The number of people needing organ transplants in the United Kingdom is greater than the number of donor organs available.
This means there has to be a system to ensure that patients are treated equally and that donated organs are allocated in a fair and unbiased way based on the patient's need and the importance of achieving the closest possible match between donor and recipient.
All patients who are waiting for transplants are registered on the National Transplant Database.
Rules for allocating organs are determined by the medical profession in consultation with other health professionals, the Department of Health and specialist advisory groups.
The blood group, age and size of both the donor and recipient are all taken into account to ensure the best possible match for each patient.
For kidney transplant patients, tissue type match is also a consideration. A review of the effects of tissue matching show that a good tissue type match with the donor is important for some patients, but less so for others.
A computer program is used to identify the best matched patient, or alternatively, the transplant unit to which the organ is to be offered.
Organ Donation and Transplantation Directorate within NHSBT monitors the allocation procedure and any cases where the rules have not been followed are reported to the director of the transplant unit concerned, the chairman of the appropriate advisory group and the director of Organ Donation and Transplantation.