We know that there are different blood types in the population, which are called type A, B, O or AB and constitute the ABO system. Knowing the differences between these types is essential to ensure, for example, a blood donation that does not pose risks to a person's health. Let's understand why?
First of all we must remember that the blood It is formed by plasma, which constitutes the liquid part of the blood, and by the figured elements: erythrocytes, leukocytes and platelets. On the surface of erythrocytes there are substances called agglutinogens that determine each person's blood type. In plasma, in turn, we find antibodies called agglutinins, which are capable of reacting with the agglutinogens in erythrocytes.
Each blood type is characterized by the agglutinogen it has in its erythrocytes. Blood A, for example, has agglutinogen A; blood B has B agglutinogen, and blood AB has both types of antigens. Type O blood, on the other hand, has no agglutinogen.
In plasma, we observe different antibodies in each blood type. When we look at type A blood, we see in its plasma the Anti-B antibody. In blood B, the presence of Anti-A antibody is checked. Type AB blood, on the other hand, has no antibodies in the plasma, and blood O has Anti-A and Anti-B.
To better understand, see the table below:
Blood |
Agglutinogen in erythrocytes |
agglutinin in plasma |
THE |
THE |
Anti-B |
B |
B |
anti-A |
AB |
AB |
None |
O |
None |
Anti-A and Anti-B |
Imagine, for example, that you have type A blood and therefore Agglutinogen in your erythrocytes and Anti-B agglutinin in your plasma. If you receive blood from a type B person, the agglutinins will react with the erythrocytes in the blood you receive, causing them to be destroyed. Therefore, a person with type A blood cannot receive any blood from a donor that has B agglutinogen, as its antibodies will destroy that donor's red blood cells.
We can summarize it as follows:
-Patient with type A blood can receive blood from donor A or O.
-Patient with type B blood can receive blood from donor B or O.
-Patient with type AB blood can receive blood of any type as it does not have agglutinin in the plasma.
-Patient with type O blood can only receive blood from a type O donor, as it has Anti-A and Anti-B agglutinin.
The discovery of the ABO System revolutionized medicine, as it allowed the understanding of the incompatibility between some blood types.With this discovery, transfusions were safer and more lives were saved.
Take the opportunity to check out our video lesson on the subject:
