Diagnostic utility of urinary neutrophil gelatinase associated lipocalin (µNGAL) in predicting the severity of acute kidney injury

Introduction: To assess the diagnostic utility of uNGAL (urinary Neutrophil gelatinase-associated lipocalin) in predicting the severity of AKI and also to study its association with renal outcome at 3 months. Methods: In this prospective single-center cohort study, uNGAL was measured in patients with AKI at admission and at 90 days. Severe AKI was defined as a composite outcome of either death or renal replacement therapy (RRT) requirement during hospital stay. Renal outcomes at 3 months were categorized into complete recovery and nonrecovery patients. Results: Of 53 enrolled patients, 42 completed the study, of which 20 patients recovered. Recovery was better in young and female patients, with lower uNGAL values at admission. Patients with severe AKI had a higher median uNGAL concentration when compared with nonsevere AKI ( P = 0.007). Higher median uNGAL values were observed in AKI patients requiring inotropes and RRT. The area under the curve (AUC) of uNGAL (0.73) with sensitivity of 84% and specificity of 63% and serum creatinine (0.75) with sensitivity of 62% and specificity of 79% to predict the severity of AKI was similar. However, the AUC of uNGAL (0.76) with sensitivity of 58% and specificity of 86% was better than the AUC of serum creatinine (0.6) to predict renal recovery at 90 days. Conclusions: Urine NGAL levels were raised in mild to severe AKI. uNGAL is not superior to serum creatinine in predicting the severity of AKI during hospital stay. However, it is superior to serum creatinine in predicting renal recovery at 90 days.