*4.1.7. N-acetyl-b-d glucosaminidase*

N-acetyl-b-d glucosaminidase (NAG) is a lysosomal enzyme produced in proximal tubular epithelial cells. The levels increased during kidney injury, a marker of proteinuria both in patients with diabetes and in patients with SCD [115, 133]. Sundaram et al. [57] showed that urine NAG activity was higher than baseline levels (>2 U/l) and worse in the presence of albuminuria. The elevations in NAG may precede moderately increased albuminuria, a likely diagnostic tool for early renal damage.
