In the past AB plasma was used for this purpose because it lacks anti-A, anti-B and anti-A,B antibodies. Concerns about the use of type A plasma is the presence of anti-B.
Problems with AB plasma:
(1) in short supply because donors represent 1 to 5% of populations (4% in Whites and Blacks).
(2) associated with higher risk of TRALI (because donors are not restricted in the same way as other blood types)
Group A plasma is more readily available (27% Blacks, 40% Whites).
Protocols for emergency transfusion is to give group A plasma initially but not in an unrestricted fashion. Use might be restricted to the first few units or for a limited time period (up to 24 hours). It is important to limit the volume of incompatible plasma transfused.
The use of type AB plasma for emergency transfusion was significantly reduced.
In the various studies where this practice has been trialed:
(1) Type A plasma was received by some type B and type AB patients.
(2) No hemolytic reactions were reported.
(3) No difference in outcome was seen between those receiving incompatible plasma and those receiving compatible plasma.
One issue is the length of follow-up. The patient would be at risk for delayed transfusion reaction. However, if the patient is bleeding then coated erythrocytes would be lost so a significant transfusion reaction might become unlikely.
Another issue is the number of patients treated. As the number of patients increase then low frequency adverse events may be noted.
