User:Heena1990/sandbox

Blood Group O negative.
If you’re O neg, you’re rare! Only 7% of the world’s population is O neg. You’re also the universal red blood cell donor, which means your blood can be transfused to patients with other blood types. (Incidentally, if you are O neg, you can only receive O neg blood.) What makes O neg the universal type is that there are no A, B or D (Rh positive) antigens present on the red blood cells. This is why it’s compatible with other types, and why O neg blood is often used for emergencies and accidents, when there’s no time for blood typing before transfusion.