Is there a universal blood donor?
Published April 16, 2024 | 
( 1997 )
Is the universal blood donor type O negative or O positive?
In the past, a person with type O negative blood was considered to be a universal donor. It meant his or her blood could be given to anyone, regardless of blood type, without causing a transfusion reaction. This is no longer a relevant concept because of a better understanding of the complex issues of immune reactions related to incompatible donor blood cells.
Other than under extreme emergency conditions, donor blood is checked for compatibility with the recipient’s blood (cross-matched) before it is transfused, regardless of blood type. There are potentially important blood cell factors other than the A, B, AB and O blood groups and the Rh (Rhesus) factor that can lead to problems. Transfusion reactions can cause chills, fever, hives, wheezing and even shock and kidney failure, so every effort is made to prevent them. Although type O, Rh negative blood is less likely than other types to contain antigens that might cause a transfusion reaction, it is not free of all such risks.