Evaluation of the performance of an handheld device for measuring cholinesterase activity, in order to use in cases of organophosphate poisoning

Cholinesterase activity monitoring during the organophosphorus pesticides poisoning is still a challenge in the remote areas. The objective of this study was to evaluate the performance of the Test-mate Model 400 EQM® for the determination of cholinesterase. This is a cross-sectional analytical study conducted with two different levels of quality control sera (QCs) and 40 sera of different cholinesterase concentrations from patients samples. The coefficient of variation obtained for repeatability was compared to the supplier's values. Spearman's coefficient and kappa coefficient (ĸ) were used to examine correlation and assess agreement between measurements obtained with the handheld device and the INDIKO analyzer, used as a reference test. For repeatability of EQM Test-mate ChE®, coefficients of variation was 5.5% and 6% for the normal and pathological control sera respectively, that is lower than 7.5% as recommended by the supplier. A Spearman correlation coefficient of r=0.7451 (p<0.0001) was obtained and a good agreement between the measurements ( ĸ=0.7253 (95%CI: 0.655- 0.841)). This handheld device is repeatable and showed a good correlation and agreement with the INDIKO® analyzer. It would therefore be suitable for determining cholinesterase activity in remote areas in case of organophosphate poisoning.