Retrospective study about the frequency of irregular antibodies and the importance of those measurements in critically ill patients

Abstract

Introduction: Irregular antibodies are non-ABO alloantibodies that can cause hemolytic disease in fetuses and newborns, reduced red cell survival, and delayed hemolytic transfusion reaction (DHTR). DHTR may present with intravascular hemolysis and associated findings, including death. However, little is known about the frequency of irregular antibodies in critically ill patients. Methods: We used an electronic clinical transfusion management system to retrospectively assess all patients who underwent irregular antibody screening between January 2012 and November 2015. We collected information about age, sex, transfusion history, and type of irregular antibodies. Results: Screening for irregular antibodies revealed that 14 (1.8%) of 770 patients (male, n=11; female, n=3; mean age [±SD], 64.0±14.7 years) harbored irregular antibodies. Ten patients (1.3%) had clinically significant warm antibodies. Five patients had a history of transfusion and four did not. Information about transfusion was unavailable for the remaining five due to varying circumstances such as patient unconsciousness. Conclusion: Patients with irregular antibodies are not rare, and 14 (1.8%) of 770 patients in our ICU had them. As the history of transfusion in critically ill patients is often unknown, side effects of transfusion can be serious. Therefore, repeating irregular antibodies tests proactively may prevent side effects of transfusion, including DHTR.