Organs for transplantation can come from either living donors or deceased donors. Deceased donors are most often (>90% of the time) persons who are brain dead, and through their prior consent or the consent of their families, have made the heroic decision to be an organ donor.

The supply of deceased donor organs is unfortunately not nearly enough to transplant everyone. During recent years, the transplant community has made a big effort to use every possible organ from every donor.  Not every donated kidney is perfect, but transplant doctors have long wondered whether kidneys that were previously not considered could be used successfully if they were matched with the right recipients. Over the years, the number of donors over the age of 50 has increased by 30% and the number of donors suffering stroke has also increased. The number of patients on the wait list has increased over 200%. Through a changed approach, kidney transplantation is now available to more people and has changed the way organs are offered. There are now two distinct groups of organ donors; the standard criteria donor (SCD) and the expanded criteria donor (ECD).