[Medical prevention in exposure to lead].

The action of lead on the intermediary metabolism, especially on the synthesis of heme, the red blood cell pigment, is well documented. Therefore biological monitoring of lead exposed persons by means of the urinary metabolites of porphyrin metabolism is very valuable. Biological monitoring through the urinary metabolite - aminolevulinic acid (ALAU) has been put to extensive use for over ten years by the Swiss National Accident Insurance Fund (Suva). At present there are over 3000 workers in 100 factories which are periodically screened for this metabolite. Urinary analyses are carried out at regular intervals of 2, 4 or 6 months according to the lead exposition with additional medical examinations once or twice a year. Due to biological monitoring, technical improvements and personal hygiene there have been no further lead poisoning recently in industrial plants supervised by Suva.