Some more non-settled science, courtesy of The Ottawa Hospital:
A large Canadian study has shown a link between blood donor characteristics and transfusion recipients' outcomes. This is the first study to suggest that red blood cell transfusions from young donors and from female donors may be associated with poorer survival in recipients.
Guess the old simple classification system of sorting all blood into a couple of types was too simple. Just because blood doesn't cause an instant life threatening reaction doesn't mean it is totally compatible.
And like any good science article, the conclusion is "more research is needed!"
(Score: 4, Informative) by sjames on Wednesday July 13 2016, @08:25AM
That's exactly why donor blood is cross matched with the recipient except in emergency transfusions. The process can detect incompatibilities even of unknown types.