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INTERLABORATORY COMPARISON OF CHOLINESTERASE ASSAY MEASUREMENTS
Citation:
Marden, B., A. Fairbrother, AND J. Bennett. INTERLABORATORY COMPARISON OF CHOLINESTERASE ASSAY MEASUREMENTS. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/J-95/399, 1994.
Description:
Twelve wildlife toxicology laboratories participated in an interlaboratory survey of cholinesterase (ChE) assays to determine comparability of absolute ChE values and estimates of ChE inhibition from organophosphorus insecticide-dosed birds and to examine the type and consistency of methods employed by laboratories for the measurement of ChE. upernatants of brain from northern bobwhite quail (Colinus virginianus) were prepared from untreated (UT) and methyl parathion (MP)-treated birds. ssays also were conducted on a commercial preparation of acetylcholinesterase from an electric eel. ll laboratories performed the ChE assays using the colorimetric assay with temperature and read time varying by laboratory. here was substantial variation in results of ChE analyses among participating laboratories. ifferences were partially explained by differences in the methods employed for the analysis ChE. ssay temperature and duration appeared to affect the absolute values the most. owever, differences in reported ChE activity values existed even when methods were very similar. hese results do not support the concept of using published normal ChE values from other laboratories to assess ChE inhibition in field-collected samples.