Advertisement

What is meant by a universal blood donor?

Individuals with the blood group O Rh negative are called “universal donors” because their red blood cells can be transfused to people of all blood groups. This is why the Red Cross is constantly recruiting donors whose blood type is O Rh negative.
A universal blood donor is someone whose blood type is O negative. Blood type is a designation of two sets of proteins (called antigens) on the outside of red blood cells. One antigen type is the A, B, O type and the other is the Rh type (either positive or negative). 

Type O blood lacks antigens on the outside of the red blood cells. This means that our immune system will not react to the blood because there is no antigen to react against. Similarly, Rh negative blood lacks the Rh antigens on the outside of the blood cells, so once again there are no proteins for our immune system to react against. This lack of antigens means that type O negative blood can be transfused in people of any blood type; hence, the term universal blood donor.

Continue Learning about Blood Basics

Uncle Sam Needs You! To Donate Your Blood
Uncle Sam Needs You! To Donate Your Blood
Giving blood to people who desperately need it is an essential part of modern medicine. The first documented vascular transfusion came in 1667 when a ...
Read More
Step Up: Take Your Blood Pressure Meds and Save Your Life
Step Up: Take Your Blood Pressure Meds and Save Your Life
Q: How can I convince my husband to take his high blood pressure medicine? Help! Katie J., Sioux Falls, SD A: Katie, you’re right to be concerned—un...
Read More
Can I donate blood if I have been incarcerated?
American Red CrossAmerican Red Cross
Persons who have been detained or incarcerated in a facility (juvenile detention, lockup, jail, or p...
More Answers
What are the symptoms of decreased blood flow in the neck?
Brigham and Women's HospitalBrigham and Women's Hospital
When the neck arteries (carotid arteries) become occluded, symptoms such as dizziness, confusion...
More Answers

Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.