ABO Blood Grouping Discrepancy and Crossmatch Incompatibility Due to Naturally Occurring Anti-M Antibody: A Case Report

This case report describes a 5-year-old female with antenatally detected multi-cystic dysplastic left kidney (MCDK) who was diagnosed with moderate patent ductus arteriosus (PDA) with left to right shunt and required shunt closure under general anesthesia. During the pre-operative workup, the patient’s blood group was found to be B Rh D+ve, but there were discrepancies in the reverse grouping suggesting the presence of an irregular antibody in the patient’s serum. Further immunohematological workup identified the presence of naturally occurring anti-M antibody. The patient did not have a history of previous surgery, ICU admission, transfusion, or any significant past or family history. This case highlights the importance of immunohematological workup and crossmatching in patients requiring blood transfusions and also the presence of naturally occurring antibodies (NOAs), which can complicate the transfusion process and increase the risk of hemolytic transfusion reactions (HTRs).