O Negative (O−) Blood Group
O− is group O with RhD-negative status. Under standard ABO/Rh red-cell compatibility, O− red cells can be used for recipients of all eight basic ABO/Rh groups.
Medical information notice: This article explains general blood-group concepts. Actual transfusion decisions are made by qualified clinical and transfusion-service staff after appropriate testing.
What does O Negative (O−) mean?
O− is group O with RhD-negative status. Under standard ABO/Rh red-cell compatibility, O− red cells can be used for recipients of all eight basic ABO/Rh groups.
Red-cell compatibility
O− red cells are often described as the universal red-cell donor type, particularly for emergency use when the patient’s blood group is not yet known. This does not mean every blood component has the same compatibility pattern.
Why compatibility testing still matters
WHO guidance shows that red-cell and plasma compatibility are different. Blood services therefore select and test components according to the patient and the component being transfused.
Sources
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