Blood Group Incompatibility in Transfusion
Blood incompatibility in transfusion occurs when donor red blood cell (RBC) antigens mismatch recipient antibodies, most often involving the ABO blood group system. [1][2] Incompatibility can also involve RhD and other non-ABO “minor” RBC antigens, which can trigger acute or delayed hemolytic transfusion reactions. [1][3]
ABO Incompatibility Mechanisms
Acute hemolytic transfusion reactions most commonly result from ABO incompatibility. [2][1] ABO incompatibility is most often caused by clerical error, including patient misidentification, specimen mix-up, or incorrect blood component administration. [2][1]
Pre-Existing Recipient Antibodies
Incompatible transfusion occurs when the recipient has antibodies to donor RBC antigens. [3][1] Pre-existing antibodies typically arise from prior transfusion or pregnancy and can be directed against ABO or against non-ABO antigens. [3][5]
Non-ABO (Minor Antigen) Incompatibility
Non-ABO incompatibility results when recipient alloantibodies react with donor RBC antigens other than ABO. [1][3] Delayed hemolytic transfusion reactions are often caused by alloantibodies against non-ABO blood group antigens that were produced after prior sensitization. [1][3]
Delayed Hemolytic Transfusion Reaction Causes
Delayed hemolytic transfusion reactions can occur when previously formed antibodies become undetectable on routine pretransfusion testing but reappear after re-exposure to the corresponding antigen. [3][6] Delayed hemolysis can also reflect newly formed alloantibodies that develop after transfusion. [5]
Laboratory and Workflow Errors
Incompatible transfusion is frequently linked to failures in pretransfusion sample collection, labeling, or bedside matching with the intended blood product. [9][2] Crossmatch and antibody screen limitations can contribute when the relevant antibody is present at levels not detected at the time of testing. [3][13]
Other Sources of “Incompatibility” in Transfusion
Some serious transfusion reactions can mimic hemolytic incompatibility but are not caused by ABO or minor RBC antigen mismatch, including transfusion-related acute lung injury and transfusion-associated sepsis. [5] In nonimmune acute reactions, issues related to product handling and infusion practices can cause clinical deterioration without RBC antigen incompatibility. [18]
Clinical Contexts Increasing Alloimmunization
Alloimmunization against RBC antigens is promoted by prior transfusion exposure and can involve multiple antigen systems such as Rh and other minor blood group systems. [10][17]
Summary List of Common Causes
- ABO mismatch due to clerical error such as patient/sample mislabeling or wrong-unit administration. [2][1]
- Recipient antibodies against ABO antigens present before transfusion. [3][1]
- Recipient alloantibodies against non-ABO antigens (for example RhD and other minor blood group antigens). [1][10]
- Delayed hemolytic reaction due to previously sensitized alloantibodies with undetectable titers at the time of testing. [3][6]
- Delayed hemolytic reaction due to newly formed alloantibodies after transfusion. [5]
- Workflow and laboratory failures that reduce the sensitivity of compatibility testing or permit incorrect product assignment. [2][13]