Whole blood has similar risks to a transfusion of red blood cells and must be cross-matched to avoid hemolytic transfusion reactions. Most of the reasons for use are the same as those for RBCs, and whole blood is not frequently used in high income countries where packed red blood cells are readily available. However, use of whole blood is much more common in low and middle income countries. Over 40% of blood collected in low-income countries is administered as whole blood, and approximately a third of all blood collected in middle-income countries is administered as whole blood.