title: Evaluation of the Test-mate ChE (cholinesterase) field kit in acute organophosphorus poisoning.
abstract: OBJECTIVE
  Measurement of acetylcholinesterase (AChE) is recommended in the management of organophosphorus poisoning, which results in 200,000 deaths worldwide annually. The Test-mate ChE 400 is a portable field kit designed for detecting occupational organophosphorus exposure that measures RBC AChE and plasma cholinesterase (PChE) within 4 minutes. We evaluate Test-mate against a reference laboratory test in patients with acute organophosphorus self-poisoning.
  
  
  METHODS
  This was a cross-sectional comparison study of 14 patients with acute organophosphorus poisoning between May 2007 and June 2008. RBC AChE and PChE were measured in 96 and 91 samples, respectively, with the Test-mate ChE field kit and compared with a reference laboratory, using the limits of agreement method (Bland and Altman), κ statistics, and Spearman's correlation coefficients.
  
  
  RESULTS
  There was good agreement between the Test-mate ChE and the reference laboratory for RBC AChE. The mean difference (Test-mate-reference) was -0.62 U/g hemoglobin, 95% limits of agreement -10.84 to 9.59 U/g hemoglobin. Good agreement was also observed between the categories of mild, moderate, and severe RBC AChE inhibition (weighted κ 0.85; 95% confidence interval [CI] 0.83 to 0.87). Measurement of PChE also showed good agreement, with a mean difference (Test-mate-reference) of +0.06 U/mL blood, 95% limits of agreement -0.41 to 0.53 U/mL blood. Spearman's correlation coefficients were 0.87 (95% CI 0.81 to 0.91) for RBC AChE and 0.76 (95% CI 0.66 to 0.84) for PChE. Analysis for within-subject correlation of subjects did not change the limits of agreement.
  
  
  CONCLUSIONS
  The Test-mate ChE field kit reliably provides rapid measurement of RBC AChE in acute organophosphorus poisoning.
authors.affiliation: South Asian Clinical Toxicology Research Collaboration, Peradeniya, Sri Lanka. bishan.rajapakse@gmail.com
authors.forename: Bishan N
authors.initials: BN
authors.lastname: Rajapakse
authors.forename: Horst
authors.initials: H
authors.lastname: Thiermann
authors.forename: Peter
authors.initials: P
authors.lastname: Eyer
authors.forename: Franz
authors.initials: F
authors.lastname: Worek
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Bowe
authors.forename: Andrew H
authors.initials: AH
authors.lastname: Dawson
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Buckley
mesh_terms: D000328:Adult; D002802:Cholinesterases / Q000097:blood*; D003430:Cross-Sectional Studies; D004912:Erythrocytes / Q000201:enzymology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D062025:Organophosphate Poisoning; D010575:Pesticides / Q000506:poisoning*; D011933:Reagent Kits, Diagnostic / Q000592:standards; D015203:Reproducibility of Results; D055815:Young Adult
chemical_list: D010575:Pesticides; D011933:Reagent Kits, Diagnostic; D002802:Cholinesterases