Retrospective analysis of forward and reverse ABO typing discrepancies among patients and blood donors in a tertiary care hospital

SUMMARY Objective The aim of our study was to determine the incidence and causes of ABO typing discrepancies among patients and blood donors at our centre. Background An accurate interpretation of the ABO blood group of an individual is of utmost importance to ensure patient safety and good transfusion practices. Methods A retrospective observational study was carried out in the Department of Transfusion Medicine in our hospital from March 2013 to December 2015. Records of all patient and blood donor samples were retrieved and analysed for ABO typing discrepancies. Results In total, 135 853 patient and 62 080 donor samples were analysed for ABO typing discrepancies. The incidence among patients and blood donors was found to be 0·1% (138/135853) and 0·02% (14/62080), respectively. The mean age for patients and blood donors was 48·4 and 29·2 years, respectively. The most common cause of ABO typing discrepancies was due to cold autoantibodies among the patients (50·7%) and blood donors (57%) causing discrepant results in reverse typing. The various other causes of reverse typing discrepancies among patients were weak/missing antibody (25·4%), cold‐reacting alloantibody (4·3%), warm autoantibody (2·2%), anti‐A1 antibody (2·2%), Bombay phenotype (1·5%), transplantation (0·7%) and rouleaux (0·7%), whereas in blood donors, the causes were cold‐reacting antibody (7%) and weak antibody (7%). The major cause of forward typing discrepancies among patients (12·3%) and blood donors (29%) was ABO subgroups. Conclusion The resolution of ABO typing discrepancy is essential to minimise the chance of transfusion of ABO‐incompatible blood.