Which blood type is considered the universal donor?

Blood type O negative is considered the universal donor because it can be transfused to patients of any blood type. This is due to the absence of A and B antigens on the surface of red blood cells, which reduces the risk of an immune reaction. However, type O negative individuals can only receive blood from other O negative donors. Universal donors are crucial in emergency situations where there may not be time to determine the recipient's blood type. Type AB positive is considered the universal recipient because individuals with this blood type can receive red blood cells from any blood type.