Which of the following blood group is Universal Donor?

Appeared in: NIMHANS Nursing Officer - 2019

Explanation

Blood group O is called the universal donor because its red blood cells (RBCs) lack both A and B antigens on their surface.
The absence of these antigens means that when O-group blood is transfused, the recipient's immune system will not recognize the donor cells as foreign.
This prevents an antigen-antibody reaction, known as agglutination (clumping) and subsequent hemolysis (destruction of RBCs), which can be fatal.
Therefore, Group O red blood cells can be safely given to individuals with any other blood type (A, B, AB, or O).

Option A: Blood group A is not a universal donor because its red blood cells have A antigens. If given to a person with group B or O blood, the recipient's anti-A antibodies would attack the transfused cells.
Option B: Blood group B is not a universal donor because its red blood cells have B antigens. If given to a person with group A or O blood, the recipient's anti-B antibodies would cause a transfusion reaction.
Option D: Blood group AB is the opposite of a universal donor; it is the universal recipient. Its red blood cells have both A and B antigens, so it can only be donated to another person with AB blood.

Clinical Relevance

Nursing practice connection: Knowing ABO Blood Group System and Transfusion Compatibility helps nurses interpret findings accurately and avoid errors in routine assessment, medication administration, and patient teaching.
In nursing practice, verifying blood compatibility is a critical safety measure before any transfusion. An error can lead to a severe or fatal hemolytic transfusion reaction.
O-negative blood is a vital resource in emergency departments, trauma centers, and for neonatal transfusions because it can be administered quickly without waiting for cross-matching results when a patient's life is at immediate risk.
What if? If a patient needs plasma instead of red blood cells, the compatibility rules are reversed. A person with AB blood is the universal plasma donor because their plasma contains no anti-A or anti-B antibodies. A person with O blood is the universal plasma recipient.

How to Approach the Question

First, identify the key term in the question: 'Universal Donor'.
Recall the fundamental principle of blood transfusion: the donor's antigens must not react with the recipient's antibodies.
A 'universal donor' must have red blood cells (RBCs) that lack the antigens that could trigger an immune response in any recipient.
Consider the antigens present on the RBCs of each blood group: Group A has A antigens, Group B has B antigens, Group AB has both A and B antigens, and Group O has neither A nor B antigens.
Based on this, conclude that Group O is the only one whose RBCs can be given to anyone without causing an ABO antigen-antibody reaction.
Therefore, select O as the correct answer.

Concept Tested & Keywords

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E6 Physiology Essentials Sembulingam 10e Part 1 pp. 147-149, 146-148

E6 Nursing Fundamentals Potter Perry 12e Part 5 p. 75-77

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