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Hematology/Universal Blood donor and Universal blood acceptor


Dear Dr Kulkarni

If the Universal Blood Donor O and Universal Blood Acceptor AB are mixed together, then the mixed blood can be both a universal blood donor as well as Universal Acceptor?
If not, What are the Biological reasons?


Blood group is determined by the presence of antigen type on the surface of RBCs. If antigen A is present then blood group would be A. If B antigen is presnt then blood group will be B.  If both antigens are present then blood group will be AB. If no antigen is present then blood group would be O. Its important to understand when Antigen A is present on RBCs(or blood group is A), then the blood contains antibodies for Antigens of B type( blood group B). Similary Blood group B has antibodies for Antigen A(blood group A), blood group AB has no antibodies(so can accept any type of blood), And blood group O has antibodies for both antigen A and B. SO when you mix universal donor O with universal acceptor AB then blood will have some RBCs of O type and some RBCs of AB type. This type of blood can be universal acceptor but not universal donor because in the mixed blood some portion or % of RBCs are still of AB type(i.e. they have both Antigen A and B on their surface). So when you give this mixed blood(which has some O type RBC and some AB type RBC) to A blood group person the antibodies of his blood will attack the B part of the AB antigen. Conversly when given to B blood group person the antibodies in his blood will attack A part of AB antigen. You can give this blood only to AB person because he has no antibodies to attack AB antigen. Once again you cant give to blood group O person because he has antibodies for both antigen A and B.
I am sending you a link so that you understand the blood typing, crossmatching more clearly. When there is mismatch the RBCs gets lysed(destroyed). Also it may cause internal clotting leading to death.

If you dont understant anything pls let me know. Are you a medical student? If yes please study in detail about rhesus factor also which makes the above picture I gave even more complicated to explain!

Thanking you!


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Dr.Shrinidhi Kulkarni


I can answer all questions related to hematology. RBC, WBC, Platelet and blood forming organs etc and related questions. hematology also includes blood proteins, hemoglobin and disorders related to clotting abnormalities. So questions about all aspects of hematology are welcome!


Working as a Doctor in Primary Health care Centre.

KIMS Banglore

MBBS, Internship in Internal Medicine

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