From the Guidelines
An ABO reaction is a severe, potentially life-threatening transfusion reaction that occurs when a patient receives blood containing incompatible ABO antigens, emphasizing the importance of positive patient identification and careful blood typing to minimize the risk of such reactions 1. To minimize the risk of ABO reactions, it is crucial to follow guidelines for patient identification and blood sampling, as outlined in the association of anaesthetists guidelines 1.
Key Considerations
- Positive patient identification is paramount prior to any blood transfusion episode to minimize wrong-blood-in-tube events and risks of ABO incompatibility 1.
- Blood samples must be collected and hand or electronically-labelled at the patient’s side by appropriately trained personnel 1.
- Patient monitoring is essential to identify and manage adverse reactions, with symptoms such as dyspnoea and tachypnoea being typical early signs of serious transfusion reactions 1.
Prevention and Management
- Prevention through careful blood typing, cross-matching, and verification procedures before transfusion is essential in clinical practice.
- Treatment involves immediately stopping the transfusion, maintaining blood pressure with IV fluids, supporting kidney function, and sometimes using medications to manage symptoms.
Risks and Complications
- Transfusion-associated circulatory overload (TACO) is now the most common cause of transfusion-related mortality and major morbidity, with risk factors including older age, comorbidities, and rapid transfusion 1.
- ABO reactions can cause symptoms including fever, chills, back pain, chest pain, nausea, vomiting, hypotension, and in severe cases, shock, renal failure, disseminated intravascular coagulation (DIC), and death.
From the Research
Definition of ABO Reaction
- An ABO reaction, also known as an ABO incompatibility reaction, occurs when there is a mismatch between the ABO blood group of the donor and the recipient, leading to an immune response 2.
- This reaction can cause hemolysis, which is the destruction of red blood cells, and can be severe enough to lead to disseminated intravascular coagulation, acute renal failure, shock, and even death 3.
Causes of ABO Reaction
- ABO incompatibility can occur due to errors in blood transfusion, hematopoietic and solid organ transplantation, hemolytic disease of the newborn, and intravenous immunoglobulin infusion 2.
- The reaction is caused by preformed immunoglobulin M (IgM) and IgG antibodies to ABO blood group antigens (isohemagglutinins) in the recipient's blood 2.
Symptoms and Outcomes of ABO Reaction
- Symptoms of an ABO reaction can include hypotension, hemoglobinuria, and hemoglobinemia, and can be severe enough to lead to death 4.
- The outcome of an ABO reaction depends on the volume of incompatible blood transfused, with larger volumes leading to more severe symptoms and a higher risk of death 4.
- Prompt recognition and discontinuation of the transfusion are critical in minimizing signs and symptoms and preventing death 4.
Treatment and Management of ABO Reaction
- Treatment of an ABO reaction is mostly supportive, but plasma exchange may be considered in severe cases 3.
- The decision to perform plasma exchange should be based on individual patient factors, such as the presence of cardiac and renal comorbidities, the volume of incompatible blood transfused, and the presence of hemoglobinuria 3.
- Immunohematological work-up is essential in ensuring transfusion management with utmost safety, and requires precise knowledge of the patient's clinical condition and treatment history 5.
Risks of Haemolysis due to ABO Incompatible Plasma Transfusions
- The risk of haemolysis due to ABO incompatible plasma transfusions is significant, with a reported mortality rate of 24% in one study 6.
- The lowest anti-A titre reported to cause haemolysis was 32, and the lowest reported volume associated with haemolysis was 100 ml in adults and 15 ml in children 6.