Signs of human blood, both immune and genetic, by the similarity of substances (antibodies) foreign to the body can be combined into a certain type called a blood group. Any person belongs to a certain type of blood that forms at an early stage of the life of the embryo. Molecules that belong to a particular blood group are called antigens. When it enters an organism alien in antigenic composition, they cause the formation of antibodies, which can combine into conglomerates.
Blood: what happens and how is it different from the other?
Blood transfusion, as an indispensable procedure in medicine, underwent some changes in the 20th century. Scientists have proven that transfusion can occur far from every person. Then the question arises, which blood type is suitable for everyone, without exception, and is there such a one? Individual characteristics and belonging to different types led to the fact that when mixed with an alien to the native body coagulated.
There are 4 types:
- The first, in which there are no antigens
- The second contains antigen A
- The third contains antigen B
- The fourth has antigens A, B together
I wonder which blood type is suitable for all people? When mixing donor blood and a recipient belonging to one group, new blood cells circulate among “their own” in the normal way. Conversely, incompatibility can be dangerous to human health. Consider the compatibility table:
| Blood type number | For donors | For recipients |
| 1 | All types | First |
| 2 | Second, fourth | First two |
| 3 | Third, fourth | First, third |
| 4 | Fourth | All types |
The table clearly shows which blood type is suitable for all others. It turns out that number 1 can be combined with others and it can be transfused with people of all types. Therefore, blood I is very valuable, does not harm the lives of other people in case of transfusion, and its owner is a universal donor.
The last type (4) is peculiar. It appeared by mixing Indians and Europeans, that is, carriers of groups 1 and 3. It contains antigens A and B, but no antibodies. That is,
blood group 4, compatibility as a donor is possible only with the fourth group, and compatibility as a recipient is possible with people of all existing types.
Rhesus factor
How it manifests itself at the gene level:
- parents have Rhesus positive - a child can have a Rhesus factor either (+) or not (-);
- one of the parents has a positive Rhesus factor, the other has a negative Rhesus, the child can have both positive and negative;
- in the father and mother, the Rh factor is negative, the child will have only negative.
To do the transfusion, it is necessary to establish compatibility by blood group and rhesus without fail. When positive Rhesus is mixed with negative, anti-Rhesus antibodies appear in the blood and are produced by the donor’s body and remain in it.
In Europe, there are about 15% of the total Rh negative population. Such people can have a blood transfusion that is compatible with them in the group and in the Rh factor (meaning negative).
It is worth remembering which blood type is suitable for all people and what donors and recipients need to know before blood transfusion.