A Review on Discrepancy of ABO Blood Grouping, Distribution of Causes in Iran and the World, Resolving Methods

ABO blood grouping is the most important test that should be examined before blood transfusion. Transfusion of ABO incompatible blood leads to acute hemolytic reactions, malignant disease and in severe and uncontrolled cases might cause death. Direct or forward blood grouping or cell typing (i.e. investigation of antigens on erythrocytes surface) and indirect grouping or reverse typing (i.e. investigation of serum antibodies) are the most common tests to determine blood groups in laboratory. Interpretation and compatibility of the results from blood grouping tests (cell typing and reverse typing) is a crucial step to decide and perform blood transfusion. In case of incompatible results of direct and indirect blood grouping, additional tests must be performed before reporting the results and in emergency blood transfusion situations O+ RBCs should be used. In this manuscript we reviewed and summarized factors involvedin ABO blood group discrepancies. We studied reports in this context in Iran and the world and we compared the most frequent incompatibility factors in Iran in comparison to the rest of the world. Finally, we suggested plausible methods which could be taken into account to lower the risk of incompatible blood transfusion in Iran. Technical and clerical errors in Iran and the world, respectively, are reported to be the most common cause of ABO discrepancy. This result indicates different nature of ABO discrepancy factors between Iran and other countries. Understanding these differences is the very first step to improve blood donation and transfusion procedures locally and that requires long-term extensive domestic investigations.