Creatinine reduction ratio and 24-hour creatinine excretion on posttransplant day two: simple and objective tools to define graft function.

To devise objective criteria for early diagnosis of delayed graft function (DGF), 59 adult living donor kidney transplants with immediate graft function (IGF) and 51 cadaveric kidney transplants were investigated for creatinine reduction ratio (CRR2) from posttransplant day 1 to day 2 and 24-h urine creatinine excretion (UC2) on day 2. The mean CRR2 in living donor transplants was 53% (SD +/- 11); the distribution of CRR2 was gaussian, and all of them had UC2 >1000 mg. Criteria for DGF were developed on the basis of living donor transplant: CRR2 < or =30% (2SD below 53%) +/- UC2 < or =1000 mg. Overall, 24 cadaver transplant recipients (47%) developed DGF (CRR2 < or =30%); 13 patients (25%) had mild DGF (UC2 >1000 mg), and the remaining 11 (22%) had severe DGF (UC2 < or =1000 mg). All the patients with severe DGF had a measured creatinine clearance <25 ml/min on day 7, and 8 of 11 were dialyzed within the first week of transplantation. Patients with IGF and mild DGF had a creatinine clearance of > or =25 ml/min on or before day 7, and none of them were dialyzed. Calcineurin inhibitors were avoided or delayed in five patients with mild DGF and all patients with severe DGF. In conclusion, diagnosing DGF within 48-h after transplantation is simple and may be valuable in the management of these patients.