Blood group

Blood group is a term used for any of the different types of human blood, the best know of them are those of the ABO system. The antigen characteristics of the human blood determines its compatibility in transfusion. There are also other blood group systems. In addition to this, blood types can be either negative or positive, depending on the absence or presence of the Rh factor’s D antigen. There are more than 30 different blood group systems related to different types of antigens.