Adaptations of an acetylthiocholine ester assay of Ellman et al. Optimized, standardized methods are needed to assess exposures and provide a solid basis for risk assessment analyses. Useful adjuncts to ChE measurements are oxime reactivation tests and assay of neuropathy target esterase, an enzyme associated with organophosphate-induced delayed neuropathy. Determination of urinary metabolites compliments, but does not substitute for, the information obtained from blood ChE studies.
Future assays are likely to involve antibodies to OP-protein complexes.
Improvements in techniques permit the detection of small decreases in ChE activities. Whether or not such small decreases in ChE activities can, by themselves, constitute an adverse effect for input into risk assessment analyses is a controversial matter.