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Blood types, agglutinins, and agglutinogens

Discussion in 'MCAT Study Question Q&A' started by junkct, 01.02.09.

  1. junkct

    junkct

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    Type A blood has A agglutinogens and anti-B agglutinins, so it cannot accept Type B or AB blood, but can accept Type A or O blood.

    Type B blood has B agglutinogens and anti-A agglutinins, so it cannot accept Type A or AB blood, but can accept Type B or O blood.

    Type AB blood has A & B agglutinogens, but NO agglutinins, so it can accept Type A, B, AB, or O blood (also called the "universal acceptor").

    Type O blood has NO agglutinogens and anti-A and anti-B agglutinins, so it cannot accept Type A, B, or AB blood, but can accept Type O blood (also called the "universal donor").


    However, if you introduce Type O blood into a patient with A, B, or AB blood, wouldn't the anti-A and anti-B agglutinins cause the patient's blood to agglutinate?
  2. doxycycline

    doxycycline

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    the antibodies attack the antigens so someone with type A blood that receives O blood wont attack it bc O blood has no antigens on it.
  3. Charles_Carmichael

    Charles_Carmichael Moderator Emeritus Bronze Donor

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    Transfusing blood doesn't necessarily mean you're transfusing plasma (which contains the proteins present in blood) from the same source. That's sort of how I always saw it.

    So if an AB blood type person is getting blood from a type O, he's probably not going to be getting the plasma from a type O person. So he wouldn't get the anti-A and anti-B antibodies during the transfusion.

    If you look at just plama compatibility, type O are the universal acceptors and type AB are the universal donors; the opposite of red blood cell compatibility.
  4. futuredoctor10

    futuredoctor10

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    Type A blood has A antigens [on the surface of the blood cells].
    -it cannot accept Type B or AB blood, but can accept Type A or O blood.
    -Type B or AB blood has B antigens which are BAD. not sure what binds to them tho

    Type B blood has B antigens.
    -it cannot accept Type A or AB blood, but can accept Type B or O blood

    Type AB blood has A + B antigens.
    -it can accept A, B, AB, and O blood: universal acceptor

    Type O blood has no antigens.
    -it cannot accept A, B, or AB blood/ it accepts only O blood: universal donor

    If you introduce Type O blood into a patient with A, B, or AB blood:
    The Type O blood has no A or B antigens. Therefore, nothing binds to the blood and it can be introduced into a patient with A, B, or AB blood.

    This is the same as doxycycline says above.

    Questions
    Is the above explanation I have posted overly simplistic, wrong, or correct?
    I learned the A blood has A antigens, AB blood has A+B antigens.

    What are agglutinogens and anti-A/anti-B agglutinins?
  5. doxycycline

    doxycycline

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    i remember seeing agglutinogens on a practice aamc cbt.
  6. Charles_Carmichael

    Charles_Carmichael Moderator Emeritus Bronze Donor

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    I might have misread the question but if I understood what junkct was asking, it looked like he was asking about what would happen if whole blood (cells, plasma, the whole shebang) were transfused and that's the question I answered. Yes, if a type AB person recieves plasma from a type O person, there would be agglutination because the anti-A and anti-B antibodies are in dissolved in the plasma.

    The other two posters are right in saying why transfusion of red blood cells from a type O person to a type AB would not result in transfusion (because no anti-A and anti-B antibodies are transferred). Do you see what I'm saying?

    Futuredoctor10, your explanation is correct for blood transfusion. An agglutinogen is an antigen that stimulates production of agglutinin, which could be an antibody or another substance that causes agglutination to occur. So these A and B antigens are agglutinogens and the antibodies against them are agglutinins.
  7. futuredoctor10

    futuredoctor10

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    Ohhhh ok, that makes sense now. Initially those terms had me so confused!
  8. junkct

    junkct

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    ooh interesting.. I didn't know that blood transfusions involved only the blood cells and not the plasma. I guess that info might be useful to me in the future...
  9. Charles_Carmichael

    Charles_Carmichael Moderator Emeritus Bronze Donor

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    Most of the time, when someone donates blood, the blood is fractionated into its different components: RBCs, platelets, plasma, etc. So yea, depending on the situation, people may receive only only the RBCs or only the clotting factors or only plasma, etc. Packed RBC transfusion is the most common component that's transfused, I think.

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