Blood group discrepancies at a tertiary care centre - analysis and resolution

Serological and molecular analysis of the B(A) subtype in China-A systematic review

OBJECTIVE

To study the serological and molecular biological characteristics of the B(A) subtype and its geographical distribution in China through case discussion and systematic review.

METHODS

A case of the B(A)02 subtype previously found in our laboratory was retrospectively analysed. The distribution characteristics and specific serological and genotypic characteristics of the B(A) subtype in China were systematically evaluated by searching four major Chinese databases.

RESULTS

In a previous case of an abnormal blood group, both the proband and her father were found to be genotype B(A)02/O02, while the mother was normal type B. After a systematic search, irrelevant studies were screened out, and 88 studies were included for analysis. The results showed that the B(A)04 subtype was significantly more frequently reported in the north than in the south, while the B(A)02 subtype was predominant in the southwest. The A antigen of the B(A)02 subtype reacts with monoclonal anti-A reagents in a wide range, while the A antigen of the B(A)04 subtype has a weak agglutination intensity of less than or equal to 2+.

CONCLUSION

The results showed that the B(A) subtype has specific characteristics in the Chinese population, and this study further enriched the serological and molecular biological characteristics of the B(A) subtype.

Immunohematological challenges in COVID infected patients

BACKGROUND

Several autoimmune disorders have been reported to be related with COVID infection. In continuation to these autoimmune phenomenon, autoimmune hemolytic anaemia (AIHA) also has been noted in COVID infected patients. The aim of the study was to find out the prevalence of red cell alloimmunization, ABO discrepancy and positive direct antiglobulin test (DAT) results in COVID infected patients hospitalised in a tertiary care centre in North India.

METHODOLOGY

This was a retrospective observational study done from July 2020 to June 2021. All symptomatic patients admitted to ICU tested positive for SARS CoV-2 whose blood samples were received in the immunohematology laboratory of department of Transfusion Medicine for determination of blood group and issue of packed red cells, and found to have positive antibody screen, blood group discrepancy and positive DAT results, were included in the study.

RESULTS

A total of 10,568 tests were run, out of which 4437 were for determination of blood group, 5842 were for antibody screen and 289 were for direct antiglobulin test. Included in this study were 146 patients who either had blood group discrepancy, or had a positive antibody screen or had a positive DAT. Out of 115 positive antibody screen, 66 patients had only alloantibodies, 44 patients had only autoantibodies while only 5 patients had both auto as well as alloantibodies. Total number of positive DAT cases was 50 (50/289 = 17.3 %). There were 26 ABO discrepancies (26/4437 =0.58 %) found.

CONCLUSION

Our results also indicate that there is rise in rate of alloimmunization and DAT positivity among COVID patients.

Incidence of acute haemolytic transfusion reaction among ABO-incompatible recipients transfused with A3 blood: A case series

BACKGROUND AND OBJECTIVES

ABO antigens are among the most immunogenic, but the haemolytic risks of ABO incompatibilities involving a donor with a weak ABO phenotype are little documented.

MATERIALS AND METHODS

This retrospective case series assessed the incidence of acute haemolytic transfusion reaction (AHTR) among ABO-incompatible recipients of A3 blood in Québec (Canada). Transfusion safety officers reported laboratory AHTR indicators measured ≤24 h pre- and post-transfusion. Because the AHTR case definition of Québec's Hemovigilance System (QHS) leaves significant room for clinical judgement, a two-step approach was used to assess potential cases: Step 1 consisted in a highly sensitive-but unspecific-initial screen that identified all candidate cases per QHS case definition, and Step 2 consisted in a detailed review of candidate cases by two haematologists.

RESULTS

Nine donors initially typed as Group B (N = 1) or O (N = 8) were subsequently found to display an A3 B or A3 O phenotype. Eighty-one recipients received ABO-incompatible blood, including 53 (65.4%) with interpretable data. Of these, 29 (54.7%) were classified as candidate cases after Step 1. Following Step 2, no conclusive evidence of AHTR was found: Abnormal pre- versus post-transfusion changes appeared modest, within normal range, insufficient to ascertain AHTR, or were consistent with a pre-existing condition unrelated to AHTR. Two candidate cases had a QHS-reported transfusion reaction; both were unrelated to AHTR.

CONCLUSION

In this case series, no conclusive evidence of serious AHTR was found among ABO-incompatible recipients who were inadvertently transfused with A3 blood.

ABO blood group discrepancies in blood donor and patient samples at a tertiary care oncology centre: analysis and serological resolution

INTRODUCTION

In serological testing, determination of ABO grouping requires both antigen typing for A and B antigens and screening of serum or plasma for A and B antibodies. Lack of corroboration between the results of the cell and serum groupings identifies a discrepancy. Analysis of ABO blood group discrepancies was performed to determine the incidence of these discrepancies among healthy blood donors and oncology patients.

MATERIALS AND METHODS

ABO discrepancies found during testing of blood samples from blood donors and patients in an oncology centre in the period from January 2015 to December 2018 were analysed. ABO blood grouping was performed using the column agglutination test. Detailed serological workups were carried out to resolve discrepancies.

RESULTS

During the study period, a comprehensive analysis was conducted on a large dataset comprising 76,604 blood donor samples and 134,964 patient samples. Of these samples, 117 ABO discrepancies were identified with 13 occurring in blood donor samples and 104 in patient samples. The results demonstrated discrepancies caused by weakened/missing antibodies, weakened/missing antigens, panagglutination and miscellaneous factors in the blood donor samples, with percentages of 0%, 38%, 8%, and 31%, respectively. In patient samples, the percentages were 24%, 27%, 26%, and 15%, respectively.

CONCLUSION

Weakened/missing antigen discrepancies were the prevalent type in both blood donor and patient samples. For accurate blood group reporting and management of transfusion needs of patients, a complete serological workup is vital to resolve any blood group discrepancies.

Analysis of Blood Group Discrepancy in Healthy Blood Donors at a Tertiary Care Referral Hospital from Eastern India: A Retrospective Study

Objective  ABO typing constitutes cell grouping and serum grouping. The discrepancy may arise in ABO typing due to a mismatch in cell grouping and serum grouping. It may be due to technical errors, missing or weak ABO antibodies (type I), weak ABO subgroups (type II), Rouleaux formation (type III), or other miscellaneous reasons (type IV). This study was carried out to determine the prevalence and cause of ABO blood group discrepancy in donor samples at our center.

Methods  A retrospective study of ABO blood group typing of blood donors was conducted at our center. The blood group typing was routinely performed using gel cards and a microcentrifuge system (Tulip Diagnostics(P) Ltd, Goa, India). If any discrepancy in ABO typing was noted, the test was repeated using the conventional tube technique. After sorting clerical/technical error, the causes of discrepancy were analyzed and resolved using anti-A ₁ , anti-H, anti-AB, and other immunohematological tests like antibody screening and identification, saliva inhibition test, adsorption-elution studies.

Results  A total of 12,715 (98.6% males and 1.4% females) donor samples were tested. The number of ABO discrepancies detected were 15 (0.12%). The discrepancies were characterized as type I (6 cases; 40%), type II (1 case; 6.7%), type III (0 cases; 0%), and type IV (8 cases; 53.3%). Three cases, each of anti-M and anti-Le ^b , were detected in the study population. A single case of A ₃ , a subgroup of A blood group, was found during the study.

Conclusion  The prevalence of ABO group discrepancy was 0.12% at our center. Discrepancy arising during ABO typing of blood donor must be resolved before reporting ABO blood group to minimize the recipient's chances of transfusion reaction. The serum grouping is equally crucial as cell grouping for reporting the ABO group of an individual.

Analysis of ABO grouping discrepancies among patients from a tertiary hospital in Korea

BACKGROUND

Accurate ABO typing is essential for preventing ABO incompatibility reactions. However, the causes of ABO grouping discrepancy has not been sufficiently studied, and it may vary among different ethnic populations. Thus, the aim of this retrospective study was to investigate the causes of ABO discrepancy in the East Asian population.

MATERIALS AND METHODS

A retrospective observational study on ABO typing discrepancy among patients in a tertiary hospital was carried out using the electronic medical record database of Samsung Medical Center (Seoul, Korea) between July 2016 and May 2019.

RESULTS

ABO grouping was performed on 551,959 blood samples during the study period; 1468 events of serologic ABO discrepancy were determined from 1334 (0.24 %) samples. A total of 134 samples (0.02 %) presented multiple causes of ABO discrepancy. Weak/missing serum reactivity (594, 40.5 %) was the most frequent reason for ABO discrepancy, followed by extra serum reactivity (370, 25.2 %), weak/missing red cell reactivity (267, 18.2 %), mixed-field red cell reactivity (176, 12.0 %), and extra red cell reactivity (61, 4.2 %). In the category of weak/missing red cell reactivity, ABO subgroup was the most common reason, and using ABO genotyping, 26.2 % of the cases genotyped were found to be related to the cis-AB allele.

CONCLUSIONS

Our results suggest that the incidence and cause of ABO typing discrepancies vary among institutes and ethnic groups. Our data helps to better understand and facilitate the resolution of ABO typing discrepancies in patients.

Retrospective analysis of molecular biology mechanism of ABO blood group typing discrepancy among blood donors in Jinan blood station

BACKGROUND

To accurately identify ABO blood typing in pre-transfusion testing is very important to ensure blood transfusion safely, which is a major responsibility of blood station.

METHODS

Eighty-one blood donors samples with ABO blood group typing discrepancy was collected among 61952 donor samples in our blood station from January 2019 to July 2020. Blood group serological method was used to detect ABO blood group. DNA Sequencing was used to determine the genotype. The antibody screening test detects antibodies other than ABO.

RESULTS

In total, 61,952 donor samples were analysed for ABO typing discrepancies. The incidence among blood donors was 0.13% (81/61952). The most common reason of ABO typing discrepancies was due to specific antibody or non-specific agglutination (54.32%, 44/81), mainly anti-M antibody, cold autoantibody, anti-D antibody, anti-N antibody and anti-Lea antibody. The major cause of forward typing discrepancies among blood donors was ABO subgroups (25.93%, 21/81), including 10 cases of A subtype (1 case of A2, 2 cases of A3, 2 cases of Ax, 3 cases of AxB, 1 case of Ael, 1 case of Ahm), 6 cases of B subtype (2 cases of B3, 1 case of Bel, 3 cases of AB3), 2 cases of B subtype (A), 1 case of cisAB, and 2 cases of acquired B. The serum antibody was weakened in 16 cases (19.75%).

CONCLUSIONS

The blood types should be correctly identified by combining serology with gene sequencing to ensure the safety of clinical blood transfusion, when the forward and reverse typing discrepancies among the blood donors.

An algorithmic approach to serological work-up of ABO sub-groups which present as ABO discrepancies in resource constraint settings

BACKGROUND

ABO subgroups or weaker variants of A or B are group A or B subjects whose erythrocytes give a weak or negative reaction serologically with anti-A or Anti - B antisera respectively. Occurrence of these subgroups may lead to an ABO discrepancy which often puts transfusion services in a quandary. ABO subgroups which present as ABO discrepancies can be missed if reverse grouping is not performed.

AIM

This study was planned to estimate the prevalence of different subgroups which can present as an ABO discrepancy in Indian population, and provide an insight to transfusion services for identification of subgroups serologically.

MATERIALS AND METHODS

A cross-sectional, analytical study was performed at a tertiary healthcare based blood bank on whole blood donors and patients from January 2017 to July 2018. All suspected type II and Type IV (with Anti-A1) ABO discrepant samples were projected to an algorithmic testing process, to confirm discrepancy and then narrow down to the probable subgroup.

RESULTS

A total of 33 subgroup discrepancies; 26 of A group and 7 of B group were identified out of 73,380 patient and 35,279 donor samples tested for blood grouping. Following the algorithm, the overall prevalence of weak subgroups which can present as an ABO discrepancy was found to be 1 in 3293 or 0.03% in our population by serological testing. Out of the discrepancies caused by subgroups, the prevalence of subgroups of A were 0.0101%, 0.0018%, 0.0009%, 0.0027%, 0.0027% and 0.0018% for A2 with anti-A1, A3, Aend, Ax, Am and Ael respectively while those of B were 0.009%, 0.0009%, 0.0009% and 0.009% for B3, Bx, Bm and Bel respectively.

CONCLUSION

Algorithmic approach for resolution of ABO discrepancies caused by subgroups helps in identifying the subgroup which is important because these individuals may be mistyped as group O individuals.

Establishing Blood Group Genotyping to Resolve ABO Discrepancies in Iran

ABO discrepancies are recognized when the reactions obtained in the forward type do not "match" the reactions obtained in the reverse type. Discrepant results are often caused by a variant ABO gene. Molecular analysis is required to confirm the type of subgroups and discrepancy. In this study ABO genotyping was performed on a series of blood donors and patients to determine their definite blood groups. We examined 100 samples with ABO discrepancies from blood donors and patients referred to Tehran Blood Transfusion Center between October 2015 and August 2016. ABO genotyping was performed on all samples with allele specific PCR for differentiation of A, B and O alleles. Exon 6 and 7 of ABO gene were sequenced to confirm the results. The genotyping of donor/patients samples with discrepant results of ABO blood typing consisted of 61 cases of A₂ and A₂B, 3 cases of B 302 and 4 cases of Aw06. Genotyping of 6 samples that had extra antibody in their serum (AB blood group) confirmed the cell type reaction results. 6 samples that had shown a very weak reaction with anti-AB (similar to O blood group) and had no anti-A in their serum were genotyped as O ₁ O ₂. Blood group genotyping laboratory provides an efficient service for evaluation of ABO discrepancies and resolve the problems encountered in serology reactions.

A novel Bruton tyrosine kinase gene variation was found in an adult with X-linked agammaglobulinemia during blood cross-matching prior to surgical operation

AIMS/OBJECTIVES

To investigate the underlying molecular mechanism of the patient's ABO typing discrepancy.

BACKGROUND

ABO typing discrepancy was frequently seen in patients due to different causes. In this study, ABO typing discrepancy was found in a 24-year-old man with arthralgia, whose forward ABO grouping was O and reverse ABO grouping was AB. Primary immunodeficiency disease was speculated in this patient, especially X-linked agammaglobulinemia (XLA).

METHODS

Immunoglobulins of all isotypes were detected using a specific protein analyser. Lymphocyte subgroups were analysed by flow cytometry. All 19 exons and boundaries of BTK gene were amplified by polymerase chain reaction (PCR), and all PCR products were sequenced by a DNA analyser. BTK protein in the leukocytes and platelets was detected by Western blot.

RESULTS

No B lymphocytes could be detected in the peripheral blood of the patient. A novel BTK gene variation, c.817G>T, in the exon 9 of BTK gene was discovered. No BTK protein expression could be detected in the leukocytes and platelets of the patient.

CONCLUSIONS

XLA could be occasionally discovered by ABO typing discrepancy in some cases because of the deficiency of reciprocal IgM anti-A and/or anti-B antibodies in the serum of the patient. Humoral immunodeficiency is one of the causes of ABO typing discrepancy.

Rapid rare ABO blood typing using a single PCR based on a multiplex SNaPshot reaction

BACKGROUND

ABO subgroups would be considered when discrepancies in ABO grouping occur. Serological methods including adsorption-elution test, salivary ABH inhibition test, and anti-A1 (lectin) saline method could be used. However, these serological methods are laboring and obscure. Therefore, reliable and affordable method to assess the ABO subgroups is of particular interest.

METHODS

To solve this problem, the multiplex SNaPshot-based assays were designed to determine rare A and B subgroups. Primers used as probes for determination of rare ABO blood groups known in Taiwanese population were designed. Many ABO subtype samples were used to validate the accuracy and reproducibility of our SNaPshot panel.

RESULTS

A panel of primer probes were successfully designed in determining 8 SNP sites (261, 539, 838, 820, 745, 664, IVS6 +5, and 829 in exon 6 and 7) for A phenotype and 6 SNP sites (261, 796, IVS3 +5, 247, 523, and 502 in exon 2, 6 and 7 and intron 3) for B phenotype. SNaPshot analysis for defining blood group A alleles (A₁, A₂, A₃, A_m and A_el) and blood group B alleles (B₁, B₃, B_w and B_el) was therefore available.

CONCLUSION

SNaPshot analysis could be used in reference laboratories for typing known rare subgroups of A and B without DNA cloning and traditional sequencing. Moreover, this method would help to construct databases of genotyped blood donors, and it potentially plays a role in determining fetal-maternal ABO incompatibility.

Discrepancy in Blood Grouping: Subgroups of B-Challenges and Dilemma

Though not very frequent, blood group discrepancies are of common occurrence which must be promptly resolved for safe transfusion practices. Blood group discrepancy is defined as the non-corroboration between cell grouping and serum grouping. Variable erythrocyte antigenic expressions (qualitative and/or quantitative difference) owing to allelic heterogeneity, give rise to subgroups. Problems during blood grouping due to weakened expression of antigens are a rare cause for ABO discrepancies. Of note, subgroups of 'B' with decreased expression of the B antigen are of very rare occurrence in the general population. Serologically, the variants of 'B' can be classified into B₃, B_x, B_m and B_el. Serological confirmation of such subgroups requires special immuno-haematological procedures. The current study reports 3 cases of subgroups of B (2 cases of B_m and 1 case of B_w) detected at our centre. It is important to detect and resolve discrepant ABO grouping results so as to prevent ABO mis-match transfusions. Such individuals should also be pre-emptively informed of their respective blood donor and transfusion recipient status, as well.