Urinary neutrophil gelatinase-associated lipocalin rapidly decreases in the first week after kidney transplantation

Background Recipient delayed graft function, which is defined as dialysis in the first week after transplantation, is one of the most common early complications after kidney transplantation. This study aimed to evaluate the daily changes in renal function-related biomarkers in the first week post-transplant. Methods A total of 72 kidney transplant recipients were retrospectively included in this study. Clinical and laboratory data were collected daily during the first week post-transplant, including urinary concentrations of neutrophil gelatinase-associated lipocalin (NGAL), serum concentrations of NGAL, creatinine, urea nitrogen, uric acid (UA), beta 2-microglobulin, cystatin C, and estimated glomerular filtration rate (eGFR). Results There were no significant differences in urea nitrogen (P = .375), UA (P = .090), and cystatin C (P = .691), while urinary NGAL (P < .0001), serum NGAL (P < .0001), creatinine (P < .0001), beta 2-microglobulin (P < .0001), and eGFR (P < .0001) were statistically significant in the first week post-transplant. In comparison with serum NGAL (P < .0001), creatinine (P < .0001), beta 2-microglobulin (P = .001), and eGFR (P = .001), the change ratios of urinary NGAL changed the most between day 1 and day 2 after renal transplantation, while the changing degree of urinary NGAL showed no significant difference compared with these indicators between day 1 and day 7 after kidney transplantation. Conclusion Urinary NGAL is a sensitive marker for indicating renal function. Urinary NGAL combined with other markers can be more helpful for evaluating renal function in the first week following kidney transplantation.