Which blood groups are transfusion compatible?

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Offline thedoc

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Which blood groups are transfusion compatible?
« on: 18/01/2014 11:30:01 »
Jo Joseph asked the Naked Scientists:
Why do people have different blood groups? Why can some groups not be mixed?

Thanx for a great show

What do you think?
« Last Edit: 18/01/2014 11:30:01 by _system »


Offline CliffordK

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Re: Which blood groups are transfusion compatible?
« Reply #1 on: 18/01/2014 23:56:15 »
Your blood can express antigens of 3 basic classes:
A (or nothing)
B (or nothing)
Rh+ (or nothing)
O is the abbreviation for neither A nor B.

If a "foreign" antigen is injected into a person, they can mount an immune response against it which can be very harmful when injecting foreign blood.

So, a person with A+ blood can receive either identical A+ blood, or one of (A-, O+, or O-) as they  don't express antigens that the body isn't used to.

An AB+ recipient has all the antigens and is known as a universal recipient, allowing them to receive any type of blood.

An O- recipient has none of the blood type antigens and can ONLY be given O- blood.  However, they are known as the universal donor as they don't have any of the major blood antigens.

Why do we have blood types?
It is part of the same antigen recognition system for our immune system that recognizes bacteria and other foreign invaders in the body.  Perhaps one should find it amazing that humans only have 3 major blood types.  Any other transplant is far more complex.

There are some theories that various diseases may have helped select for different blood antigens.

Given time, however, one should do a full compatibility check of the blood in case some minor antigen also creates a reaction.