Blood transfusions are generally safe but can carry considerable risks. This review summarizes the different types of transfusion reactions and ways to diagnose and manage them. Symptoms are often overlapping and nonspecific. When a reaction is suspected, it is critical to stop the transfusion immediately and report the reaction to the blood bank, as this can affect the patient’s outcome. New evidence-based algorithms of transfusion, newer blood screening methods and donor policies and deferrals, new laboratory testing, electronic verification systems, and improved hemovigilance lead to the avoidance of unnecessary transfusions and decrease the incidence of serious transfusion reactions.
Acute reactions occur within 24 hours of transfusion and include acute hemolytic transfusion reactions, febrile nonhemolytic transfusion reactions, allergic transfusion reactions, and transfusion-related acute lung injury.
Delayed reactions occur after 24 hours, usually days to weeks after the transfusion, and include delayed hemolytic transfusion reactions, transfusion-associated graft-versus-host disease, and posttransfusion purpura.
New evidence-based algorithms of transfusion, newer blood screening methods and donor policies and deferrals, new laboratory testing, electronic verification systems, and improved hemovigilance lead to the avoidance of unnecessary transfusions and decrease the incidence of serious transfusion reactions.
Transfusion reactions are defined as adverse events associated with the transfusion of blood products ( Table 1 ). Nearly 21 million blood components are transfused each year in the United States. In fact, blood transfusions are the most common therapeutic procedure among hospitalized patients. Although transfusion of blood and its products is a common medical practice, it is not without complications. Transfusion reactions may be seen in up to 1% of all transfusions. Reactions range in severity from mild to life-threatening and can sometimes be fatal. Further, accurate diagnosis can be problematic, as reactions often present with nonspecific and/or overlapping symptoms ( Fig. 1 ); however, despite this complexity, using a symptom-based approach is an effective means to determine the type of transfusion reaction. The most frequent symptoms include fever, chills, urticaria (hives), and pruritus (itching), which usually resolve without specific treatment after stopping the transfusion. Other symptoms, such as respiratory distress, high fever, hypotension, and hemoglobinuria can be the first indicators of a more severe reaction.