NAG, hexosaminidase

NAG (HEX) is measured in urine as a non-invasive marker of renal damage and disease. Renal disease causes a progressive deterioration in function which eventually results in renal failure which necessitates either renal dialysis or transplantation. The young are often affected and treatment may therefore be necessary for long periods of time. The kidney is also susceptible to secondary damage resulting from hypertension, diabetes, arthritis and urinary tract infection as well as being vulnerable to nephrotoxic drugs and environmental pollutants. However, the high reserve capacity of the kidney means that over 50% of active renal mass can be lost before there is a measurable change in renal function. Definitive diagnosis of renal disease is often based on the examination of renal biopsy samples or the measurement of serum creatinine which is modified after the disease is well established. However, this procedure is not without risk. There is consequently a proven need for, sensitive, non-invasive tests, as early detection improves the possibility of successful treatment, and at the same time reduces medical costs while improving the prospects of the patients. Such tests are also required for the assessment of new drugs for potential nephrotoxicity, and monitoring for the effect of environmental or occupational toxins (for example, heavy metals or solvents).
Hexosaminidase (NAG) isoenzymes are present in different organs and tissues. The liver, kidney and spleen the acidic A-form and the basic B-form are present. However, in serum the major form is the As-form but two additional intermediate forms I1 and I2 are present. The latter resembles the P-form which is found in the serum of pregnant women. Hexosaminidase is assayed in Genetic Laboratories in suspected cases of Tay-Sach disease and Sandhoff’s disease. The A-form of HEX is absent from Tay-Sach disease which is most commonly found in Ashkenasi Jews.

Key Benefits:
- Early warning of renal damage
- Colorimetric procedure adaptable to any laboratory
- Can be used in conjunction with heat treatment or ion-exchange chromatography in the quantitation of the A and B-forms of hexosaminidase.