1. “The blood is the life…….Mr. Renfield” Dracula

2. Types
A blood type or blood group is a classification of blood based on the presence or the absence of inherited antigenic substances ( foreign substances ) found on the surfaces of the red blood cells. There are four main groups: A B AB O

3. Type A
Type A blood has an antigen A on the surface of the red blood cells, and therefore the immune system does not form antibodies against it.( Self-antigen)
Type A blood will recognize antigen B ( from B blood type) as foreign, an the immune system will attack and destroy these cells if introduced to the body ( through transfusion)

4. Type B blood
Are individuals that have type B antigens on their RBC surfaces.
As noted earlier, they will attack and destroy “A” antigens.

5. Type AB blood
This blood group has both antigen “A” and antigen “B” on their RBC surfaces. Since both are present, these individuals can accept blood transfusions from all groups ( Universal acceptor)

6. Rh blood group.
The Rh blood group is another classification for other antigens found on the RBC surfaces. This was wrongly named after the Rhesus monkey in which scientists thought that the same antigens were in that species.
Humans either have this antigen or not. Those that have the antigen present on their RBC surfaces are considered positive ( + ), while those that don’t are considered negative ( -).

7. Type O blood
This blood group has no antigens on the RBC surfaces. Since there are no antigens, O type individuals can give blood to all groups ( Universal donor), but cannot accept blood from any group except type O.