This is the name given to the classification of blood according to the characteristics that red blood cells present since they may lack or present antigens on their surface, there are a large number of blood groups but the most important are the groups belonging to the ABO system and Rh.
The ABO system was the first known blood group system, its name is derived from the four known groups of this system, which have an antigen that differentiates them from each other, these are group A, B, AB and O The latter differs from the others by lacking antigen. This system was discovered in 1901 by a scientist named Karl Landsteiner.
- Group A: the type A antigen is present on the surface of its blood cells and antibodies that act against B antigens are found in the plasma.
- Group B: These are similar to group A with type B antigen on the surface, AND antibodies that repel antigen A in plasma.
- Group o: it does not have antigens on the surface of its blood cells, but in its plasma it does have antibodies that act against type A and B.
- Group AB: has both types of antigens on the surface of blood cells, but lacks antibodies that act against antigens A and B.
The second system is Rh, also discovered by landsteiner in the 1940s, in a series of experiments carried out on Rhesus primates, where the new antigen (D) was discovered, this was called Rhesus factor, this was due to the primates where it was made. the discovery. Scientists classify people who have this factor as Rh positive and those who do not as Rh negative, which gives rise to eight blood groups.
- O negative: lacks antigens and Rh factor.
- Or positive: it does not present any type of antigens but if it presents the Rh factor, this group is one of the most common.
- A negative: only has A antigens.
- A positive: It has type A antigens and also the Rh factor, as well as positive O is one of the most common.
- B negative: has B antigens.
- B positive: contains Rh factor and B antigen.
- AB positive: contains antigens and lacks Rh factor.
- AB negative: it has both antigens (A and B) and the Rh factor.
