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.
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 situation*
Red cells provided O RhD negative Pretransfusion compatibility testing completed None. A blood sample should be collected before uncrossmatched blood is administered.
- 10 minutes
Red cells provided Group specific, uncrossmatched Pretransfusion compatibility testing completed Yes - limited. ABO & RhD typing
- 30-40 minutes
Red cells provided Crossmatch compatible** Pretransfusion compatibility testing completed Yes - completed. ABO & RhD typing, antibody screen
*Dependent on laboratory workflow;
**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 & RhD compatible but otherwise serologically incompatible red cells until further investigations are completed.