Blood types

When transfusing, it is necessary to first determine the blood group and donor and patient.

There are 4 blood groups.

ABO System

At the end of XIX century. The Australian scientist Karl Landsteiner, while conducting the study of erythrocytes, discovered a curious pattern: in some red blood cells (red blood cells) of some people there may be a special marker, which the scientist designated with the letter A, in others - marker B, the third did not show either A or B. Later it was found out that the markers described by Landsteiner are special proteins that determine the specific specificity of cells, or antigens. In fact, these studies divided the whole of humanity into 3 blood groups

The fourth group was described in 1902 by the scientists of DeCastello and Sturley. The joint discovery of scientists was called the ABO system.

Rhesus factor

Unlike blood group antigens, Rh factor is an antigen found only in the erythrocyte membrane and not dependent on other blood factors. Rhesus factor is transmitted by inheritance and persists throughout the life of a person. 85% of people in which the Rhesus factor is in red blood cells have Rh-positive blood (Rh +), the blood of the rest of people does not contain the Rh factor and is called Rh-negative (Rh-).

Kell factor

The Kell system is a blood group system that includes 25 antigens, including the most immunogenic after A, B and D, the K antigen.

Based on the presence of antigen K in erythrocytes or its absence, all people can be divided into two groups: Kell-negative and Kell-positive. The presence of K antigen (Kell-positive) is not pathology and is inherited, as are other human group antigens. In Russia, it occurs in 7-10% of the population.

At present, the presence of K antigen is determined in blood service establishments as the most dangerous for the emergence of immunological complications. Many cases of hemotransfusion complications and hemolytic disease of newborns, the cause of which was isoimmunization with antigen K.

Kell-negative should only be transfused blood from donors who do not have antigen K to prevent hemolysis. Persons Kell-positive are universal recipients of blood, as they do not have rejection of its components.

In order to prevent post-transfusion complications due to the K antigen K, the blood transfusion units and stations are given an erythrocyte suspension or mass that does not contain this factor for transfusion into medical institutions. When transfusing all types of plasma, platelet concentrate, leukocyte concentrate, the antigen K of the Kell system is not taken into account.

Therefore, Kell-positive donors recommend plasma donation.