Renal proximal disfunction based on activity of n-acetyl-beta-d-glucosaminidase in urine of patients with kidney failure

N-acetyl-beta-D-glucosaminidase (NAG) urine activities of 63 patients with stable and unstable chronic renal failure have been investigated. The values of NAG activity obtained from these patients were compared with NAG activity of 33 normal controls. Abnormal NAG values (> 70 nmol/mg of creatinine) were found in 60 (95.2%) patients with chronic renal failure and the median of all values was 327.8 nmol/mg of creatinine. It was 14-fold greater than the median of values for normal controls. There were any significant differences of NAG values between the patients with massive proteinuria (> 1.5 g/24 h), moderate proteinuria and those without 24 hour proteinuria or non-significant proteinuria (respectively 423.5 +/- 286.3 vs 414.4 +/- 334.8 vs 453.0 +/- 451.3 nmol/mg of creatinine). There was no significant difference between the two subgroups of patients with NAG values above and below 280 nmol/mg of creatinine in age, gender, serum urea and uric acid levels. However, the incidence of patients with NAG values higher than 280 nmol/mg of creatinine was statistically significant in unstable course of renal insufficiency and raised serum creatinine levels. It is suggested that the measurement of NAG excretion may be helpful to monitor unstable process in renal failure.