Prevalence of congenital deficiency in serum cholinesterase.

The most economical blood test for the monitoring of workers who are exposed to organophosphate pesticides is serum cholinesterase; however, serum cholinesterase can be affected by conditions other than pesticide exposure. The results of studies in Europe indicate a 4% prevalence of congenital serum cholinesterase deficiency. Prevalence rates in the United States have not been reported. In this study, 127 workers who were part of an employee health program were evaluated. Workers who had decreased serum cholinesterase levels on baseline testing before pesticide exposure were evaluated for a congenital deficit in serum cholinesterase. Five (3.9%) individuals had baseline measurements below the laboratory normal reference value: 4 (3.1 %) were heterozygote for the deficiency, and the remaining individual did not return to test for the genetic deficiency. No one was found to have the homozygote deficiency. The prevalence of congenital deficiency in serum cholinesterase in a midwestern population was 3.1-3.9%. We found it useful to incorporate the knowledge of who has a congenital deficiency into our employee health program, the purpose of which is to monitor workers who spray organophosphates.