Which blood group is known as the universal donor?

OSSSC Nursing Officer-2021

Applied Physiology

Easy

Appeared in: OSSSC Nursing Officer-2021

Explanation

Blood group O is termed the 'universal donor' because its red blood cells (RBCs) have no A or B antigens on their surface.
The absence of these specific antigens means the recipient's immune system will not recognize the transfused cells as foreign, thus preventing an antibody-mediated attack.
This unique characteristic allows O group blood to be safely transfused to individuals with any ABO blood type (A, B, AB, or O) without causing a major hemolytic reaction.

Option B: Blood group AB is known as the 'universal recipient,' not the universal donor. Its RBCs have both A and B antigens, so it can only be donated to other AB individuals.
Option C: Blood group A is not a universal donor because its RBCs have A antigens. If transfused to a person with type B or O blood, the recipient's anti-A antibodies would attack the donor cells.
Option D: Blood group B is not a universal donor because its RBCs have B antigens. If transfused to a person with type A or O blood, the recipient's anti-B antibodies would cause a transfusion reaction.

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.
Correct blood typing and cross-matching are critical nursing responsibilities to prevent life-threatening hemolytic transfusion reactions. Always verify donor and recipient compatibility before administration.
While O group is the universal RBC donor, O-negative is the true universal donor as it also lacks the Rh(D) antigen, making it the safest choice in emergencies when the recipient's blood type is unknown.
What if? If a patient with blood type B receives type A blood, the recipient's pre-existing anti-A antibodies will bind to the transfused A antigens, triggering massive intravascular hemolysis, which can lead to acute kidney injury, shock, and death.

How to Approach the Question

First, identify the key term in the question: 'universal donor'.
Recall the principles of the ABO blood group system, focusing on which antigens are present on the red blood cells (RBCs) of each blood type.
Understand that a 'donor' provides RBCs, so the critical factor is the absence of antigens on the donor's cells that could react with the recipient's antibodies.
A 'universal' donor must have RBCs that can be given to anyone. This means the RBCs must lack the main antigens (A and B) that could trigger an immune response.
Evaluate the options based on this principle: Type A has A antigens, Type B has B antigens, and Type AB has both. Only Type O has neither A nor B antigens.
Conclude that blood group O is the universal donor because its RBCs are 'unmarked' and won't be attacked by a recipient's antibodies.

Concept Tested & Keywords

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