Urinary N-acetyl beta-D-aminoglucosidase (NAG) may fall on its own and rise if the disease deteriorates further. NAG activity is particularly sensitive to active tubular injury and can be used to monitor early kidney injury and the course of the disease. Elevated NAG can be seen in drug-induced renal injury, diabetic renal injury, hypertensive nephropathy, early monitoring of pregnancy-induced pre-eclampsia, etc. If the patient’s pre-existing condition improves, NAG will decrease. If the patient’s pre-existing condition worsens, such as when suffering from glomerulonephritis, lupus nephritis, diabetic kidney injury and other diseases, the enzyme can be further elevated. Therefore, if NAG does not decrease but increases after treatment, it is recommended to consult a doctor in time, under the doctor’s guidance, improve the relevant examinations, clarify the cause of the disease, and treat the symptoms.