Indicators of renal effects of exposure to cadmium: N-acetyl-beta-D-glucosaminidase and others.

The renal effects of cadmium (Cd) have been studied in industrial workers exposed to Cd and inhabitants of Cd-polluted districts, as the kidney is a critical organ in exposure to Cd. Several biological indicators of Cd have been proposed including N-acetyl-beta-D-glucosaminidase (NAG) and beta 2-microglobulin (BMG) in urine for the detection of early renal effects. The average concentrations of Cd in urine samples were over 10 micrograms/g.creatinine in classic researches. Even in the industrial field, this exposure level is now hardly observed in Japan and western countries. The situation is the same with inhabitants in general living in a Cd-polluted district. From the viewpoint of consistency of the association, the relationship between Cd and NAG has become fairly definite. Stability in the pH change, simplicity, low cost and the reliability of measurements were also satisfactory. NAG is one of the recommended tools for detecting minimum renal effects under 10 micrograms/g.creatinine of Cd.