Physically, when we see blood, it is red, and we think that we all have the same type of blood. But actually the blood is not same in all individuals. Everyone's blood has a different chemical composition, and we also hear about different types such as blood group A, B, AB, O, positive, negative etc. What actually are these types, and why everyone has a different blood group. Here we have discussed the details about these two.
A.B.O blood group system
There are four types of blood group in A.B.O blood group System; A, B, AB and O blood group, and this difference is due to the presence of an antigen on the surface of R.B.C.
Antigens are substances which triggered the formation of antibodies in the body. Antibodies are responsible to activate the immune system, which is the defense system of our body against diseases.
There are two types of antigens, one is external which comes from outside into the body and activate the immune system, and one is internal which is made by the body itself. So the antigens present on RBC are internal.
A blood group
A person with A blood group has a substance on the surface of the RBC called N- acetyl glucosamine. This substance is called A antigen, which separate this blood type from others. Anyone who has this antigen on the RBC surface has A blood group, and the antibody present in the plasma for A blood group is Antibody B.
B blood group
The B blood group individuals have a substance on their RBC called galactose. This substance is called B antigen. This molecule is produced within the RBC and is transfer to the surface of RBC by an enzyme. Anyone who has B antigen on the RBC surface has B blood group. The antibody present for antigen B is antibody A.
AB blood group
In case of AB blood group, the individual has both antigens A and B on the surface of the RBC, and there is no antibody in AB blood group. Because both antigens are present; So A antibody would react with A antigen and B antibody would react with B antigen.
O blood group
In case of O blood group, there is no antigen on the surface of RBC, but both antibodies A and B are present. O blood group is special, and it is also called universal donor because it can give blood to anyone.
Rh factor
The Rh is another substance which is also present on the surface of RBC, but not in all individuals. Anyone who has Rh factor in the blood, then his blood type will be +ve and the one who doesn't possess the Rh factor has a negative blood type. For example, a person with A blood group if possess Rh factor then this blood type will be (A+) and if there is no Rh factor, then that will be (A-) blood group.
Blood group test
During the test of the blood group, the sample of blood is mixed with an antibody. For example, If the antibody is A and the blood group is A, then the blood sample will stick with antibody because A antigen react with A antibody. This show that your blood type is A. The B blood type is also tested like this. Like wise, if the blood sample doesn't stick with antibody, then the blood group is O because the O blood group doesn't have any antigens.
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