Delayed graft function (DGF) occurs in 20-50% of renal transplants and is a complication that can affect graft survival. The creatinine reduction ratio (CRR) has been the gold standard for defining DGF. Urinary neutrophil gelatinase-associated lipocalin (NGALu) is an early marker of acute kidney injury. The aims of this study were to describe the behavior of NGALu in deceased-donor renal transplant recipients and to compare this indicator with the CRR for the early detection of DGF. Methodology:This was a prospective cohort study, in which NGALu levels were assessed at 1, 12, 24 and 48 hours after renal transplantation and compared with the daily CRR. Descriptive statistics and nonparametric tests were performed. The best cutoff points and the optimal assessment times for both markers were explored; a comparison of the receiver operating characteristic (ROC) curves for the NGALu level and the CRR was carried out to diagnose DGF.Results:Sixty-one patients were included in the study, 54.8% male and 91.9% first transplant recipients, with a median age of 36.5 years and a median cold ischemia time of 15 hours. DGF occurred in 12 patients and 4 patients required dialysis in the first week. NGALu levels at all the cut-off points were higher in patients with DGF (p=0.49, p=0.0321, p=0.0421 and p=0.0035, respectively). NGALu>120 ng/ml at 48 hours predicted DGF with a sensitivity of 75% and specificity of 67.8%. A CRR of 59% best discriminated DGF, with a sensitivity of 91 % and specificity of 83% at 48 hours. In comparing the ROC curves for the NGALu level and the CRR, the CRR was a better marker.Figure: No Caption available.The cut-offs that were chosen to categorize NGALu and the CRR were 500 ng/ml and 50%, respectively. Using a logistic regression for the adjusted DGF, the odds ratio (OR) of having a positive value was 6.77 for NGALu [CI 1.10 to 41.69] and 18.88 for the CRR (CI 3.33 to 107.08). Conclusion: NGALu levels measured at 48 hours after renal transplantation predict DGF and need for dialysis; however, this marker was not superior to the CRR for early detection.