1. Prepared by: Michael Mikula MD, MS
Reviewed by: Lorraine Blagg MA, MLS(ASCP)SBB

Clinical vignetteA pediatric patient was admitted for cytopenias and adenoviremia in the setting of secondary failure of bone marrow transplant. Of note, they have a history of a congenital autoimmune disease and hypogammaglobulinemia. They received a full unit of red blood cells for a hemoglobin of 7.0, which proceeded without incident. However, three hours after completing the transfusion, hematuria was reported. They experienced no symptoms and vitals were stable. Total bilirubin increased to 1.6, LDH was elevated at 431, and haptoglobin was low (<3). However, following transfusion, hemoglobin incremented to 8.0 and remained stable throughout the night. Of note, the patient is a genetic B positive and received A positive graft. They also have received previous transfusions in the past 3 months.

Post Transfusion results:Question: What is the most likely explanation of the patient's results?