Current status of the external quality assurance programmes of the German Society for Occupational and Environmental Medicine.

Due to a technical rule issued by the Ministry of Labour, in Germany toxicological analysis in blood and urine for biological monitoring must be carried out under quality assurance. Since 1982 the German Society for Occupational and Environmental Medicine has offered 13 intercomparison programmes. The 1994 round robin considered 7 metals and 5 solvents in blood, 12 organochlorine compounds in plasma and 14 inorganic, as well as 11 organic, compounds in urine in the occupational and in the environmental exposure range. Reference values and tolerance ranges are established by reference laboratories. Successful participation was certified if the results for 2 concentration adjustments were in tolerance range (assigned value +/- 3 S.D.). In 1994 in 119 laboratories the percentage rate of accurate results was 59%. This mean success rate is in agreement with the last 12 round robins.