Introducing a Cholinesterase Test Kit into Clinical Practice

(NIOSH 2006-2011) This project evaluated the feasibility and functionality of integrating a portable testing kit, the Test-mate ChE test system, into the existing state-wide cholinesterase monitoring program administered by Washington State OSHA (known as WISHA). The aim was to enhance and simplify worker monitoring of pesticide overexposure for certain agricultural workers. We have shown the Test-mate™ kit to be an effective, cost-efficient test that can provide rapid results for workers – important if they are shown to have a ChE depression. Mixed results were obtained from these studies. We showed it is feasible to use the test kit in place of the present commercial lab for measuring plasma ChE depression amongst pesticide handlers, but not for measurements of RBC ChE depression.

Due to the poor agreement between test-kit and State Lab data for RBC ChE, at this time we do not recommend using the test-kit to replace the state designated laboratory for RBC ChE testing. A reactivation procedure using the oxime 2-PAM was also developed and incorporated into the test kit. This procedure can provide additional evidence that a ChE depression resulted from exposure to OP pesticides, provided that blood samples are collected and analyzed within ~24 hours of exposure to pesticide. For the cohort of workers examined in the current study, too much time had elapsed between pesticide exposure and collection of blood samples and the oxime was unable to reactivate ChE activity in these samples. However, the oxime reactivation procedure would be useful for clinical diagnosis of acute poisoning with organophosphorus pesticides, and to guide patient treatment in such cases. The study provided guidance for medical clinics to evaluate clinic-specific issues that interfere with using the test kit. For example, significant barriers include: required certification, training costs, and physical space needed.