Serum neutrophil gelatinase-associated lipocalin :as a biomarker of renal impairment in hypertensive patients

Hypertension is one of  the leading cause of chronic kidney disease(CKD). Neutrophil gelatinase-associated lipocalin (NGAL) has been known as a novel and sensitive biomarker in acute and chronic renal injury. The present study aimed to investigate serum  and urinary NGAL as a marker of kidney damage in hypertensive and CKD patients.

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 ELISA method. Creatinine and urea  concentrations were measured according to the routine methods. Receiver-operating characteristic (ROC) curve analysis was employed to find the best serum and urinary NGAL cut-off values for detection of the renal function.

Both serum and urinary NGAL levels were higher in CKD patients than in hypertensive patients and healthy controls (193.48 (96.14–263.43) vs 99.47 (29.14–132.21) vs 48.74 (27.09–64.61), P < 0.001; 63.78 (20.00–82.00) vs 23.24 (8.00–33.00) vs 11.36 (2.15–14.26), P <0.001).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 eGFR. In ROC analysis, serum NGAL had the best diagnostic profile with an AUC of 0.938 (95% CI: 0.865–0.978) and a best cut-off value of 64.61 ng/ml (sensitivity 97.73%; specificity 77.27.0%).

These results revealed that serum NGAL is a reliable marker for early diagnosis of renal injury in hypertensive patients.