DONOR-DIRECTED BLOOD PRODUCTS
A relative or friend can donate blood for a specific patient. This technique cannot be used in the emergency setting because it takes up to 48 h to process the blood for use.
This system has some drawbacks: Relatives may be unduly pressured to give blood; risk factors that would normally exclude the use of the blood (hepatitis or HIV positivity) become problematic; and the routine donation of blood for emergency transfusion may be adversely affected. These units are usually stored as PRBC and released into the general transfusion pool 8 h after surgery unless otherwise requested.