Comparative scores of ABO and Rh hemagglutination reactions

Background: Blood group determination is done by the slide test and tube test. Grading/scoring of hemagglutination reactions is performed through the naked eye and microscopy to detect spurious (false positive and negative) reactions. Objectives: In our observational study, comparative scoring of ABO and Rh hem-agglutination reactions was done based on degree of hemolysis and agglutination through the macroscopic and microscopic technique. Materials and Methods: The determination of blood group of 209 participants was done by the porcelain slide method using commercially prepared antisera (manufactured by TULIP DIAGNOSTICS (P) LTD.) containing anti-A, anti-B, and anti-D monoclonal antibodies followed by scoring/grading based on degree of hemolysis and red blood cell clumping. The data were statistically analyzed using the Chi-square test and Z -test of proportion. Results: ABO hemagglutination reactions showed significantly higher score ([A-Macro Z = 7.153, Micro Z = 4.65] [B-Macro Z = 11.17, Micro Z = 21]) (Z >2.5, P < 0.001) than Rh hemagglutination reactions. B hemagglutination reactions showed insignificantly higher score (B-Macro Z = 1.29, Micro Z = 1.816) (Z <1.95, P < 0.05) than A hemagglutination reaction. Conclusion: ABO hemagglutination reactions showed significantly higher score than Rh hemagglutination reactions as ABO system agglutinin are pentavalent (immunoglobulin M) binding 10 agglutinogens while that of Rh system are bivalent binding 4 agglutinogens. B hemagglutination reactions showed insignificantly higher score than A hem-agglutination reaction which required further evaluation.