News Release


PHILADELPHIA – When kidneys are removed from deceased organ donors in the United States, they are often subjected to “procurement biopsies” and are discarded if certain abnormalities are seen in the kidney tissue — a practice that worsens the already-severe shortage of transplant-eligible kidneys in the country. However, a large portion of the discarded kidneys would function acceptably if transplanted, according to a new study from a team led by researchers in the Perelman School of Medicine at the University of Pennsylvania and the Paris Translational Research Center for Organ Transplantation.

In the study, published today in the Journal of the American Society of Nephrology, the researchers analyzed biopsy data on a series of 1,103 kidneys discarded in the U.S. between 2015 and 2016. They found that 493 of these kidneys could be matched, in terms of biopsy-evaluated quality and other donor characteristics, to 493 kidneys that were actually transplanted in France, where transplant practice is less restrictive.

The researchers then examined the performance of these 493 kidneys transplanted in France, and found that their survival rates were acceptable — 93 percent at one year, 81 percent at five years, and 69 percent at 10 years — indicating that many donor kidneys in the U.S. are being discarded unnecessarily.

Analyzing a larger set of kidney transplants in France for which biopsy data were available, the researchers concluded that the biopsy data added no value in terms of making predictions of transplant failure more accurate.

“These results highlight a lost transplant opportunity in the U.S., and provide a strong rationale for organ procurement organizations to reduce the practice of obtaining biopsies of deceased donor kidneys,” said study lead author Peter Reese, MD, MSCE, an associate professor of Renal-Electrolyte & Hypertension and Epidemiology in the Perelman School of Medicine at the University of Pennsylvania and a kidney transplant physician at the Penn Transplant Center.

The study was a collaboration involving several medical centers in the U.S., France, and Belgium, co-led by Olivier Aubert, MD, PhD and corresponding author Alexandre Loupy, MD, PhD, of the Paris Translational Research Center for Organ Transplantation.

The shortage of kidneys for transplantation continues to be a public health crisis in the U.S. More than 90,000 patients are waiting for kidney transplants, yet only about 20,000 transplants are performed each year. Annually, nearly 5,000 people on the transplant waiting list die without getting a transplant.

Deceased donors provide roughly two-thirds of transplanted kidneys, but thousands of deceased-donor kidneys are discarded annually in the U.S., due to abnormalities seen in procurement biopsies. Studies suggest that most discards are due to a finding of substantial glomerulosclerosis, a condition that can be caused by age or diabetes, for example, and involves the scarring of small blood vessels in the kidney. However, research also suggests that the reproducibility of procurement biopsy findings is poor.

Moreover, kidney transplants in several European countries are usually done without procurement biopsies and are therefore less likely to be discarded. A study published last year by the same research team found that French transplant centers are much more likely that U.S. centers to accept kidneys from older deceased donors. In fact, the average age of French deceased donors is more than 15 years older than deceased kidney donors in the U.S.

The findings from this new study underscore the notion that pre-transplant biopsies don’t seem to add value to the kidney transplant process, and in fact tend to make things worse by reducing the supply of kidneys that could benefit recipients.

“Transplant center staff should understand that procurement biopsy results only contribute limited meaningful information about kidney quality,” Reese said. “In some cases, those biopsies may add bad information. And unfortunately, those biopsies come at a cost — in terms of delays, dollars and occasionally, complications.”

Other co-authors on the study were Maarten Naesens, Edmund Huang, Vishnu Potluri, Dirk Kuypers, Antoine Bouquegneau, Gillian Divard, Marc Raynaud, Yassine Bouatou, Ashley Vo, Denis Glotz, Christophe Legendre, Carmen Lefaucheur, Stanley Jordan, Jean-Philippe Empana, and Xavier Jouven.

Funding was provided by INSERM, Fondation Bettencourt Schueller, the National Kidney Foundation, and the U.S. Department of Health and Human Services (234-2005-37011C).


Penn Medicine is one of the world’s leading academic medical centers, dedicated to the related missions of medical education, biomedical research, and excellence in patient care. Penn Medicine consists of the Raymond and Ruth Perelman School of Medicine at the University of Pennsylvania (founded in 1765 as the nation’s first medical school) and the University of Pennsylvania Health System, which together form a $9.9 billion enterprise.

The Perelman School of Medicine has been ranked among the top medical schools in the United States for more than 20 years, according to U.S. News & World Report's survey of research-oriented medical schools. The School is consistently among the nation's top recipients of funding from the National Institutes of Health, with $546 million awarded in the 2021 fiscal year.

The University of Pennsylvania Health System’s patient care facilities include: the Hospital of the University of Pennsylvania and Penn Presbyterian Medical Center—which are recognized as one of the nation’s top “Honor Roll” hospitals by U.S. News & World Report—Chester County Hospital; Lancaster General Health; Penn Medicine Princeton Health; and Pennsylvania Hospital, the nation’s first hospital, founded in 1751. Additional facilities and enterprises include Good Shepherd Penn Partners, Penn Medicine at Home, Lancaster Behavioral Health Hospital, and Princeton House Behavioral Health, among others.

Penn Medicine is powered by a talented and dedicated workforce of more than 47,000 people. The organization also has alliances with top community health systems across both Southeastern Pennsylvania and Southern New Jersey, creating more options for patients no matter where they live.

Penn Medicine is committed to improving lives and health through a variety of community-based programs and activities. In fiscal year 2021, Penn Medicine provided more than $619 million to benefit our community.

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