When blood is required in an emergency, how quickly it can be provided and degree of compatibility will depend on whether pretransfusion testing has been completed, and whether the recipient's antibody screen is negative.
In extreme or life-threatening situations where pretransfusion testing isn’t possible or can’t be completed in time, it may be necessary to transfuse uncrossmatched blood. See the National statement for the emergency use of group O red cells.
This is a clinical decision determined by the level of urgency and whether the immediate correction of blood loss or anaemia outweighs the potential risk of acute or delayed immune haemolysis due to potentially incompatible blood.
It’s important that a specimen is collected for subsequent pretransfusion testing before blood products are administered.
In emergency situations, it is important for individuals requesting a transfusion to clearly inform the laboratory staff of the urgency of transfusion.
Typical timeframes for the provision of blood in an emergency*
Red cells provided O RhD negative** Pretransfusion compatibility testing completed None. A blood sample should be collected as soon as possible and before blood products are administered.
- 10 minutes
Red cells provided Group specific, uncrossmatched Pretransfusion compatibility testing completed Yes - limited. Blood group (ABO/RhD type).
- 30-40 minutes
Red cells provided Crossmatch compatible*** Pretransfusion compatibility testing completed Yes - completed. Blood group (ABO/RhD type) and antibody screen.
*Dependent on laboratory workflow;
**For females of childbearing potential (≤ 50 years) and paediatric males (≤ 18 years; or as per local paediatric policy) - issue group O RhD negative uncrossmatched red cells until the patient’s blood group (ABO/RhD type) has been determined using a valid current specimen.
For females > 50 years and all adult males > 18 years - issue group O RhD positive uncrossmatched red cells until the patient’s blood group (ABO/RhD type) has been determined using a valid current specimen.
***If a red cell antibody is detected there may be a delay while the antibody is identified, and compatible red cells found. It may be necessary to provide ABO and RhD compatible but otherwise serologically incompatible red cells until further investigations are completed.