In medical practice, there are often cases when patients lose a large amount of blood. For this reason, they need to transfuse it from another person - a donor. This process is also called transfusion. Before transfusion, a large number of tests are carried out. It is necessary to find the right donor so that their blood is compatible. With complications, violation of this rule often leads to death. At the moment, it is known that a universal donor is a person with the first blood group. But many doctors are of the opinion that this nuance is conditional. And there is no person in this world whose connective tissue of the liquid type is suitable for absolutely everyone.
What is a blood type
Blood group is called the totality of antigenic properties of human erythrocytes. A similar classification was introduced in the 20th century. At the same time, the concept of incompatibility appeared. Due to this, the number of people who successfully underwent a blood transfusion procedure has increased significantly. In practice, there are fourkind. Let's look at each one briefly.
First blood type
Zero or first blood type has no antigens. It contains alpha and beta antibodies. It does not have foreign elements, so people with blood type 0 (I) are called universal donors. It can be transfused to people with other blood types.
Second blood type
The second group has type A antigen and antibodies to agglutinogen B. It cannot be transfused to all patients. It is allowed to do this only for those patients who do not have antigen B, that is, patients with the first or second group.
Third blood group
The third group has antibodies to agglutinogen A and type B antigen. This blood can be transfused only to the owners of the first and third groups. That is, it is suitable for patients who do not have the A antigen.
Fourth blood group
The fourth group has both types of antigens, but does not include antibodies. The owners of this group can only transfer part of their blood to the owners of the same type. It has already been said above that a person with blood group 0 (I) is a universal donor. What about the recipient (the patient who takes it)? Those who have the fourth blood group can take any, that is, they are universal. This is because they do not have antibodies.
Features of transfusion
If antigens of that group that are incompatible get into the human body, then foreign erythrocytes will gradually stick together. This will breakcirculation. Oxygen in such a situation abruptly ceases to flow to the organs and all tissues. The blood in the body begins to clot. And if you do not start treatment on time, it will lead to quite serious consequences. That is why, before performing the procedure, it is necessary to conduct tests for the compatibility of all factors.
In addition to the blood type, the Rh factor must be taken into account before transfusion. What is it? It is a protein found in red blood cells. If a person has a positive indicator, then he has an antigen D in his body. In writing, this is indicated as follows: Rh +. Accordingly, Rh- is used to mark a negative Rh factor. As it is already clear, this means the absence of group D antigens in the human body.
The difference between blood type and Rh factor is that the latter only plays a role during transfusion and during pregnancy. Often a mother with the D antigen is not able to bear a child who does not have it, and vice versa.
The concept of universality
During the transfusion of red blood cells, universal donors are people with blood type one with a negative Rh. Patients with the fourth type and positive presence of antigen D are universal recipients.
Such statements are suitable only if a person needs to get the reaction of antigens A and B during the transfusion of blood cells. Often such patients are sensitive to foreign cells of a positive Rh. If a person has a systemHH is the Bombay phenotype, then this rule does not apply to it. Such people can receive blood from HH donors. This is due to the fact that in erythrocytes they have antibodies specifically against H.
Universal donors cannot be those who have antigens A, B or any other atypical elements. Their reactions tend to be taken into account infrequently. The reason is that during transfusion, a very small amount of plasma is sometimes transported, in which foreign particles are directly located.
In closing
In practice, most often a person receives a transfusion of blood of the same group and the same Rh factor that he has. The universal option is resorted to only when the risk is really justified. After all, even in this case, an unforeseen complication can occur, which will entail cardiac arrest. If the necessary blood is not available, and there is no way to wait, then doctors use the universal group.
