Enliven: Nephrology and Renal Studies

Background:
We previously experienced two patients, who were diagnosed with nephrotic syndrome (NS), who did not exhibit a large enough quantity of urine protein
to cause NS and reported the utility of scintigraphy (3). We here in recommend urinary N-acetyl-beta-D glucosaminidase (NAG) as a potential marker
for the diagnosis of these NS.

Patients and Methods:
The correlations between the concentrations of serum creatinine (SCr), total protein (TP), albumin (Alb), total cholesterol (TC), both the urinary protein/
creatinine ratio (UP/C) and urinary NAG/creatinine ratio (NAG/C) were evaluated in a total of 44 adult patients with NS.

Results:
The NAG/C reveal a moderate correlation with the SCr (R = 0.46) and Alb concentrations (R = -0.42) and the UP/C (R = -0.49), whereas the correlation
between the UP/C and the Alb concentration was weak (R=-0.28).The TC concentration showed a relatively strong negative correlation with the
Alb concentration (R= -0.55) and a positive correlation with the UP/C (R = 0.38); however, no correlation was observed between the TC and NAG
concentrations (R = 0.12).

Discussion:
The increased urinary excretion of NAG in glomerular diseases was shown to be due to an increased release by the damaged renal tubular cells; however, increased filtration across the damaged glomerular capillary wall was not observed.

In this study, the NAG/C tended to correlate with the Alb concentration more strongly than with the UP/C. These results suggested that NAG maybe a
better and earlier marker of hypoalbuminemia, possibly due to a large amount of protein leakage through the glomerulus than the amount of protein in
the urine.