What defines a febrile nonhemolytic transfusion reaction?

A febrile nonhemolytic transfusion reaction is primarily characterized by a rise in temperature of 1°C or higher following a transfusion. This type of reaction is generally considered a common and often benign response to the transfusion of blood products, particularly due to the recipient's immune response to the white blood cells or cytokines in the transfused blood.

The elevation in body temperature typically occurs within a few hours of the transfusion, usually after the first few units of blood are given, indicating that the body is reacting to the transfused material. The definition focuses on the temperature increase as the key clinical sign of this reaction, thereby allowing healthcare providers to recognize it and manage it promptly.

While there are other types of transfusion reactions that may occur, such as hemolytic reactions, delayed immunologic responses, or severe allergic reactions, those are distinct from febrile nonhemolytic reactions and involve different symptoms and mechanisms. This clarification of what specifically constitutes a febrile nonhemolytic transfusion reaction is crucial for understanding how to monitor and respond to patients during transfusion therapy.