Paired kidney donation by shipment of living donor kidneys Segev et al. (1) have shown that the optimum number of paired kidney donor matches can be obtained by a national paired donor program. The same group has further shown that with a large pool of potential donors, paired kidney donation is more effective than listed paired kidney donation, in which live donor kidneys are exchanged for cadaver donor kidneys on a list (2). These important calculations serve to bring to the fore the significant potential of paired dona- tion programs (3), which have now begun on a regional basis in Maryland (4, 5), New England (6, 7) and Ohio (8, 9). They also emphasize the need for a national program, as the potential impact of such a program depends mainly on the size of the pool of donors. Segev et al. (1) showed in their simulation analysis that if highly sensiti- zed patients were willing to travel nationally and mathematical optimization was used, these patients could expect six-fold increase of receiving transplants compared with regional match. As pointed out by Woodle (3), the requirement of the donor to travel large distances will be the prin- cipal deterrent for the program as it separates families, creates anxieties and incurs costs to the family. As a solution to the problem of donors having to travel, we propose here a simple solution: that of shipment of the donor kidney. Shipment of the donor kidney simplifies the logistics as the donor can donate from home at the same transplant center as the recipient. It further reduces social transaction complications in a donor exchange by de-personalizing the donor kidney. The matched kidney arrives by plane from some distant place from a nameless donor who happened to be a good match, much as the zero mismatched cadaver donor kidney arrives today from an unknown donor. The following analysis was performed to further prove that shipping of living donor kidneys is the practical solution to the paired donor exchange. Patients and methods Data from the UNOS Kidney Transplant Registry were utilized for the analysis cited. Eligible patients were those who received their kidney transplant Waki K, Terasaki PI. Paired kidney donation by shipment of living donor kidneys. Clin Transplant 2007: 21: 186–191. ª Blackwell Munksgaard, 2007 Abstract: It is apparent from calculations that for paired kidney donation programs, a national program will provide optimum benefit. To obviate major problems associated with donors traveling long distances, we pro- pose shipping donor kidneys. Evidence is provided from the United Network for Organ Sharing (UNOS) Kidney Transplant Registry, that 14 873 immediate functioning kidneys from deceased head-trauma donors with an average cold ischemia time of 18.3 h had 85.7% three-yr graft survival compared with 87.8% survival of 23 369 transplants from living donors with 2.4 h of ischemia. Grafts from 10 368 deceased donors with 13–24 h cold ischemia time had three-yr graft survival of 82.6% compared with 84.2% for 1153 transplants with up to six h cold ischemia time. After adjusting for major confounding factors, cold ischemia does not signifi- cantly influence graft survival. We conclude that shipment of donor kidneys can be performed safely and will significantly increase paired donor transplants. Kayo Waki and Paul I. Terasaki Terasaki Foundation Laboratory, Los Angeles, CA, USA Key words: highly sensitized kidney patients – kidney transplant – living donor exchange Corresponding author: Paul I Terasaki, 11570 West Olympic Blvd, Los Angeles, CA 90064, USA. Tel.: +1 310 479 6101; fax: +1 310 445 3381; e-mail: terasaki@terasakilab.org Accepted for publication 30 December 2005 Clin Transplant 2007: 21: 186–191 DOI: 10.1111/j.1399-0012.2006.00621.x Copyright ª Blackwell Munksgaard 2007 186