Distribution of urinary N‐acetyl‐beta‐D‐glucosaminidase and the establishment of reference intervals in healthy adults

BACKGROUND: Urinary N‐acetyl‐beta‐D‐glucosaminidase (NAG) plays an important role in the early diagnosis and progression of diseases related to renal tubular injury. We detected the urinary NAG concentration, assessed the preliminary statistics of its distribution, and established reference intervals for healthy adults in China using the rate method. METHODS: A total of 1,095 reference individuals (aged 20 to 79 years) met the requirements for inclusion in this study. Urinary NAG concentrations were detected using an AU5800 automatic biochemical analyzer with its matched reagents. The Kolmogorov‐Smirnov test was used to analyze the normality of the data. According to the guidelines of C28‐A3 and WS/T 402‐2012, the reference intervals of urinary NAG were established using the nonparametric percentile method (unilateral 95th percentile). RESULTS: The urinary NAG data showed a non‐normal distribution. The distribution of urinary NAG was significantly different by sex and age. Therefore, the reference intervals of urinary NAG were established using the rate method: males (aged 20–59 years) <19.4 U/L (90% CI: 18.0–20.3 U/L); males (aged 60–79 years) <22.3 U/L (90% CI: 20.2–22.6 U/L); females (aged 20–59 years) <15.7 U/L (90% CI: 15.2–16.5 U/L); and females (aged 60–79 years) <21.4 U/L (90% CI: 20.3–22.3 U/L). CONCLUSIONS: We established preliminary reference intervals of urinary NAG for healthy adults in China to provide guidance for health screening, auxiliary diagnosis, and treatment monitoring of renal tubule‐related diseases.