Diagnosis of Immunodeficiency Presenting as ABO Grouping Discrepancy: Two Case Reports

The correct determination of ABO grouping is of paramount importance in blood transfusion. The concordance between forward grouping and the reverse grouping tests ensures the validation of blood grouping and transfusion safety. Grouping difficulties are sometimes encountered, including inconsistency due to a reactive default of the plasma test characterized by the observation of a weak or absent agglutination reaction with the A or B red blood cell tests. This makes the interpretation of blood grouping impossible. To overcome this reactive ambiguity and ensure a valid result, other techniques such as adjusting temperature, modifying the antigen–antibody ratio, and using proteolytic enzymes like Papain are necessary. This work details two cases of discordance between the forward grouping and the reverse grouping tests, the investigation of which facilitated the diagnosis of an immune deficiency.