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Human Anatomy, Physiology, and Medicine. Anything human!
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Blood agglutination

Mon Mar 06, 2006 7:43 am

Hey friends i have a doubt on the agglutination of blood during transfusion.

Suppose blood type O is given to a person whose blood group is A.
Blood type O has two type of antibodies "anti-a" and "anti-b"
Blood type A has antigen A and antibody "anti-b"
We know that anti-b of blood type A will not react with blood type O as it does not have any antigen.

But my doubt is Will the antibody "anti-a" of type O blood will react with the antigen A of type A blood ?

Please give reason :roll:

Mon Mar 06, 2006 9:44 am

First, you must understand the concept, which is "antigen:antibody reaction", like this:
- antigen A + anti-a = agglutination
- antigen B + anti-b = agglutination

Anti-b of blood A will not react with blood O because blood O does not contain antigen B.
- anti-b + anti-a = no agglutination
- anti-b + anti-b = no agglutination
- anti-a + anti-a = no agglutination

Anti-a of blood O will react with blood A because blood A contains antigen A.

Tue Mar 07, 2006 6:38 am

Anti-a of blood O will react with blood A because blood A contains antigen A.


sooo why do we give blood O to a person whose blood group A? it will cause agglutination.right?

Tue Mar 07, 2006 8:02 am

Dr.Stein wrote:
Anti-a of blood O will react with blood A because blood A contains antigen A.


Dear Sir,
If it is true then why blood O is called universal donor and it can be given to any person?

Tue Mar 07, 2006 8:07 am

Similarly blood AB contains no antibody but has both antigen A & B.

If blood A is given to the person whose blood is type AB then the "anti-b" of blood A will react with the antigen B of the blood AB and cause agglutination. Is it correct?

Then Why blood AB is called universal recepient?


Please clear my doubts.

Tue Mar 07, 2006 12:51 pm

Group O: No antigen on the blood cell, no agglutination because neither antiA nor antiB react with it. So it can be given to anyone (provided Rh groups and minor groups are not a problem)

Group AB: The carrier have neither antiA nor antiB (that woud cause agglutination in their blood) so whatever blood is given it won't agglutinate. Provided the same caveat as above is true.

Tue Mar 07, 2006 7:08 pm

what they are asking patrick, and what i still have not figured out is:
If you give O blood to a person who has A blood type, why don't the antiA antibodies in the donor blood react with the A antigenes on the recipient's blood cells?

Similar with AB,but the other way around..

Wed Mar 08, 2006 8:19 am

You should know that now there is NO universal donor and universal recipient anymore. It is old term that we decided not to use it anymore. Blood transfusion should be considered from similar blood type, in which the one comes from relatives is a high priority before we take from the bank.

Wed Mar 08, 2006 7:26 pm

i know that. i read it in my book. So what you are saying is there is some aglutination taking place?

Thu Mar 09, 2006 5:21 am

Yes.

Hey my post above was not for you, it was for people who wrote their question in color blue and red. Of course you already know that statement 8)

Thu Mar 09, 2006 7:09 am

Dr.Stein wrote: Blood transfusion should be considered from similar blood type, in which the one comes from relatives is a high priority before we take from the bank.


I can't understand the above statement. Please make it clear.

From your post I came to the conclusion that blood transfusion can occur from the same blood type to the another.

But in my A&P book (Author Guyton & Hall- you may know ) in the chapter it is clearly written that O is the universal donor and AB is universal recepient.

And in the board exams also we write this concept.

Thu Mar 09, 2006 8:12 am

In the past, type O Blood was given to virtually anyone except those with what was termed 'rare' Blood. Donors of Blood group O were always referred to as 'universal donors.' Today, because of new research and a better understanding of the complex issues regarding immune reaction related to incompatible donor Blood cells, type O Blood is no longer automatically seen as being suitable in most every case.

In AB case, say the one with type AB Blood is transfused with type A Blood. We know that on type A Blood there is antigen A + anti-B. This anti will clump antigen B of the type AB blood. Also, when the one with type AB Blood is transfused with type B Blood. We know that on type B Blood there is antigen B + anti-A. This anti will clump antigen A of the type AB blood. There is an agglutination reaction less or more...
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