Deceased donor kidneys harvested at the start of the weekend are significantly more likely to be discarded than transplanted, a new study finds. Kidney quality does not appear to be the main deciding factor.

“This high discard rate is concerning especially given the worsening organ shortage in the US, but the factors contributing to this are poorly understood,” lead investigator Sumit Mohan, MD, MPH, of Columbia University Medical Center in New York, explained in a press release. “The most commonly cited reason for organ discard is organ quality, but recent analyses by our group suggest that even kidneys of acceptable quality are being discarded at an increasing rate.”

Dr Mohan and colleagues tracked 181,799 deceased donor kidneys recovered for transplantation 2000-2013 using the US Scientific Registry of Transplant Recipients. After mapping the usage of donor kidneys by day of the week, they observed a weekend effect. Compared with donor kidneys procured on weekdays, weekend kidneys (gathered on Friday or Saturday) were 16% more likely to be discarded, even after adjustment for organ quality.

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Remarkably, donor kidneys discarded on weekends were of significantly higher quality than organs discarded on weekdays, based on the Kidney Donor Profile Index (KDPI): 76.5% vs 77.3%. A measure used to estimate graft failure, the Kidney Donor Risk Index figures into the KDPI and accounts for serum creatinine, hypertension, diabetes, age, cause of death, and other relevant patient factors. It does not include organ characteristics, however, such as anatomical abnormalities, injury during extraction, or biopsy findings.

In addition, weekend transplant rates varied by US region, according to results published in Kidney International. More states in the southeast and midwest performed transplants on weekends. States along the Rocky Mountains, Arizona, and Oklahoma, performed the least. 

Weekend kidneys also were more likely to be used by larger transplant centers (performing 100 or more transplants annually), be shared without payback of a kidney of the same blood type to the national pool, and experience shorter cold ischemia times.

Taken together, the findings indicate the presence of roadblocks to weekend kidney usage beyond organ quality. If resource limitations during the weekend are behind the higher discard rates, policy and organizational solutions may help transplant program reduce waste, the researchers concluded.

Further investigation into the short- and long-term outcomes of recipients of deceased donor kidneys may reveal useful information. Currently, no universal guidelines for organ selection exist.


  1. Mohan S, Foley K, Chiles MC, et al. The Weekend Effect Alters the Procurement and Discard Rates of Deceased Donor Kidneys in the United States. Kidney Int. doi:10.1016/j.kint.2016.03.007.
  2. Donor kidneys may be discarded due to ‘weekend effect’ at hospitals [news release]. Elsevier, May 12, 2016.