Evaluation of Anti-A and Anti-B Antibody Titres in Group O Blood Donors Using Saline Agglutination and Indirect Antiglobulin Methods: A Cross-Sectional Study from South India

Background

High-titre anti-A and anti-B antibodies in group O plasma identify “dangerous universaldonors” who may cause passive haemolytic reactions. Saline rapid-spin agglutination mainly detects IgMantibodies, whereas the indirect antiglobulin test (IAT/Coombs’ phase) also detects clinically relevant IgGantibodies. Comparative data from South India are limited.