is A positive blood a universal donor type?

O negative is the universal donor because when O+ve blood group is transfused to -ve blood group recipient, antibodies are produced which causes hemolysis of Rh +ve labelled blood cells. When O-ve blood is transfused to Rh +ve recipient, no antibodies are produced as donor blood has no Rh factor present on blood cells, so no transfusion reaction occurs. Thus, O -ve is universal donor.