"ABO blood group is a system that reflects the presence or absence of antigens on the surface of erythrocytes and antibodies in the blood plasma." It is the most common system of blood groups in Pakistan.

 Erythrocytes carry signal molecules on their surface - antigens - agglutinogens. The two main antigens embedded in the erythrocyte molecule are A and B. Blood groups are found in the presence or absence of these antigens. The blood of people who have antigen A on red blood cells belongs to the second group - A (II), the blood of those on red blood cells - antigen B, belongs to the third group - B (III). If there are antigens A and antigens B on the red blood cells, the fourth group is AB (IV). It also happens that no one of these antigens is detected in the blood on red blood cells - then this is the first group - O (I).

 Typically, the body produces antibodies against those antigens (A or B) that are not present on red blood cells - these are agglutinins in the blood plasma. That is, in individuals with the second blood group - A (II) - antigens A are present on the red blood cells, and antibodies to the B antigens will be contained in the plasma - they are designated as anti-B (beta agglutinin). Since the antigens of the same name (agglutinogens) on the surface of erythrocytes and agglutinins in plasma (A and alpha, B and beta) react with one another and lead to the "gluing" of red blood cells, they cannot be contained in the blood of one person.

 The discovery of the ABO group system made it possible to understand why the blood transfusion was sometimes successful, and sometimes caused severe complications. The concept of compatibility of blood groups was formulated. For example, if a person with a second blood group - A (II), which contains antibodies to antigen B, transfer the third blood group - B (III), a reaction will occur between antigens and antibodies that lead to gluing and destruction of red blood cells and can have severe consequences up to a lethal outcome. Therefore, blood groups during transfusion must necessarily be compatible.

 The blood group is determined by the presence or absence of glutinous erythrocyte adhesions using sera containing standard antigens and antibodies.
In the blood transfusion centers on packets containing blood or its components obtained from donors, "O (I)", "A (II)", "B (III)" or "AB (IV)" are marked, which allows you to quickly find blood of the right group when it is required.

 What is the research used for?

 To find out what blood can be safely transfused to the patient. It is essential to make sure that the donor blood is compatible with the blood of the recipient - the person to whom it is going to be transfused. If the donor blood or its components have antibodies to the antigens contained on the red blood cells of the recipient, then a severe transfusion reaction can occur, caused by the destruction of red blood cells in the vascular bed.

 When is the study assigned?
Before the blood transfusion - both for those who need it and donors.
Transfusion of blood and its components is most often required in the following situations:
·        severe anemia,
·        bleeding that occurs during or after surgery,
·        severe injuries,
·        massive blood loss of any origin,
·        oncological diseases and side effects of chemotherapy,
·        disorders of blood clotting, in particular, hemophilia.
·        Before surgery.  
What do the results mean?
The results show the belonging of human blood to one of the four groups, depending on the presence of antigens on the red blood cells and antibodies present in the blood.

 Blood type |Antibodies
O (I)
α and β
An (II)
β
B (III)
α
AB (IV)
Antibody α and β will not.

 What can influence the result?
Hemolysis of serum can make the results unreliable.
It is also recommended.
Rhesus factor

 Who appoints the study?
Therapist, general practitioner, hematologist, transfusiologist, surgeon.