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.

Rapid and Reliable One-Step ABO Genotyping Using Direct Real-Time Allele-Specific PCR and Melting Curve Analysis Without DNA Preparation.

ABO genotyping is a molecular diagnostic technique important for transfusion and transplantation in medicine, and human identification in forensic science. Because ABO genotyping are labor intensive and time consuming, the genotyping cannot be firstly used to resolve the serological ABO discrepancy in blood bank. For rapid one-step ABO genotyping, we developed direct, real-time, allele-specific polymerase chain reaction (PCR), and melting curve analysis (DRAM assay) without DNA preparation. In DRAM assay, we used a special PCR buffer for direct PCR, a rapid RBC lysis buffer, white blood cells as template without DNA preparation, allele-specific primers for discriminating three ABO alleles (261G/del, 796C/A, and 803G/C), and melting curve analysis as a detection method. There was 100% concordance among the results of ABO genotyping by the DRAM assay, serologic typing, PCR-RFLP and PCR-direct sequencing of 96 venous blood samples. We were able to reduce the number of manual steps to three and the hands-on time to 12 min, compared to seven steps and approximately 40 min for conventional ABO genotyping using allele-specific PCR with purified DNA and agarose gel electrophoresis. We have established and validated the DRAM assay for rapid and reliable one-step ABO genotyping in a closed system. The DRAM assay with an appropriate number of allele-specific primers could help in resolving ABO discrepancies and should be valuable in clinical laboratory and blood bank.

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

INTRODUCTION: The ABO system is the most important of all blood group systems in transfusion practice. ABO grouping is a simple, accurate, and precise procedure and to be considered valid, the results of cell grouping and serum grouping should agree. The aim of this study was to assess the cause of discrepancies and its implication in transfusion practice. METHODS: This study was performed between January 2010 and May 2013. We analyzed ABO discrepancies which were detected serologically in blood donors, where a result of cell grouping and serum grouping was discordant. Confirmation of subgroups was carried out by adsorption and elution technique. Saliva of these donors was also tested for A, B, and H antigens by inhibition tests. RESULTS: Twenty-eight blood group discrepancies were observed in 44 425 blood groups tested during the study period, thus giving an overall frequency of 0.06%. Technical errors leading to blood group ABO discrepancy were noticed in five cases. Sample-related problems that affect red-cell testing were observed in twenty cases, and the most common cause of ABO discrepancies in this category was subgroups of A and B. ABO discrepancies that affect the serum testing included the presence of additional antibodies other than anti-A and anti-B. CONCLUSION: It is imperative to recognize discrepant results and resolve them. Correct blood typing and labeling of an individual are essential to prevent ABO incompatibility.

Six Years' Experience Performing ABO Genotyping by PCR-direct Sequencing / 대한수혈학회지

BACKGROUND: ABO genotyping is essential for resolving ABO grouping discrepancy and for determinating ABO subgroups. Most clinical samples, including suspected inherited subgroups and acquired variant phenotypes, can be determined by PCR-sequencing of exons 6 and 7 in the ABO gene. Here, we describe our six years' experience performing ABO genotyping by PCR-direct sequencing. METHODS: We conducted a retrospective investigation of serological and genotypical data from 205 samples (158 patients and 47 of their family members) of patients who were referred to the Molecular Genetics Laboratory at Chonnam National University Hwasun Hospital for ABO genotyping between January 2007 and July 2012. ABO genotyping was performed on all samples with PCR-direct sequencing of exons 6 and 7 in the ABO gene; the standard serologic tests were also performed. RESULTS: The frequency of phenotypes consistent with their genotypes was 70.8% (112/158 cases) and the A2B3 phenotype with the cis-AB01 allele was the most common (31.0%, 49 cases) among them. The frequency of phenotypes inconsistent with their genotypes was 29.1% (46/158 cases) and the A1B3 phenotype was the most frequently recovered case (5.1%, 8 cases). Family study showed differential phenotype expression depending on the co-inherited ABO allele in five families with the B306, cis-AB01, Ael02, Aw14, or B305 allele and also showed a typical inheritance of a chimera with A102/B101/O04. CONCLUSION: We propose that ABO genotyping using PCR-direct sequencing is useful for the resolution of ABO discrepancies and for the investigation of ABO subgroups based on six years' experience. In addition, family study for analysis of phenotypic patterns of ABO subgroups is also crucial to ABO genotyping.

Six Years' Experience Performing ABO Genotyping by PCR-direct Sequencing / 대한수혈학회지

BACKGROUND: ABO genotyping is essential for resolving ABO grouping discrepancy and for determinating ABO subgroups. Most clinical samples, including suspected inherited subgroups and acquired variant phenotypes, can be determined by PCR-sequencing of exons 6 and 7 in the ABO gene. Here, we describe our six years' experience performing ABO genotyping by PCR-direct sequencing. METHODS: We conducted a retrospective investigation of serological and genotypical data from 205 samples (158 patients and 47 of their family members) of patients who were referred to the Molecular Genetics Laboratory at Chonnam National University Hwasun Hospital for ABO genotyping between January 2007 and July 2012. ABO genotyping was performed on all samples with PCR-direct sequencing of exons 6 and 7 in the ABO gene; the standard serologic tests were also performed. RESULTS: The frequency of phenotypes consistent with their genotypes was 70.8% (112/158 cases) and the A2B3 phenotype with the cis-AB01 allele was the most common (31.0%, 49 cases) among them. The frequency of phenotypes inconsistent with their genotypes was 29.1% (46/158 cases) and the A1B3 phenotype was the most frequently recovered case (5.1%, 8 cases). Family study showed differential phenotype expression depending on the co-inherited ABO allele in five families with the B306, cis-AB01, Ael02, Aw14, or B305 allele and also showed a typical inheritance of a chimera with A102/B101/O04. CONCLUSION: We propose that ABO genotyping using PCR-direct sequencing is useful for the resolution of ABO discrepancies and for the investigation of ABO subgroups based on six years' experience. In addition, family study for analysis of phenotypic patterns of ABO subgroups is also crucial to ABO genotyping.