected in RhD negative donors. Total 6 and 2 Rh phenotypes were observed among the Rh(D) positive and negative donors respectively. R1R1 and Rr were the most frequent phenotypes among the RhD positive and negative donors (47.28% and 93.75%) respectively. Among the Kell blood group antigens, K and Kpb antigens were present in 100% of our donors while in Duffy and Kidd system Fya and Jka were most predominant (89% and 87%) respectively. Conclusions: The findings of the present study would be helpful in developing in-house panel cells. Moreover, a rare donor registry of donors typed negative for a high-frequency antigen can be formulated. IMC J Med Sci. 2024; 18(1):004. DOI: https://doi.org/10.55010/imcjms.18.004 *Correspondence: Soonam John, Department of Transfusion Medicine, Government Medical College, Parippally, Kollam, Kerala,India. Email: johnsoonam@gmail.com

Rare blood group registry in India-current challenges and future perspectives.

Patients who require blood from rare blood group donors present great challenges even to the most advanced healthcare delivery system. It is most challenging to supply blood for a patient with an antibody to an antigen of high prevalence. The blood donor lacking the corresponding antigen would have an occurrence rate of less than one in 1,000. The International Rare Donor Panel was established in 1965, but since then there has been gross underrepresentation of South Asian countries, including India. There are several challenges to starting a rare blood group donor program in India that include technical, logistical, and administrative limitations. But the main limiting factors are poor availability of trained resources, lack of awareness, absence of antibody screening, inadequate number of laboratories with blood group genotyping facilities, and the decentralized nature of blood transfusion services. Despite that, there were several rare blood groups identified by Indian immunohematologists in the recent past. Recently, a transfusion genomic group has been established in collaboration with the clinical transfusion medicine specialists in India under the GUaRDIAN (Genomics for Understanding Rare Disease in India Alliance Network) initiative to address the domain of rare blood group genomics. Similarly, the National Institute of Immunohematology, Mumbai under the directive of the ICMR (Indian Council of Medical Research) has taken a step to start the RDRI (Rare Donor Registry of India). In this context, we explore the current challenges of setting-up a rare blood group registry in India and future goals from a developing nation's perspective.

Establishing a Regional Rare Blood Donor Registry in Uttarakhand, India

Background and Objectives: Uttarakhand, a state in northern India, is home to various local communities, including the Garhwali, Kumaoni, and Jaunsari. In addition, individuals from neighboring countries such as Nepal and Tibet reside in Uttarakhand for many years, resulting in a diverse population. However, currently, there is no regional registry for rare blood donors in this state. The aim of this study was to develop a rare donor registry in Uttarakhand which could in future become a part of the national rare blood donor registry. Methods: During the routine donation process, samples were taken from randomly selected O-typed blood donors who are residents of Uttarakhand. Seventeen monoclonal antisera included Rh (anti-D, anti-C, anti-c, anti-E, and anti-e), Duffy (anti-Fya and anti-Fyb), Kell (anti-K and anti-k), Kidd (anti-Jka and anti-Jkb), Lewis (anti-Lea and anti-Leb), M, N, S, and s (Ortho Diagnostics Pvt Ltd, Mumbai, India). Furthermore, four polyclonal antisera from our serum repository, Diego (anti-Dia), Indian (anti-Ina), Rh (anti-Cw), and anti-Gp-Mur were used for phenotyping. The study was financially aided by the Uttarakhand State Council of Science and Technology (UCOST), Dehradun, Uttarakhand, Government of India. Results: Over a period of 16 months (November 2021–February 2023), out of a total of 17,004 blood donations, O blood type donors accounted for 29.9% (5085/17,004) of the donors screened. Among these, 7.3% (374/5085) of the donors were from the interior and plain areas of Uttarakhand. Our study revealed a high prevalence of k and e antigens, with 96.7% and 92.5%, respectively. The least prevalent antigen was Rh (Cw), observed in only 0.5% of cases. We also identified rare blood antigens such as Diego, Indian, and Gp-Mur and compared our findings with other studies. Furthermore, we identified a donor with an H-deficient phenotype, specifically the Bombay blood group (Oho). Conclusion: We have successfully established a regional registry for rare blood donors in Uttarakhand, which will be valuable for managing complex transfusion scenarios in the future. Further, given Uttarakhand's proximity to China and Nepal, the presence of individuals from these countries aptly connects the fields of anthropology and transfusion medicine.

Use of selective phenotyping and genotyping to identify rare blood donors in Canada

The distribution of rare and specific red cell phenotypes varies between races and ethnicities. Therefore, the most compatible red cell units for patients with haemoglobinopathies and other rare blood requirements are most likely to be found in donors from similar genetic backgrounds. Our blood service introduced a voluntary question asking donors to provide their racial background/ethnicity. Results triggered additional phenotyping and/or genotyping. We analysed the results of additional testing performed between January 2021 and June 2022, and rare donors were added to the Rare Blood Donor database. We determined the incidence of various rare phenotypes and blood group alleles based on donor race/ethnicity. Over 95% of donors answered the voluntary question; 715 samples were tested, and 25 donors were added to the Rare Blood Donor database, including five k-, four U-, two Jk(a-b-) and two D- - phenotypes. Asking donors about their race/ethnicity was well received by donors, and the resulting selective testing enabled us to identify individuals with a higher likelihood of being rare blood donors, support patients with rare blood requirements and better understand the incidence of common and rare alleles and red blood cell phenotypes in the Canadian donor population.

Extended Phenotyping to Identify Blood Donors for an Institutional Rare Donor Registry

Abstract Background: Alloantibody formation to red cell antigens, sometimes seen in patients receiving multiple transfusions, are capable of causing hemolytic transfusion reactions when transfused with blood cells that are positive for the corresponding antigens. Providing them with red cells negative to these antigens becomes imperative. There is a need to have a pool of donors known to be negative for such antigens to provide blood units to such patients. Aim: The aim of the study is to identify rare donors in our population and register them for need-based blood unit collection for patients when phenotype-specific blood units are required. Methodology: Regular blood donors after consent were included for extended phenotyping for antigens c, C, e, E, K, k, Lea, Leb, Lua, Lub, P1, Kpa, Kpb, Jka, JKb, M, N, S, s, Fya, and Fyb by serological testing using monoclonal antisera. The phenotypes that were either negative for high-frequency antigens such as H, k, or multiple common antigen negative phenotypes were identified and enrolled as rare blood donors. Results: A total of 202 donors were completely phenotyped for the said 21 antigens. We identified 14 such donors, 7 of whom were high-frequency antigen-negative and 7 were multiple common antigen-negative phenotypes. The turnaround time for providing blood for patients requiring such units has drastically reduced with this initiative. A unit of such a rare phenotype was collected and shipped to Pune for a patient who required it within 24 h. Conclusion: Our findings highlight the need for a countrywide rare donor registry to coalesce the data from all centers with the facility for phenotyping. This will reduce the turnaround time of searching for donors for a particular phenotype, contributing to better patient care, and emergency management.

Mapping anticipated advantages and disadvantages of implementation of extensive donor genotyping: A focus group approach.

Current genotyping techniques allow typing of all relevant red cell, human leukocyte and platelet antigens in a single analysis. Even genetic markers related to donor health can be added. Implementation of this technology will affect various stakeholders within the transfusion chain. This study aims to systematically map the anticipated advantages and disadvantages of a national rollout of blood group genotyping of donors, which will affect the availability of rare donors and the implementation of an extensively typed blood transfusion policy. Two focus-group sessions were held with a wide representation of stakeholders, including representatives of donor and patient organisations. A dedicated software tool was used to collect the reflections of participants on genotyping for blood group antigens and extensive matching. Additionally, stakeholders and experts discussed various prepared propositions. All information collected was categorised. From 162 statements collected, 59 statements (36%) were labelled as 'hopes' and 77 (48%) as 'fears'. Twenty-six (16%) statements remained unlabelled. The statements were divided in 18 categories under seven main themes: patient health, genotyping, privacy issues and ethical aspects, donor management, inventory management and logistics, hospital and transfusion laboratory and general aspects. The discussion on the propositions was analysed and summarised. Stakeholders believe that a genotyped donor pool can result in a reduction of alloimmunization and higher availability of typed blood products. There are concerns regarding logistics, costs, consent for extended typing, data sharing, privacy issues and donor management. These concerns need to be carefully addressed before further implementation.

Red Cell Antibodies Against High Frequency Antigens, A Two Year Experience At A Regional Transfusion Institute

Objective: To assess the clinicohaematological presentation and outcome of patients with antibodies to high frequency antigen(HFA) in our setup.Study Design: Cross sectional study.
 Place and Duration of Study: Armed Forces Institute of Transfusion, Rawalpindi, from Jan 2016 to Jan 2018.
 Methodology: We diagnosed 29 cases of uncommon red cell antibodies including antibodies to HFA, in a span of two years (2016-2018). Information regarding patient’s age, diagnosis, transfusion history, incompatible cross match and history of pregnancy was obtained. Venous blood sample of 3ml was taken in EDTA for grouping, red cell phenotyping and Direct AntiGlobulin Test (DAT) and 5 ml venous blood was taken for Indirect Antiglobulin Test (IAT), antibody screening and identification. Tube method was used for forward and reverse blood grouping, DAT and IAT. Column Agglutination Technique (CAT) was used for antibody screening, identification and red cell phenotyping.
 Results: Out of a total of 29 cases, 24 (83%) were of anti H antibody (Bombay blood group). Rest of 5 (17%) included one each of anti Rh 17, anti Rh 29 (Rh null), anti P1Pk, anti-ENA/WRB and anti P antibodies. Anti H Lectin (Ulexeuropaeus) was used for confirmation of H antigen absence, while rest of antibodies were confirmed by IBGRL Bristol, UK.
 Conclusion: The sources of antigen negative blood are family members, rare donor registry, autologous donations and frozen blood banks. Finding compatible blood for patients with an antibody to HFA may be a challenge.

Mortality and morbidity in non-transfusable and transfusable patients: A systematic review and meta-analysis.

Mortality and morbidity in non-transfusable and transfusable patients: A systematic review and meta-analysis.

Phenotyping of clinically significant blood group antigens among the South Indian donor population

IntroductionData on the prevalence of clinically significant antigens (Rh, Kell, Kidd, Duffy, MNSs, Lewis, P and Lutheran) among the Indian donor population is sparse. ObjectiveThis prospective study was aimed at determining the prevalence of 21 clinically significant antigens for the first time in the South Indian donor population. MethodA total of 672 regular O group blood donors were enrolled for Rh (C,c, E, e) and Kell (K) antigens typing. Of these, 188 donors were typed for other clinically significant antigens (k, Kpa, Kpb, Jka, Jkb, Fya, Fyb, M, N, S, s, P1, Lea, Leb, Lua and Lub). ResultsAntigen frequencies were expressed in percentages. In our study, R1R1 and rr were the most common phenotypes among D+ and D- donors, respectively. Among the Rh antigens, the e antigen was expressed by 97.5% and 100% of D+ and D- donors, respectively. The K antigen was found in only 0.15% of donors. In the Duffy and Kidd blood group system, Fy (a+b+) and Jk (a+b+) were the most frequent phenotypes, respectively. In the MNSs blood group system, M+N+ and S-s+ were the most common phenotypes reported. The Le (a-b+) was found to be the phenotype with the highest prevalence in the Lewis blood group system. The Lu (a-b+) was the only phenotype found in the Lutheran blood group system. ConclusionKnowledge regarding the prevalence of antigens in a given population is essential in developing cost-effective in-house panels and a rare donor registry comprising donors typed negative for a high-frequency antigen or a combination of common multiple antigens.