Why type o is considered as universal donor?

Answer 1

All of our cells have protein "identifier" tags (proteins) on them that assist the function of the immune system. We start off with an immune system that can recognise almost every type of protein that can be made.

This is attenuated while we are developing in the womb because we do not want our immune systems to recognise and begin attacking self. So any immune cells that do recognise us while we are developing are destroyed. When we are born we have an immune system that can recognise pretty much everything but self.

There are 4 main blood groupings (but actually many more) - A, B, AB, and O. Blood cells of the A type have a the A protein on them. B's have B protein, AB have both, and O have neither.

So if you are have blood type A, your immune system will not recognise your blood cells, but will mount an attack on blood type B, or AB because they have the foreign, never encountered B protein on them (and vice versa).

O type blood does not elicit an immune response in anyone because the body's immune system does not recognise it as being foreign because it does not have foreign proteins on it, thus it is Universally accepted. People who are AB type are lucky as they can take anyones blood - their immune system will not respond to A proteins or B proteins and O +ve is called universal donor ,AB is called universal recepeint

Answer 2

Below is from the wikipedia:

Anti-A and Anti-B, the common IgM antibodies to the RBC surface antigens of the ABO blood group system are sometimes described as being "naturally occurring", however, this is a misnomer, because these antibodies are formed in infancy by sensitisation in the same way as other antibodies. The theory that explains how these antibodies are developed states that antigens similar to the A and B antigens occur in nature, including in food, plants and bacteria. After birth an infant gut becomes colonized with normal flora which express these A-like and B-like antigens, causing the immune system to make antibodies to those antigens that the red cells do not possess. So, people who are blood type A will have Anti-B, blood type B will have Anti-A, blood type O will have both Anti-A and Anti-B, and blood type AB will have neither. Because of these so called "naturally occurring" and expected antibodies, it is important to correctly determine a patient's blood type prior to transfusion of any blood component. These naturally occurring antibodies are of the IgM class, which have the capability of agglutinating (clumping) and damaging red cells within the blood vessels, possibly leading to death. It is not necessary to determine any other blood groups because almost all other red cell antibodies can only develop through active immunization, which can only occur through either previous blood transfusion or pregnancy. A test called the Antibody Screen is always performed on patients who may require red blood cell transfusion, and this test will detect most clinically significant red cell antibodies. The RhD antigen is also important in determining a person's blood type. The terms "positive" or "negative" refer to either the presence or absence of the RhD antigen irrespective of the presence or absence of the other antigens of the Rhesus system. Anti-RhD is not usually a naturally occurring antibody as the Anti-A and Anti-B antibodies are. Cross-matching for the RhD antigen is extremely important, because the RhD antigen is immunogenic, meaning that a person who is RhD negative is very likely to make Anti-RhD when exposed to the RhD antigen (perhaps through either transfusion or pregnancy). Once an individual is sensitised to RhD antigens their blood will contain RhD IgG antibodies which can bind to RhD positive RBCs and may cross the placenta.

* Blood group AB individuals have both A and B antigens on the surface of their RBCs, and their blood serum does not contain any antibodies against either A or B antigen. Therefore, an individual with type AB blood can receive blood from any group (with AB being preferable), but can donate blood only to another group AB individual. * Blood group A individuals have the A antigen on the surface of their RBCs, and blood serum containing IgM antibodies against the B antigen. Therefore, a group A individual can receive blood only from individuals of groups A or O (with A being preferable), and can donate blood to individuals with type A or AB. * Blood group B individuals have the B antigen on the surface of their RBCs, and blood serum containing IgM antibodies against the A antigen. Therefore, a group B individual can receive blood only from individuals of groups B or O (with B being preferable), and can donate blood to individuals with type B or AB. * Blood group O (or blood group zero in some countries) individuals do not have either A or B antigens on the surface of their RBCs, but their blood serum contains IgM anti-A antibodies and anti-B antibodies against the A and B blood group antigens. Therefore, a group O individual can receive blood only from a group O individual, but can donate blood to individuals of any ABO blood group (ie A, B, O or AB). If anyone needs a blood transfusion in a dire emergency, and if the time taken to process the recipient's blood would cause a detrimental delay, O Negative blood can be issued. Answer by wikipedia

Answer 3

A person with O blood type is known as a universal donor because anyone can receive this blood. A person with A, B, or AB blood can receive this because the antibodies would not be able to cause clumping of the blood cells, which would happen if someone with A blood would receive A or AB blood.

Answer 4

Type O blood can be given to all blood types.

In emergency situations, this is the blood type on stand by. There may not be enought time to Type and Screen someones blood to give them their specific type.

Answer 5

Because "O" type blood does not have any antigen and antibody coating on its surface.

Answer 6

O positive is the unversal blood donor

Answer 7

because it have no antigen.