Transfusion Reactions

A 58-year-old man with chronic kidney disease and hemoglobin of 7.2 g/dL receives 2 units of packed red blood cells for symptomatic anemia. Twenty minutes into the transfusion, he develops fever (39.2°C), rigors, and mild dyspnea. His blood pressure remains stable at 128/82 mmHg. Urinalysis shows no hemoglobinuria. Direct antiglobulin test (DAT) is negative. What is the most likely diagnosis?

A 42-year-old woman with thalassemia major undergoing chronic transfusion therapy receives her 45th unit of packed red blood cells. Within 5 minutes of starting the transfusion, she develops severe back pain, chest tightness, and dark urine. Her blood pressure drops from 118/76 to 92/54 mmHg. Temperature is 38.8°C. Hemoglobin drops from 8.5 to 7.2 g/dL within 1 hour. Serum creatinine rises from 0.9 to 1.8 mg/dL. What is the most appropriate immediate management?

A 58-year-old man with chronic kidney disease (hemoglobin 7.2 g/dL) receives 2 units of packed red blood cells for symptomatic anemia. Within 15 minutes of transfusion initiation, he develops fever (38.5°C), rigors, and back pain. Vital signs show BP 110/70 mmHg, HR 110/min, RR 22/min. Urine output drops to 0.3 mL/kg/hr and becomes dark brown. Serum creatinine rises from 2.8 to 3.4 mg/dL within 2 hours. Direct antiglobulin test (DAT/Coombs) is positive. What is the most likely diagnosis?

A 42-year-old woman with thalassemia major receives her 50th transfusion of packed red blood cells. Two hours after transfusion begins, she develops fever (38.2°C), mild dyspnea, and a dry cough. Examination reveals bilateral fine crackles at the lung bases and oxygen saturation of 88% on room air. Chest X-ray shows bilateral pulmonary infiltrates without cardiomegaly. Echocardiography is normal. Direct antiglobulin test (DAT) is negative. What is the most likely diagnosis?

Which of the following is the most common cause of acute hemolytic transfusion reaction?