USMLE Question of the Week

Mechanisms of Acute Transfusion Reactions

In Episode 38 of Med School Question of the Week for USMLE, Faustine Ramirez, MedSchoolCoach expert tutor, answers this medical school question: A 22-year-old man with beta-thalassemia presents to the emergency department with fatigue and dyspnea. Physical examination reveals pallor, but no jaundice or scleral icterus, and normal cardiopulmonary and abdominal examination. His extremities are warm and well perfused. Laboratory results reveal: hemoglobin 6.2, MCV 68, platelets 190,000, and leukocytes 7,500. One unit of packed red blood cells is transfused. Twenty minutes into the transfusion, the patient starts complaining of severe flank pain and chills. Temperature is 38.8 C, heart rate is 115/min, blood pressure is 105/70, and respiratory rate is 18/min. His urine is dark brown. Which of the following is the most likely mechanism for these findings?
  • Recipient anti-IgA antibodies against donor IgA
  • ABO incompatibility
  • Cytokine release from leukocytes
  • Recipient IgE against blood product component
  • Donor T-lymphocytes
  • Donor anti-leukocyte antibodies
Click to Reveal the Correct Answer

ABO incompatibility

Faustine Ramirez

Faustine graduated from the University of Washington in Seattle with a B.A. in Medical Anthropology and Global Health. She attends medical school at University of California, San Francisco where she designed and taught a course on clinical reasoning skills, developed curriculum materials for the pre-clinical pediatrics course, and led case-based sessions in pediatrics and infectious disease. She received a 253 on Step 1 and a 266 on Step 2 CK, and she scored in the 90th percentiles on all of her shelf exams.

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