If your friend whith type o+ blood needs a blood transfusion, can your type a+ blood be given safely to him?

No: Only person with 0 neg can be a universal donor.

No: Absolutely not. With the o+ blood- you would have no antigen to a or b, however you will have anti a and anti b. In type a+, you will have a antigen. Thus, the a+ blood would be absolutely incompatible to o+.

See below: If patient is o+ and needs red blood cells, donors could be o+, o-. If patient needs plasma or platelets, any donor is fine.

See below: If patient is o+ and needs red blood cells, donors could be o+, o-. If patient needs plasma or platelets, any donor is fine.

Not really: People with type o blood usually develop antibodies to a and b over time. So the recipient with type o blood would destroy any transfused type a blood. Type o is the universal donor, not recipient. Neat question, thanks.