ABO blood group phenotype in and around Delhi: A study from tertiary care hospital

Disha Arora*, Ankit Kaushik, D.S. Rawat, A K Mandal Department of Pathology, Vardhaman Mahavir Medical College and Safdarjung Hospital, New Delhi, India Background: ABO blood group shows marked geographical and racial variation. The study of regional ABO phenotype is extremely important for understanding the regional demand of rare blood groups and to tide over the massive demands in case of natural calamities or mass disaster. Methods: A retrospective study was carried out at Department of Blood Bank and Transfusion Medicine, VMMC and Safdarjung Hospital, Delhi from January 2013 to May 2014 constituting a total of 42,456 donors including both voluntary and replacement donation. The blood group antigens were determined using electromagnetic technology and the frequency is expressed in percentage. Results: B phenotype is most common phenotype constituting 39.84%of total donors, followed by O phenotype with 28.56%, A with 21.24% and AB with 10.56%. A total of 91.16% donors are Rh positive, while the rest are Rh negative. Conclusion: The ABO phenotype of Delhi and nearby regions is different from the western countries, South India and other parts of Asia. Thus this study aids in constructing a regional ABO phenotype data register for meeting regional transfusion demands. A-27 ABO phenotype in North India Annals of Pathology and Laboratory Medicine, Vol. 02, No. 01, Jan-Mar 2015 Introduction Human blood groups were discovered in 1900 and since then a variety of styles of terminology has been used to denote them. In 1980 the International Society of Blood Transfusion (ISBT) established a Working Party (later to become a Committee) organized red cell antigens into blood group systems. Landsteiner first described ABO blood group system in 1900. Alfred Von Decastello and Adriano Sturli discovered the fourth type AB, in 1902 [1] and since then many different blood group antigens have been described. The second type of blood group is rhesus system which is denoted as Rh positive and Rh negative depending on whether Rh antigen is present or absent on red cells. Although almost 400 blood group antigens have been reported, the ABO and Rh have been recognized as the major clinically significant blood group antigens. In blood transfusion practice, the ABO and Rh is the most important blood group system for blood group compatibility. [2] This is because A, B, and Rh D antigens are strongly immunogenic and upon stimulation elicit a strong antibody response and their alloantibodies can cause destruction of transfused red cells or induce hemolytic disease of newborn. [3] ABO antigens are also important in organ transplantation, resolving paternity disputes and for forensic purposes. Blood groups are known to have some association with diseases like duodenal ulcer, diabetes mellitus and urinary tract infection. The ABO blood group system is considered to be safe and cost effective in most transfusion except in case of multiple transfusions where extensive cross matching is required even for minor antigen to prevent alloimmunization. [4] ABO antigen is the integral part of cell membrane and has different biochemical composition despite similar basic antigen. [5] Blood group genes are inherited in a Mendelian manner and are mostly located on autosomes. Most of the blood group genes are expressed in a co-dominant manner. ABO blood group system is genetically determined. The particular alleles at specified gene locus in an individual constitute the genotype. Phenotype is the outward expression of the genotype and it shows a wide range of variation across races and geographical boundaries. Generally, O blood group is the most common, while AB group is the least common in a population. The antigenic profile of ABO blood group system in Indian population is quite different from Western countries and ABO antigenic profile is needed for proper match of demand and supply and to deal with emergency need in case of rare blood group. A regional donor data bank is of utmost importance in maintaining proper availability of blood for regional demand and for effective management of blood banks inventory, at a smaller local transfusion service or a regional or national transfusion service. [3] Materials and Methods A retrospective study was carried out at Department of Blood Bank and Transfusion Medicine, VMMC and Safdarjung Hospital, Delhi from January 2013 to May 2014 constituting a total of 42,456 donors including both voluntary and replacement donation. The selected blood donors were medically fit and belonged to age group between 18-60 years. A questionnaire comprising of name, age, sex, address, contact number and previous and current medical history was filled by donors and confirmed by examination. Weight, blood pressure, pulse rate, height and hemoglobin were also recorded. Most of the donors were from Delhi (India) and surrounding areas representing the north Indian population. The blood grouping was done by using fully automated and high output QWALYS 3 (DIAGAST FRANCE) that uses Erythromagnetic (EM) technology. The EM technology is based on magnetization of red blood cells. [6] ABO blood group determination was done concomitantly on the same machine by forward grouping by mixing antisera anti A, anti B and anti AB with donors RBC and results were confirmed by checking that corresponding antibodies are present in the test plasma using HEMALYS 1 A1, B which is a mixture of human red blood cells of known group A1 RH-1 or B RH -1. These controls used were sample of guaranteed phenotype of group A, B, AB and O.