Hemolytic Transfusion Reaction due to Anti Jk Antibody, a Frequently Transient and Low-Titer Antibody Probably Not Detected in Pretransfusion Testing; A Case Report.

This case report describes the management of a middle-aged woman with abnormal uterine bleeding who developed Anti-Jk and Anti-M antibodies following multiple transfusions, illustrating the challenges in transfusion medicine. Despite initial negative antibody screening, repeat testing post-transfusion revealed these clinically significant antibodies, demonstrating the dynamic nature of alloimmunization. The case highlights the importance of the MNS and Kidd blood group systems in transfusion reactions, particularly the risk of delayed hemolysis with anti-Jk antibodies. Through serial antibody screening, advanced serological techniques, and close blood bank collaboration, antigen-negative blood was successfully provided for her urgent surgical needs. This report emphasizes the critical need for vigilant antibody monitoring in multitransfused patients, the value of interdisciplinary coordination, and the importance of ongoing clinician education to improve transfusion safety in complex cases.