FREQUENCY OF SUBGROUPS OF BLOOD GROUP “A” AND “AB” AMONGST THE BLOOD DONORS IN A REGIONAL CANCER INSTITUTE OF NORTH EAST INDIA AND ITS IMPORTANCE: A RETROSPECTIVE STUDY

Abstract

Introduction: ABO Blood group system was discovered by Karl Landsteiner in the year 1900 who classified the blood groups into A,B,AB and O on the basis of the presence or absence of the antigens A and B on the cell surface of Red blood cells.Further ,in the year 1911, Von Dungern and Hirszfeld divided the group A into A1 and A2 hence total of six blood groups A1,A2,B,A1B,A2B,O. Aim of the study is to find out the frequency of subgroups of A and AB Blood groups and its importance in transfusion practice.

Methods: A total of 5594 blood donors’ samples were collected in a one-year period who came to donate blood. Blood grouping was done by the conventional tube method both forward and reverse grouping. Sub grouping of A and AB was done by using the commercially available Lectin Anti A1 (Tulip diagnostics, Goa ,India) .Group A red blood cells which agglutinate with Anti A1 lectin are classified as subgroup A1,whereas which do not agglutinate are classified as A2.

Result: Out of total 5594 blood donors, 1354 belonged to group A and 413 constituted group AB. The percentage of A1 amongst the A blood group is 93.94% (1272) and A2 is 6.056 (82). The percentage of A1 amongst the AB blood group is 91.04% (376) and A2 is 8.95% (37)

Conclusion: The frequency of A1 subgroup is more in comparison to A2 in both A and AB blood groups amongst the blood donors. Identification and recording of subgroups is important in blood bank in respect to blood group discrepancy, blood transfusion reactions as well as Organ transplantation.