Analysis of ABO subgroups which result in ABO discrepancies in Iranian blood donors

The ABO blood group system plays a vital role in the blood transfusion and transplantation medicine [ [1] Hosseini‐Maaf B. Hellberg Å. Chester M.A. Olsson M.L. An extensive polymerase chain reaction–allele‐specific polymorphism strategy for clinical ABO blood group genotyping that avoids potential errors caused by null, subgroup, and hybrid alleles. Transfusion. 2007; 47: 2110-2125 Crossref PubMed Scopus (44) Google Scholar ]. It consists of the major A, B, O alleles and many of subtypes with weak expression of A or B antigens on red blood cells. The results of both forward and reverse ABO typing are necessary for ABO blood group typing, as they are both necessary for interpreting the results [ [2] Arumugam P. Hamsavardhini S. Ravishankar J. Bharath R. Resolving ABO discrepancies by serological workup‐an analysis of few cases. Int J Res Med Sci. 2017; 5: 893-900 Crossref Google Scholar ]. ABO discrepancies may be due to technical or human errors, weak subgroups, the transient expression of antigens in some disease like carcinomas and mixed-filled agglutination after massive or chronic transfusion [ 3 Kaur G. Kaur P. Basu S. Kaur R. Blood group discrepancies at a tertiary care centre–analysis and resolution. Int J Lab Hematol. 2014; 36: 481-487 Crossref PubMed Scopus (18) Google Scholar , 4 Meny G. Recognizing and resolving ABO discrepancies. Immunohematology. 2017; 33: 76-81 Crossref PubMed Google Scholar , 5 Storry J.R. Condon J. Hult A.K. Harrison A. Jørgensen R. Olsson M.L. An age‐dependent ABO discrepancy between mother and baby reveals a novel A weak allele. Transfusion. 2015; 55: 422-426 Crossref PubMed Scopus (7) Google Scholar ]. The incidence of ABO discrepancies among blood donors was reported from 0.02 % to 0.06 %, Also the ABO subgroups are considered the most common cause of ABO discrepancies [ 3 Kaur G. Kaur P. Basu S. Kaur R. Blood group discrepancies at a tertiary care centre–analysis and resolution. Int J Lab Hematol. 2014; 36: 481-487 Crossref PubMed Scopus (18) Google Scholar , 6 Sharma T. Garg N. Singh B. ABO blood group discrepancies among blood donors in Regional Blood Transfusion Centre GTB Hospital, Delhi, India. Transfus Apher Sci. 2014; 50: 75-80 Abstract Full Text Full Text PDF PubMed Google Scholar , 7 Makroo R.N. Kakkar B. Agrawal S. Chowdhry M. Prakash B. Karna P. Retrospective analysis of forward and reverse ABO typing discrepancies among patients and blood donors in a tertiary care hospital. Transfus Med. 2019; 29: 103-109 Crossref PubMed Scopus (10) Google Scholar ]. Weak ABO subgroups are categorized as type II (Weak/missing antigen) or type IV (due to presence of Anti–A1) ABO discrepancy [ [8] Jain A. Gupta A. Malhotra S. Marwaha N. Sharma R.R. An ABO blood grouping discrepancy: Probable B (A) phenotype. Transfus Apher Sci. 2017; 56: 459-460 Abstract Full Text Full Text PDF PubMed Scopus (3) Google Scholar ]. Mistyped A and B weak blood group as O and B(A) as cisAB and AxB during routine serologic tests can have serious consequences, such as hemolytic adverse transfusion reactions [ [9] Jiao L.X. Zhang J.Y. Chen L. Yu X.L. Han Y. Yang F. et al. Gene identification of rare B (A) blood group. Transfus Apher Sci. 2017; 56: 855-857 Abstract Full Text Full Text PDF PubMed Scopus (2) Google Scholar ].