Monitoring organophosphate insecticide-exposed workers for cholinesterase depression. New technology for office or field use.
McConnell-R; Cedillo-L; Keifer-M; Palomo-MR
J Occup Med 1992 Jan; 34(1):34-37
The precision and field performance of a new kit for measuring erythrocyte cholinesterase were evaluated. The kit was based on the Ellman assay. The battery operated colorimeter made use of a novel application of a light emitting diode. By adjusting cholinesterase for hemoglobin concentration, it was possible to markedly reduce interindividual variability and the associated false negative cholinesterase tests common to other assays. The study population consisted of 23 pesticide formulators at a factory in Mexico who were exposed to hexachlorobenzene (118741), DDT (50293), and methyl-parathion (298000) during the 2 weeks prior to the evaluation. All workers had normal cholinesterase, and exposed and unexposed workers had similar mean cholinesterase levels. While erythrocyte cholinesterase had a coefficient of variation of 12%, hemoglobin adjusted erythrocyte cholinesterase had a markedly reduced coefficient of variation. The 90% confidence interval resulted in a lower normal limit that was 78% of the upper limit. Even if a preexposure baseline were high normal, but unknown at the time of examination, the supervising clinician could be confident that any person with a normal result would be no less than 78% of baseline. A pesticide applicator poisoned with organophosphates showed markedly inhibited cholinesterase activity. The authors conclude that the kit carries a moderate price, is easy to use in a field setting, and the low variability to the assay should allow improvement in diagnosis, screening, and in the epidemiologic evaluation of exposure.
Pesticides; Agricultural-chemicals; Enzyme-activity; Cholinesterase-inhibitors; Chlorinated-hydrocarbons; Agricultural-workers; Blood-analysis; Testing-equipment; Blood-tests
118-74-1; 50-29-3; 298-00-0
Journal of Occupational Medicine
University of Washington, Seattle, Washington