What is the most common cause of a transfusion reaction occurring 3 hours after an RBC transfusion?

• A. Febrile non-hemolytic reaction
• B. Acute hemolytic reaction
• C. Allergic reaction
• D. Transfusion-related acute lung injury (TRALI)

Answer: (A)

The most common cause of a transfusion reaction occurring 3 hours after an RBC transfusion is indeed febrile non-hemolytic reaction. This type of reaction is an immune response to white blood cells or cytokines that are released during the transfusion process. Symptoms typically include fever, chills, and malaise, and they can occur within hours after the transfusion has begun or shortly after it has ended.

This reaction is particularly common because it can happen even in patients who have had previous transfusions or pregnancies, leading to sensitization. The timing aligns well, as this type of reaction usually manifests a few hours post-transfusion.

In contrast, acute hemolytic reactions usually present much sooner, often within minutes, due to an ABO incompatibility and would not be the correct answer for a reaction occurring 3 hours post-transfusion. Allergic reactions can occur but are generally associated with symptoms such as hives or itching rather than a febrile response and may also present earlier. Transfusion-related acute lung injury (TRALI) typically manifests within 6 hours of transfusion and is characterized by acute respiratory distress, which again does not align with the 3-hour timeframe.

Hence, the febrile non-hemolytic