Reported October, 2007

BACKGROUND: About 4,000 patients will die each year waiting for a kidney transplant. But a new number-crunching computer program developed at Carnegie-Mellon University (CMU) could help match living donors with patients to save more lives. The biggest advantage of the new software is that it uses a new algorithm that enables more complicated matching by factoring in not just donors, but also the most efficient way to handle three and four way exchanges.

HOW IT WORKS: Many kidney disease patients receive a life-saving organ from a donor who has died -- a process managed by the United Network for Organ Sharing (UNOS). Other patients have living friends or family members willing to sacrifice a kidney -- a process managed by a local transplant center. But sometimes the family member’s or friend’s blood or tissue doesn’t match the patient, so that particular donation isn’t possible. So, hospitals will then attempt to match a donor-patient pair with another willing pair with compatible blood or tissue. This is a typical two-way match. The more donor-patient pairs there are in a pool, the more complicated the matching process becomes. In a three-way match, Donor A gives a kidney to Patient B. Donor B gives a kidney to Patient C. And Donor C gives a kidney to Patient A.

Many kidney disease patients receive a life-saving organ from a donor who has died -- a process managed by the United Network for Organ Sharing (UNOS). Other patients have living friends or family members willing to sacrifice a kidney -- a process managed by a local transplant center. But sometimes the family member’s or friend’s blood or tissue doesn’t match the patient, so that particular donation isn’t possible. So, hospitals will then attempt to match a donor-patient pair with another willing pair with compatible blood or tissue. This is a typical two-way match. The more donor-patient pairs there are in a pool, the more complicated the matching process becomes. In a three-way match, Donor A gives a kidney to Patient B. Donor B gives a kidney to Patient C. And Donor C gives a kidney to Patient A.

The American Mathematical Society and the Mathematical Association of America contributed to the information contained in the TV portion of this report.

If you would like more information, please contact:

Tuomas Sandholm
Carnegie Mellon University
Pittsburgh, PA 15213
(412) 268-8216
sandholm@cs.cmu.edu

American Mathematical Society
Providence, RI 02904-2294
(800) 321-4267
http://www.ams.org

Mathematical Association of America
Washington, DC 20036-1358
(800) 741-9415
http://www.maa.org

DID YOU KNOW?

There are about 70,000 patients on the national kidney transplant waiting lists in the US.

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Tuomas Sandholm