While studying compatible blood groups, I found that we only consider the antigens on red blood cells (RBCs) and not the antibodies present in blood plasma. For example

“an AB blood group person can receive blood from persons of any blood group as there are already both antigens, A and B, on the RBCs.”

But why don’t we consider the antibodies already present in the plasma from people with different blood groups?

For example, the O blood group has both anti-A and anti-B antibodies. If this blood is given to an AB person who has antigens A and B, do the antibodies of O not react with the antigens of AB? Or, in other words, how is a person with the AB blood group a universal recipient if he has both antigens(A,B) in the blood, which can react with antibodies(anti-A and anti-B) present in indiduals of other blood groups (A, O, B)?

  • 1
    $\begingroup$ Always remember that plasma is not given while blood transfusion. So if you are giving only RBC of O blood group to the person having AB Blood group it will not react. $\endgroup$
    – Serotonin
    Commented Dec 26, 2017 at 10:40
  • $\begingroup$ Although I answered this question, an older similar question has just surfaced for some reason. (The answer there is also more comprehensive than mine, and some comments more authoratitive.) I therefore flag this as a duplicate and have deleted my answer. (I may add something to the older question.) $\endgroup$
    – David
    Commented Dec 27, 2017 at 16:15


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