Application of plasma neutrophil gelatinase-associated lipocalin as an emerging biomarker in the early diagnosis of acute renal injury following renal transplantation

Objective To study the prognostic role of plasma neutrophil gelatinase- associated lipocalin (NGAL) early after renal transplantation. Methods A total of 37 kidney recipients were enrolled from Department of Organ Transplantation, Guangdong Second Provincial General Hospital within a 12-month period of time. Plasma NGAL was measured immediately before and at 6 and 12 h post-transplantation. Changes of serum creatinine were documented daily within the first week post-operation. Acute kidney injury (AKI)/graft rejection during the first week after transplantation was the outcome variable. Results The levels of serum NGAL in the 37 patients were (311.14±102.69), (317.81±107.28) and (312.16±134.80) μg/L respectively immediately before and at 6 and 12 h post-transplantation. There was no significant difference in serum NGAL levels before and 6 h or 12 h after operation (P=0.70, and P=0.96). There were no significant differences in gender and age between the two groups (P=0.29, and P=0.20). There was significant difference in creatinine levels between the AKI group and the non-AKI group (P=0.002) and between pre-operation and 6 or 12 h postoperation. The preoperative levels of serum NGAL in AKI group and non-AKI group were (333.58±116.30) and (300.36±96.15) μg/L (P=0.36), and those were (383.3±147.16) and (286.32±65.97) μg/L (P<0.01) at 6 h, and (437.33±164.16) and (252.08±57.53) μg/L (P<0.001) at 12 h after operation. The sensitivity and specificity of serum NGAL (317 μg/L at 12 h after operation as the cutoff value) predicting AKI was 100% and 92% respectively, which was much better than that of serum creatinine at the corresponding time point (sensitivity=66.7%, and specificity=61.9%). Conclusion Plasma NGAL, particularly at 12 h after transplantation, is a very sensitive and specific biomarker for predicting AKI. Key words: Kidney transplantation; Neutrophil gelatinase-associated lipocalin; Serum creatinine; Acute kidney injury