Evaluation of the accuracy of “ChE check mobile” in measurement of acetylcholinesterase in pesticide poisoning

Background: Acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) are used in clinical management to confirm the diagnosis and indicate the severity of organophosphorus and carbamate poisoning. ChE check mobile is a new portable cholinesterase testing system developed in Germany. The study aims to evaluate the accuracy of ChE check mobile compared to the standard reference method and Test-mate ChE system.

Methods: Patients with organophosphorus and carbamate poisoning were recruited from two general hospitals in Sri Lanka between September 2013 and November 2014. The AChE was measured using the three methods.

Results: Blood samples were collected from 185 self-poisoned patients (170 organophosphorus and 15 carbamate) and 20 normal individuals. ChE check mobile correlated well with spectrophotometer readings (Pearson’s correlation coefficient 0.87) but gave higher values (Mean bias for AChE: +6.55 (95% CI: −11 to 24) U/g Hb). A similar positive bias from Test-mate results was also observed. Applying a correction factor derived from the volunteer samples (dividing by 1.353) greatly improved agreement in pesticide poisoned patients.

Conclusions: ChE check mobile system allowed for rapid determination of AChE activity but gave somewhat higher AChE compared to other methods. Applying a correction factor of 1.353 provide a good agreement to both reference and Test-mate ChE machine in this setting.