Serum and urinary beta-2-microglobulin among cadmium-exposed workers.

The effect of ten years' cadmium [Cd] exposure was investigated among a total of 18 workers [ten with previous heavy exposure, three with recent lower exposure and five control workers] by comparing indicators of previous exposure [blood and urinary Cd and beta 2-M] with clinical estimates of renal tubular function. The ten workers still excreted higher concentration of Cd than did the other three workers with low exposure, even after cessation of exposure. Estimates of renal function indicated that most workers among the ten and the three workers did not always exhibit dysfunction. Elevated blood Cd was significantly correlated with elevated serum beta 2-M. The study demonstrated that increased beta 2-M in the urine is not necessarily due to tubular impairment, but may be the result of the increased beta 2-M in plasma exceeding the renal threshold.