Masquerading of mismatched blood transfusion by underlying autoimmune hemolytic anemia.

Mismatched blood transfusion due to immunohematological discrepancy is relatively uncommon and in most instances occurs due to Type IV blood group discrepancy which is the discrepancies between forward and reverse groupings. Here, we present a case of a 15-year-old girl with preexisting autoimmune hemolytic anemia (AIHA) who inadvertently received 3 units of wrongly matched packed red blood cell (PRBC), followed by severe intravascular hemolysis. On detailed immunohematological investigation, the patient was found to be autoimmunized and diagnosed with "mixed AIHA" and the patient's blood group was confirmed as "A" positive. Three units of group-specific "best match" PRBC was transfused under close observation without any adverse effect. This highlights the importance of carrying out both forward and reverse blood groupings to avoid mismatched blood transfusion.