Serum Neutrophil Gelatinase-associated Lipocalin: A Biomarker of Renal Impairment in Hypertensive Patients

Abstract

Background and Aim: Hypertension is one of the leading causes of chronic kidney disease (CKD). Neutrophil gelatinase-associated lipocalin (NGAL) is a novel and sensitive biomarker in acute and chronic renal injury. The present study investigated serum and urinary NGAL as markers of kidney damage in hypertensive and CKD patients. Materials and Methods: This case-control study was performed on 28 hypertensive patients, 28 patients with CKD, and 33 healthy volunteers. Serum and urinary NGAL levels were measured using the ELISA method. Creatinine and urea concentrations were measured by the routine methods. Receiver-operating characteristic (ROC) curve analysis was employed to find the best serum and urinary NGAL cut-off values for detecting renal function. Results: Both serum and urinary NGAL levels were higher in CKD patients than in hypertensive patients and healthy controls (serum NGAL: 193.48±50.62 vs 99.47±26.65 and 48.74±12.07, P<0.001; urinary NGAL: 63.78±16.54 vs 23.24±6.87 and 11.36±3.4, P<0.001 respectively). There was a significant positive correlation between serum and urinary NGAL with serum urea and creatinine. Serum and urinary NGAL levels showed a significant inverse correlation with the estimated glomerular filtration rate. In ROC analysis, serum NGAL had the best diagnostic profile with an AUC of 0.938 (95% CI: 0.865–0.978) and the best cut-off value of 64.61 ng/mL (sensitivity 97.73%; specificity 77.27%. Conclusion: These results revealed that serum NGAL is a reliable marker for early diagnosis of renal injury in hypertensive patients.