[Monitoring indexes for early renal injury in the workers exposed to mercury].

Objective: To study the diagnostic method for early renal injury in the workers exposed to mercury (Hg).

Methods: The contents of urinary Hg were determined by chemical method. Urinary microalbumin (mALB), beta(2)-microglodulin (beta(2)-MG) and retinol binding protein (RBP) levels were measured with total quantitative enzyme immunoassay. The activities of urinary N-acetyl-beta-D-glucosaminidase (NAG) and gamma-glutamyl transferase (gamma-GT) were determined by rate methods. Urinary creatinine (Cr) was measured by using picric acid method.

Results: The levels of urinary BRP, beta(2)-MG, NAG and gamma-GT in exposed workers [(439.7 +/- 201.4), (141.4 +/- 56.3) micro g/g Cr and (12.3 +/- 5.7), (60.3 +/- 18.5) U/g Cr respectively] were significantly higher than those in controls (P < 0.05, P < 0.01). The levels were increased gradually with the increasing contents of urinary Hg. The positive detection rate for single or two combined indexes was rather lower whereas that for 4 combined indexes was as high as 85.5%. A positive correlation was noted between the contents of urinary Hg and urinary BRP, beta(2)-MG, NAG and gamma-GT (r: 0.466, 0.379, 0.323, 0.311, P < 0.05). Urinary RBP was correlated to urinary beta(2)-MG, NAG and gamma-GT (r: 0.362, 0.354, 0.332, P < 0.05).

Conclusion: Combined detection of urinary RBP, beta(2)-MG, NAG and gamma-GT is a sensitive method for the diagnosis of early renal injury in the workers exposed to Hg.