For some diseases or blood loss, a person is given a blood transfusion.
Blood for transfusion is taken from healthy adults – donors, special chemicals are added to it (so that the blood does not clot and is suitable for a long time) and is sealed in special glass vessels. This canned blood can be transported over long distances.
In 1900, the Austrian scientist Karl Landsteiner discovered blood groups, for which he received the Nobel Prize in 1930.
To designate blood groups, use the Roman numerals I – IV, or the Latin letters A, B and zero – the AB0 system.
There are 4 main blood groups: I, or zero – I (0), II (A), III (B) and IV (AB). The possession of a particular blood group is genetically determined.
Blood groups differ in the content of specific proteins in blood plasma and erythrocytes, which are not always compatible – plasma proteins can glue erythrocytes together, destroy them (the rules for blood transfusion are associated with this).
more than 40% of Europeans have II (A) blood group, 40% – I (0), 10% – III (B) and only 6% – IV (AB).
Each blood group accepts the blood of the same group and the I (0) group.
In the blood plasma of group IV (AB) there is no protein that sticks together red blood cells, so people with this group are allowed to transfuse blood of any other group. These people are called universal recipients.
Blood of the I (0) group can be transfused to any person, since there is no protein in its erythrocytes, which can be influenced by the proteins of the recipient’s plasma and cause their destruction. People with I (0) blood group are called universal donors.
Currently, it is customary to transfuse only the blood group of the same name.
Another characteristic of blood groups is the Rh factor. People who have it in their blood are called Rh-positive Rh (+), and those who do not have it are called Rh-negative Rh (-).
The Rh factor is especially important to take into account during organ and tissue transplants and during pregnancy. If an Rh (-) Rh (-) Rh-negative mother develops a Rh (+) Rh (+) fetus (inherited a Rh-positive factor from the father), then substances that destroy the fetal red blood cells will be formed in the mother’s blood, and it may die.