Anemias USMLE Step 1 Practice Question
A 54-year-old man with a history of peptic ulcer disease receives a packed red blood cell transfusion following acute gastrointestinal bleeding. Within minutes, he develops fever (39.2°C), flank pain, hypotension (BP 88/52), tachycardia (HR 118), and dark urine. Laboratory studies reveal elevated serum creatinine (2.8 mg/dL) and decreased haptoglobin. He denies prior transfusions. Which of the following best explains the most likely mechanism of his reaction?
Answer choices
- ARecipient anti platelet antibodies causing thrombocytopenia
- BPreformed recipient antibodies against donor ABO antigens causing complement mediated intravascular hemolysisCorrect answer
- CVolume overload due to rapid transfusion
- DIgE mediated mast cell degranulation due to donor plasma proteins
- ET cell mediated graft versus host disease
- FFebrile nonhemolytic transfusion reaction
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