Hsu W S, Kao J T, Chen J S
Taiwan Yi Xue Hui Za Zhi. 1989 Apr;88(4):407-9.
The excretion of urinary N-acetyl-beta-D-glucosaminidase (NAG) and Alanine Aminopeptidase (AAP) increases with renal damage. The variation in enzyme activity due to the fluctuation of urine flow rate could almost be eliminated by expressing it as the ratio of enzyme activity to urinary creatinine concentration. The urinary enzyme activities increased not only by tubular damage but also by the reduced creatinine clearance due to glomerular injury. The normal reference values of NAG were 2.84 +/- 2.50U/g creatinine for 24-hour urine and 3.23 +/- 2.76U/g creatinine for random urine. The normal reference values of AAP were 9.71 +/- 6.68U/g creatinine for both 24-hour urine and random urine. Although 128 patients were with abnormal enzymuria, only 39.1%, 52.3%, 83.6%, and 86.7% of the patients were with abnormal serum creatinine, serum urea N, creatinine clearance, and urine protein, respectively. In view of the sensitivity, the determinations of urinary NAG and AAP are suitable for early detection of renal diseases.
尿N-乙酰-β-D-氨基葡萄糖苷酶（NAG）和丙氨酸氨基肽酶（AAP）的排泄量随肾损伤而增加。将酶活性表示为酶活性与尿肌酐浓度之比，几乎可以消除尿流率波动引起的酶活性变化。尿酶活性不仅因肾小管损伤而增加，也因肾小球损伤导致的肌酐清除率降低而增加。NAG的正常参考值为：24小时尿为2.84±2.50U/g肌酐，随机尿为3.23±2.76U/g肌酐。AAP的正常参考值为：24小时尿和随机尿均为9.71±6.68U/g肌酐。虽然128例患者存在酶尿异常，但分别只有39.1%、52.3%、83.6%和86.7%的患者血清肌酐、血清尿素氮、肌酐清除率和尿蛋白异常。鉴于其敏感性，尿NAG和AAP的测定适用于肾脏疾病的早期检测。
