Question

Universal donor blood group is
A) O positive
B) O negative
C) AB positive
D) AB negative

Answer 1

Hint : Universal Donor blood group is that blood group which can be transferred to any other blood group safely. Universal blood groups won't cause any reaction when transfused to a patient with any other blood group.

Complete answer : Normally the blood of persons with the same blood group are transferred to each other when in need, and if it is not available at that time, the blood of a person with universal donor blood donor is transferred to safe life without hesitation.

If we say that blood group A is universal donor, this is not possible because it has antigen A present in it with can harm the patient with blood group B. If we say blood group B is universal donor, the antigen present here is B which will harm when transfused to a patient with blood group A. Now, let’s come to blood group AB, AB cannot be the universal donor because it has both antigens A and B present in it. A person with AB blood group is compatible with AB blood group ones only.
Now, let us finally come to blood group O, say O is the universal donor, so yes, blood group O can be the universal donor because it has neither antigen A nor antigen B present in it. So, it will be compatible with all the blood groups.

But, now the confusion arises, whether blood O with Rh factor positive is the universal donor or the one with negative Rh factor. So, the one with a negative Rh factor will be the universal donor because it has no gene present on it that means it will be the least reactive when transfused. So, the blood group O negative is the universal donor because it has no antigens and no Rh factor present on the surface of RBCs and can be transfused safely to all blood groups.

So, the correct answer is option B.

Note : Blood group O negative is the universal Donor since it can be transferred to people with all the blood groups due to the absence of antigens and Rh factor on the surface of RBCs.