Future approaches to expand the organ donor pool with marginal and nonheartbeating donors, will be dependent upon prospective organ evaluation. Restoration of metabolism by preservation at warmer temperatures could potentially provide the window for such evaluation. Using a small bovine model, kidneys were subjected to either < 15, < 30 or < 60 minutes of warm ischemia (WI) followed by cold ischemia (CI) in ViaSpan. After WI and CI, kidneys were transitioned to a warm temperature perfusion (30 degrees C to 32 degrees C) using exsanguinous metabolic support (EMS) technology. Restored renal metabolism and function was assessed by oxygen consumption, glucose consumption, urine production, glomerular filtration rate, and hemodynamic characteristics. The results of this study suggest that it is feasible to distinguish viable from nonviable organs ex vivo by assessing renal metabolism and function during warm preservation using EMS technology.