IIRC blood type AB is the universal recipient
That's how it's commonly described, but it's a misnomer. First, because there are rare blood types which have antigens other than A and B; and second, because whole blood from someone with a different type will generally contain antibodies for the A or B antigen, or both, which will bind to the recipient's own red cells. So while "universal recipients" can receive some blood from donors of other common types, it's not a good idea to pump them full of mismatching blood.
Of course, hospitals should, and in my very limited experience do, check the recipient's type before topping him or her off, and don't just rely on medical records.
Biting the hand that feeds IT
