Serum levels of neutrophil gelatinase-associated lipocalin in tumor patients and its diagnostic value for acute kidney injury during gama-ray stereotactic radiosurgery

Objective To assess whether serum neutrophil gelatinase-associated lipocalin(NGAL) can be used for diagnosis of acute kidney injury in tumor patients treated with gama-ray stereotactic radiosurgery(Gama knife).Methods A total of 100 tumor patients admitted to our hospital were treated with Gama knife radiotherapy from May 2007 to Nov.2007.Acute kidney injury(AKI) was defined as the absolute increment over 26.52 μmol/L or a 50% increase of serum creatinine from the baseline.All patients used the low-osmolar nonionic contrast medium before treated with Gama knife.The clinical features and the incidence of AKI were prospectively observed.The serum NGAL levels were prospectively observed in tumor patients with AKI during the treatment with Gama knife and the influencing factors were discussed.Results Twenty-five of the 100 patients developed acute kidney injury.The serum NGAL in AKI group was significantly higher than that of non-AKI group(P0.01) 12 h after intravenous injection of contrast medium;the levels of creatinine were similar between the two groups.48 h after contrast injection,the NGAL and creatinine levels in AKI group were significantly higher than those of the on-AKI group(P0.01).Seven days after Gama knife treatment,the NGAL and creatinine levels were similar between the two groups.At the end of treatment the NGAL levels were similar between the two groups;the creatinine level in AKI group was significantly higher than that in the non-AKI group(P0.05).According to the sensitivity and speciticity of NGAL,ROC curves were drawn: 12 h after injection of contrast,AUC was 0.776(95% CI: 0.675-0.878,P0.05),and for 48 h it was 0.674(95% CI: 0.558-0.789).Conclusion Compared with creatinine,NGAL level 12 h contrast injection allows for earlier diagnosis of AKI,with high accuracy and satisfactory sensitivity and specificity.