In many diseases of the kidneys, N-acetyl-β-D-glucosaminidase (NAG) in the urine is excreted in large quantities. A significant increase in NAG activity is observed at the primary and secondary kidney damage, heavy metal poisoning, kidney transplantation, kidney tumor, hypertension, preeclampsia in pregnant women, diabetic nephropathy, polycystic kidneys, glomerulonephritis. Commercial kits have been developed to measure the activity of NAG c using a colorimetric (biochemical) and enzyme-linked immunosorbent (ELISA) methods of research.