pretransfusion

Pretransfusion describes the set of clinical and laboratory activities conducted before administering a blood transfusion to a patient. The aim is to ensure compatibility between donor blood and recipient to minimize transfusion reactions and alloimmunization while ensuring adequate oxygen-carrying capacity.

Key components include ABO and Rh blood group typing of the recipient, and an antibody screen to detect unexpected red cell antibodies. If antibodies are identified, an antibody identification test determines specificity. A crossmatch compares donor red cells with recipient serum or plasma to confirm compatibility. Electronic crossmatching may be used when appropriate, particularly for patients with no clinically significant antibodies and up-to-date transfusion records.

Workflow involves confirming patient identity, obtaining an appropriate blood sample, and documenting indications for transfusion. The sample is tested in a licensed laboratory; results guide selection of compatible donor units, including antigen-negative units if antibodies are present. Neonatal and obstetric cases may require special considerations, such as differential testing or neonatal consults.

Donor unit testing includes infectious disease screening and compatibility testing. Risks such as transfusion reactions, alloimmunization, transfusion-related acute lung injury (TRALI), and transfusion-associated circulatory overload (TACO) are mitigated by pretransfusion testing and adherence to guidelines. In some settings, ABO/Rh typing and crossmatching may be electronically linked to electronic medical records to enable rapid, safe transfusion in emergencies.

Regulatory and professional guidelines from bodies like AABB and national authorities govern pretransfusion practice, with ongoing quality assurance, record keeping, and post-transfusion monitoring to ensure traceability and safety.