Process of Listing with UNOS

The United Network for Organ Sharing (UNOS) had has a federal contract to operate the national Organ Procurement and Transplantation Network since 1986. Livers are donated in the spirit of altruism and are a limited national resource; thus, it is only right that donor livers be allocated in a fair manner.

Federally designated local Organ Procurement Organizations (OPO) facilitate equitable distribution of donor livers and act as a bridge between a donor hospital (a hospital with a patient who is an organ donor) and the local transplant center(s).

It is the policy of UNOS that all potential recipients of organ transplants must be listed on the national UNOS computer waiting list, with the priority for a donor organ determined by factors discussed below. Patients with chronic liver disease must meet "minimal listing criteria" (Child-Pugh class B, or score >= 7, or episode of either variceal bleed or spontaneous bacterial peritonitis) to be listed with UNOS (see Tables 1 and 2 listed below).

How does the UNOS list work? UNOS establishes policies regarding organ distribution and allocation based on broad consensus and periodically amends these policies. The historical allocation scheme has been that the sickest patient who has waited the longest receives the next available liver.

Donor organs that become available in the local area (California Transplant Donor Network, or CTDN, is the OPO serving the Bay Area) are offered to patients on the waiting list of the local transplant centers, with the exception of patients listed as status 1 who may receive organs from anywhere in the entire UNOS region.

When there is not a good match for any patient at a local center, a donor liver is sent out of the local area; conversely, local transplant centers also sometimes receive livers from distant hospitals, particularly for the most ill patients.

In general, a donor is matched to a potential recipient on the basis of several factors: ABO blood type, body size, time waiting, and degree of medical urgency. UNOS utilizes a computerized point system to distribute organs in a fair manner. Recipients are chosen primarily on the basis of medical urgency and time waiting within each ABO blood group.

The average waiting time for a patient to receive a liver once they are listed with UNOS has increased and may be as much as 12 to 48 months depending on disease severity. The waiting time varies according to the blood type, e.g. patients with O blood type wait longer on average, and patients with B blood type wait for a shorter period of time.

Unfortunately, many more patients today who are referred and selected at an appropriate time in the natural history of their disease will deteriorate during the long wait for a donor organ. Local referral physicians and transplant center personnel together support patients approved and listed for transplantation during this crucial waiting period. The medical urgency, or disease severity, policies have undergone revision on a regular basis and are summarized as of January 2003.