Understanding Which of the Following Would Cause a Major Transfusion Reaction?

September 26, 2025 •

3 min read

According to transfusion safety reports, clerical errors, such as misidentifying a patient, remain a leading cause of severe transfusion reactions, often leading to life-threatening outcomes. Answering the question, "Which of the following would cause a major transfusion reaction?" involves understanding these critical failures and their consequences.

Quick Summary

The most serious transfusion reactions are caused by ABO incompatibility, but other life-threatening issues include septic reactions from contaminated blood, transfusion-related acute lung injury (TRALI), and severe anaphylaxis.

Key Points

ABO Incompatibility: The most common cause of fatal transfusion reactions, resulting in an acute hemolytic reaction where the recipient's immune system destroys donor red blood cells.
Human Error: Clerical mistakes during patient identification or blood labeling are the primary triggers for ABO-incompatible transfusions.
TRALI: Transfusion-related acute lung injury can cause severe respiratory distress and is a leading cause of transfusion-related mortality.
Septic Reactions: The transfusion of blood products contaminated with bacteria, a particularly elevated risk with platelets, can lead to life-threatening septic shock.
Immediate Response: The immediate response to a suspected major transfusion reaction is to stop the transfusion, maintain the intravenous line with saline, and notify the medical team.

Introduction to Transfusion Reactions

Adverse events associated with blood transfusions can range from mild, manageable symptoms to severe, life-threatening conditions. A major transfusion reaction is a medical emergency requiring immediate intervention. Understanding the causes is crucial for prevention, rapid identification, and proper treatment.

The Culprits: Causes of Major Transfusion Reactions

Major transfusion reactions are categorized into several types, each with a distinct cause. The most feared is the acute hemolytic reaction, but other serious reactions, such as TRALI and septic shock, are also major concerns.

Acute Hemolytic Transfusion Reaction (AHTR)

This is one of the most severe and potentially fatal transfusion reactions, most often caused by a clerical error that results in ABO incompatibility. Receiving incompatible blood triggers an immune response where pre-existing antibodies attack donor red blood cells, leading to intravascular hemolysis. This can cause organ damage, kidney failure, and uncontrolled blood clotting. Common errors include mislabeled specimens or failure to identify the patient correctly.

Transfusion-Related Acute Lung Injury (TRALI)

TRALI is a serious, often fatal, complication characterized by acute respiratory distress. It involves donor antibodies reacting with recipient white blood cells, causing lung inflammation and pulmonary edema.

Transfusion-Associated Circulatory Overload (TACO)

This reaction occurs when blood products are infused too rapidly, overwhelming the patient's circulatory system. Patients with heart or kidney issues are particularly vulnerable. Symptoms include heart failure and fluid in the lungs.

Septic Transfusion Reaction

This life-threatening reaction is caused by bacterial contamination of blood products. It's a significant risk with platelets due to storage temperature. Symptoms include rapid fever, chills, and low blood pressure, potentially leading to septic shock.

Anaphylactic Transfusion Reaction

A rare but severe allergic reaction, often seen in individuals with IgA deficiency and anti-IgA antibodies. Exposure to IgA in donor blood triggers immediate, severe symptoms like respiratory distress, shock, and loss of consciousness.

Symptoms of a Major Transfusion Reaction

Prompt recognition of symptoms is vital. A sudden change during or after transfusion warrants investigation.

Fever and Chills: Possible indicators of AHTR or a septic reaction.
Shortness of Breath: A key sign of TRALI and TACO.
Pain: Chest, back, or IV site pain can occur, especially with AHTR.
Hypotension: A significant blood pressure drop in AHTR, septic reactions, and anaphylaxis.
Dark Urine: Characteristic of AHTR due to red blood cell destruction.
Anxiety: A feeling of impending doom is an early subjective symptom in AHTR.

Comparison of Major Transfusion Reactions


Reaction Type	Primary Cause	Typical Onset	Hallmark Symptoms
Acute Hemolytic (AHTR)	ABO incompatibility (clerical error)	Within 15 minutes	Fever, chills, back pain, dark urine
Transfusion-Related Acute Lung Injury (TRALI)	Donor antibodies against recipient's white blood cells	Within 6 hours	Acute respiratory distress, hypoxemia
Transfusion-Associated Circulatory Overload (TACO)	Too-rapid fluid administration	Within 1–12 hours	Dyspnea, crackles in lungs, hypertension
Septic Reaction	Bacterial contamination	Within 2 hours	High fever, severe chills, hypotension
Anaphylactic Reaction	Recipient IgA deficiency, anti-IgA antibodies	Within 5–15 minutes	Sudden respiratory distress, shock, hives

Management and Prevention

Immediate action for a suspected reaction is stopping the transfusion. Supportive care follows, tailored to the specific reaction. Prevention is key, with strict protocols in place.

Preventative measures include:

Rigorous Patient Identification: Crucial for preventing ABO-incompatible transfusions.
Leukoreduction: Reduces risk of febrile non-hemolytic reactions and potentially TRALI.
Irradiated Blood Products: Prevents GVHD in immunocompromised patients.
Careful Administration: Adjusting infusion rates for at-risk patients minimizes TACO risk.

For more detailed information, the Merck Manuals offer a valuable resource: https://www.merckmanuals.com/home/blood-disorders/blood-transfusion/precautions-and-adverse-reactions-during-blood-transfusion.

Conclusion

Understanding potential adverse reactions, particularly ABO incompatibility as a leading cause of fatal hemolytic reactions, is essential for transfusion safety. TRALI, TACO, and septic reactions are also significant concerns. Healthcare providers follow stringent protocols for prevention, and prompt recognition and management are critical for patient outcomes.

Frequently Asked Questions

The most common cause of a fatal transfusion reaction is an acute hemolytic reaction resulting from ABO incompatibility. This typically occurs due to human or clerical error, such as a patient receiving the wrong blood type.

During an acute hemolytic reaction, the recipient's antibodies attack and destroy the incompatible donor red blood cells. This leads to the release of hemoglobin, which can cause kidney damage, widespread clotting, and potentially fatal shock.

Transfusion-related acute lung injury (TRALI) is caused by donor antibodies that activate an inflammatory response in the recipient's lungs. This results in fluid accumulation and acute respiratory distress, a life-threatening condition.

Yes, bacterial contamination of blood products can lead to a severe septic transfusion reaction. This is a life-threatening condition that can result in septic shock and is a serious risk, especially with platelets stored at room temperature.

Initial signs of a severe reaction can include fever, chills, back or chest pain, and a feeling of impending doom. More severe symptoms, such as difficulty breathing, low blood pressure, or dark urine, may follow rapidly.

If a major reaction is suspected, the transfusion should be stopped immediately. The IV line should be kept open with saline, and medical staff should be notified for an emergency evaluation and response.

Major transfusion reactions are prevented through strict patient identification protocols, thorough cross-matching, proper handling of blood products, and using specialized products like leukoreduced or irradiated blood for high-risk patients.