engleski

Cholinesterase activity assays : an overview of procedures suggested for human whole blood analysis

Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) activities in human blood are biomarkers of exposure to organophosphates or carbamates. Since Ellman in 1962 described a spectrophotometric method with thiocholine substrates and DTNB as the thiol reagent, the method became widespread either in its original version or with some modifications. Procedures for BChE activities in plasma or serum have been validated, and used for many years. This is not the case for the assays of AChE and BChE in whole blood. However, suggestions concerning improvement and standardization have been presented at each CBMTS meeting since 1994. The following procedures for the assay in whole blood have been discussed: to measure AChE plus BChE activities with ATCh, BChE with butyrylthiocholine (BTCh) and calculate AChE from the difference, to apply three substrates for the differentiation of AChE from BChE, to use ATCh plus ethopropazine (a selective BChE inhibitor) for the AChE assay and BTCh for BChE, or to measure activities with ATCh in the presence and absence of ethopropazine (for AChE activity) and calculate BChE from the difference. Suggestions included normalization of AChE activities to the hemoglobin content. No interlaboratory quality control studies have been conducted so far concerning AChE and BChE assays in whole blood.

acetylcholinesterase; butyrylcholinesterase; overview on assays in whole blood; inhibition by organophosphates

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