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The most important blood groups in transfusion are the ABO blood group system and the RhD blood group system. Blood groups are determined by a protein (antigen) on the surface of the red cell. So, the ABO system has A and B antigens and the RhD system has the D antigen.

In all, there are 30 major blood group systems. This means a person may be A RhD positive, and at the same time Kell (Kell system) positive, M and N (MNS system) positive and Lea and Leb (Lewis system) positive.

The ABO Blood Group System:

If you have blood group A then you have got the A antigen on your red cells. Blood group B means you have the B antigen, while group O has neither, and group AB has both A and B antigens. The ABO system has associated anti-A and anti-B antibodies, antibodies being the body’s natural defence against foreign antigens.

These antibodies are found in the plasma. Blood group A has the A antigen. This group recognises the B antigen as foreign and can make anti-B antibodies. Similarly, blood group B has the B antigen and therefore recognises the A antigen as foreign and can make anti-A antibodies.

Group AB has both the A antigen and the B antigen so this group makes no antibodies. Group O has neither A nor B antigen so this group can be given safely to any other group. This is why Group O donors are known as ‘universal donors’. Group O can make both anti-A and anti-B antibodies if exposed to these antigens.

Giving someone blood from the wrong ABO group could be life-threatening. For instance, the anti-A antibodies in group B attack group A cells and vice versa. This is why group A blood must never be given to a group B person.

The RhD System

Another important blood group system in transfusion is the RhD system. 85% of people have the D antigen on their red blood cells and are RhD positive. The remaining 15% lack the D antigen and are RhD negative. Your blood group is defined by your ABO group together with your RhD group. For instance, someone who is group A and RhD negative is known as A negative.

Prestige Diagnostics offers a range of high quality Blood Grouping Reagent products to meet the needs of our distributors, blood banks, clinics, hospital laboratories and transfusion centres across the world.

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