Types of Transfusion Reactions
Transfusion reactions are classified into acute reactions (occurring within 24 hours) and delayed reactions (developing 48 hours or more after transfusion), with the most clinically significant acute reactions being TRALI, TACO, and hemolytic reactions—the top three causes of transfusion-related mortality. 1, 2, 3
Acute Transfusion Reactions (Within 24 Hours)
Life-Threatening Reactions
Transfusion-Related Acute Lung Injury (TRALI)
- Leading cause of transfusion-related mortality 1, 2
- Occurs at a rate of 8.1 per 100,000 transfused blood components 1
- Presents with respiratory symptoms within 1-6 hours of transfusion 4
- Associated particularly with FFP transfusion 1
Transfusion-Associated Circulatory Overload (TACO)
- Second leading cause of transfusion-related death 2
- Incidence ranges from <1% to 8% of transfusions 1
- Mortality rate of 5-15% in affected patients 1
- Particularly common with plasma transfusion due to large volumes and increased infusion rates 1
Acute Hemolytic Transfusion Reactions (AHTR)
- Third leading cause of transfusion-related mortality 2
- Fatal hemolysis occurs at approximately 8 per 10 million RBC units transfused 1
- Commonly due to human error and failure to apply rigorous cross-checks 5
- Presents with hypotension, tachycardia, hemoglobinuria, and microvascular bleeding 1, 4
- General anesthesia may mask symptoms 1
Bacterial Contamination/Septic Transfusion Reaction
- Leading cause of death from platelet transfusions 4
- Fever within 6 hours after platelet transfusion is particularly concerning 4
- Presents with fever, hypotension, and hemodynamic instability 4
Non-Life-Threatening Acute Reactions
Febrile Non-Hemolytic Transfusion Reactions (FNHTR)
- Most common type of transfusion reaction 6, 3
- Incidence of 1.1% with prestorage leukoreduction and 2.15% with poststorage leukoreduction 1
- Presents with fever, chills in awake patients 1
- May be masked during general anesthesia 1
Allergic Reactions
- Occur at rates of 1:591 to 1:2,184 plasma units transfused 1
- Range from mild urticaria to severe anaphylaxis 1, 6
- Anaphylactic reactions occur at 1:18,000 to 1:172,000 transfusions 1
- Most frequently occurring reaction type despite being rarely life-threatening 6
Transfusion-Associated Hypothermia (TAH)
- Common in massive transfusion settings, particularly trauma patients 5
- Preventable with patient warming strategies 5
Delayed Transfusion Reactions (≥48 Hours)
Delayed Hemolytic Transfusion Reactions
Post-Transfusion Purpura
Transfusion-Related Immunomodulation
- Long-term immunologic effect of transfusion 3
- May affect patient outcomes beyond immediate transfusion period 3
Transfusion-Associated Graft-Versus-Host Disease
- Rare but serious delayed complication 6, 3
- Preventable with irradiated blood products in high-risk patients 3
Iron Overload
- Occurs with long-term, repeated transfusions 3
- Requires monitoring and chelation therapy in chronically transfused patients 3
Infectious Complications
- HIV: 6.8 per 10 million transfused components 1
- HCV: 8.7 per 10 million transfused components 1
- HBV: 28-36 per 10 million transfused components 1
- Other infections include malaria, Chagas disease, West Nile virus, and variant Creutzfeldt-Jakob disease 1
Post-Transfusion Mononucleosis Syndrome
Critical Clinical Pearls
Life-threatening transfusion reactions require major medical intervention (vasopressors, intubation, or ICU transfer) and occur at a rate of 7.1 per million transfusions 1
The most common pitfall is continuing transfusion despite isolated fever, as general anesthesia and critical illness can mask early signs of serious reactions 4
When any transfusion reaction is suspected, immediately stop the transfusion, maintain IV access, and notify the blood bank before determining the specific reaction type 4, 8