Use of cholinesterase activity in the diagnosis of acute intoxications by organophosphorus and carbamate insecticides

Objective. The measurement of cholinesterase activity (ChE) is a rapid and inexpensive test used in the diagnosis of intoxications by organophosphorus and carbamate insecticides. As the interpretation by laboratories entails reference values for each species, the present study was aimed to establish normal ChE activities in blood, brain and retina of several species of domestic animals by the use of the Ellman method. Materials and methods. Brains and eyeballs were obtained from Medellin's central slaughterhouse, while blood samples came from animals referred to the clinical diagnostic laboratory from the University of Antioquia. Results. The mean (± SD) of blood ChE activity, expressed as ?moles of iodide hydrolyzed acetylthiocholine/min/mL, were 2.4±0.2, 1.5±0.3, 1.9±0.3 and 2.5±0.2 for canines, felines, equines and bovines, respectively. In the brain, ChE activity (?mol/min/g wet weight) was 4.0±0.4, 5.4±0.3 and 4.9±0.3, in bovines, porcine, and canines, respectively. The bovine retina showed an activity of 21.7±2.45 ?mol/min/g. Conclusions. The values obtained coincide with those reported by laboratories accredited by the American Association of Veterinary Diagnostic Laboratories (AAVLD), confirming its ease to reproduce the technique and validating its use to support the diagnosis of intoxications by cholinesterase inhibitors.