A new national allocation scheme for adult kidneys in the United Kingdom. United Kingdom Transplant Support Service Authority (UKTSSA) Users' Kidney Advisory Group and its Task Forces.

A new allocation scheme for kidneys from adult cadaver donors was introduced in the UK on July 1st, 1998. The new scheme is based on data from an analysis of factors influencing transplant survival instigated by the Kidney Advisory Group (KAG) of the UKTSSA. A cohort of 6,363 first cadaver allografts performed in the UK between 1986-1993 was used for the analysis with 99.6% one-year follow-up and 97.8% 5-year follow-up. HLA matching was one of a number of factors that were found to influence transplant survival, thus supporting the policy of exchange of kidneys based on matching. The new allocation scheme is based on 3 tiers in which cadaver organs are offered first in Tier 1 to patients with zero HLA antigen mismatches (000 matchgrade), in Tier 2 to favorably matched patients, (matched for HLA-DR and mismatched for a maximum of one HLA-A and one-B locus antigen -100, 010, 110 matchgrades) and remaining kidneys in Tier 3 to non-favorably matched patients. A points score devised by a subgroup of the KAG to reflect natural justice and common sense is used as a discriminator between equally matched patients. The points are based on recipient age, donor-recipient age difference, waiting time, matchability for HLA antigens, sensitization to HLA antigens and the transplant unit balance of organ exchange. The performance of the scheme will be closely monitored, but computer simulations predict that there will be an overall improvement in transplant survival as a result of an increase in well matched transplants.