BACKGROUND: Neutrophil gelatinase-associated lipocalin (NGAL) is a promising 
biomarker of acute kidney injury. There is a growing body of evidence suggesting 
that NGAL is also a marker of kidney disease and severity in chronic kidney 
disease (CKD). We studied the utility of urinary NGAL in more accurately 
predicting renal function in patients with diabetic CKD.
METHODS: We studied possible relationships between urinary NGAL, estimated 
glomerular filtration rate (eGFR), and proteinuria in diabetic CKD patients and 
in healthy populations.
RESULTS: Urinary NGAL levels were significantly higher in CKD patients than in 
healthy controls (96.0 [2.7 to 975.2] ng/mL vs. 18.8 [1.3 to 81.9] ng/mL, 
P=0.02), and the GFR was lower among CKD patients (49.3 [13.1 to 78.3] 
mL/min/1.73 m(2) vs. 85.6 [72 to 106.7] mL/min/1.73 m(2), P<0.0001). The urinary 
NGAL level showed a significant inverse correlation with GFR (r=-0.5634, 
P<0.0001). The correlation analyses between urinary protein level and urinary 
NGAL levels and GFR were as follows: urine protein and urinary NGAL (r=0.3009, 
P=0.0256), urine protein and GFR (r=-0.6245, P<0.0001), urine microalbumin and 
urinary NGAL (r=0.1794, P=0.2275), and urine microalbumin and GFR (r=-0.5190, 
P=0.0002).
CONCLUSION: From these results, we concluded that urinary NGAL is a reliable 
marker of renal function in diabetic CKD patients. However, urinary NGAL did not 
provide more accurate information regarding renal function than GFR.