When blood is required immediately for an emergency, its safety and availability will be dependent on whether pretransfusion compatibility testing has been completed and whether the antibody screen is negative.
The transfusion of uncrossmatched blood is a clinical decision determined by the level of urgency.
It is important for individuals who requested the transfusion to clearly state to the laboratory staff the degree of urgency for the provision of blood.
| Timeframes for the Availability of Blood in an Emergency Situation* | ||
| Time available | Pretransfusion compatibility testing completed | Pretransfusion compatibility testing not completed |
| Immediate | Immediate release of group specific blood |
Provision of Group O Rh(D)-negative red cells taken without pre-transfusion testing. It is essential to collect a blood sample for subsequent testing prior to the administration of uncrossmatched blood. |
| 10 minutes | Crossmatch compatible blood** | Provision of group-specific ABO and Rh(D) compatible red cells taken without compatibility testing. |
| 20 minutes | Crossmatch compatible blood** | Crossmatch compatible blood** |
| Note: *Dependent on laboratory logistics; **Should these emergency procedures detect the presence of a red cell antibody, considerable delays in the supply of compatible red cells may occur. | ||
Clinical judgement is required as to whether the immediate correction of blood loss or anaemia outweighs the risk of acute or delayed immune haemolysis. To avoid this dilemma, it is recommended that (where possible) patients be prospectively typed and screened when a need for blood transfusion may arise.
