Comparison of Serum Neutrophil Gelatinase-associated Lipocalin (NGAL) with Serum Creatinine in Prediction of Kidney Recovery after Renal Transplantation

BACKGROUND Because of some insult to kidney during transplantation, assessment of kidney function after the procedure is essential. It would be ideal to find a marker better than creatinine to early predict the acute kidney injury. OBJECTIVE To compare with creatinine the predictive value of serum neutrophil gelatinase-associated lipocalin (NGAL) in detecting kidney recovery after renal transplantation. METHODS We studied 33 patients who received kidney transplantation (deceased [n=20] and live [n=13]) during a 6-month period in 2010. Serum NGAL and creatinine, hemoglobin, and blood glucose were measured at 0, 12, 24, 48, and 72 hours after transplantation. The need for dialysis and kidney function in one week were studied. RESULTS There were 16 men and 17 women with the mean±SD age of 36.3±12.2 (range: 14-58) years. Of the studied patients, 6 had delayed graft function (DGF; hemodialysis within the first week of transplant); 9 had slow graft function (SGF; serum creatinine reduction from transplantation to day 7 <70%), and 23 had immediate graft function (IGF; reduction in serum creatinine ≥70%). At any time, serum NGAL, and creatinine levels were significantly higher among patients with DGF (p=0.024) and SGF (p=0.026) compared with those with IGF. However, in those who got IGF vs non-IGF, serum creatinine levels were not significantly different (p=0.59) but serum NGAL levels differed significantly(p=0.020). Receiver-operating characteristic (ROC) curve and area under curves (AUCs) of serum NGAL and serum creatinine levels on the first post-transplantation day had similar significance in predicting the patient's need to dialysis in the first week. However, using AUC of serum creatinine was not helpful in predicting non-IGF, compared to serum NGAL. The AUCs of the serum NGAL were 0.70 (95% CI: 0.52-0.89) and 0.76 (95% CI: 0.59-0.93) after 12 and 24 hours, respectively (p<0.05). The highest AUC (0.82) was attributed to serum NGAL of 24 hour (p=0.002). CONCLUSION Serum NGAL level especially 24 hours post-transplantation, seems to be an early accurate predictor of both the need to dialysis and slow graft function within the first week of kidney transplantation.