title: Unproven ingestion: an unrecognized bias in toxicological case series.
abstract: BACKGROUND
  Case series of ingestion in preschool children may include patients without significant exposure if the substance is not measured.
  
  
  METHODS
  In order to evaluate the unproven ingestion bias, we conducted, between January 2000 and June 2004, a retrospective analysis of a poison control center-based series of children <6 years old with a history of toxic methanol or ethylene glycol ingestion.
  
  
  RESULTS
  Over the 54 month period, 115 children were referred to obtain a level. Of these, 102 children, aged 25 +/- 10 months, actually had a level analyzed. Only 21 patients had positive levels measured a median of 90 minutes post-ingestion.
  
  
  CONCLUSIONS
  Our findings suggest that a significant fraction of purported cases were not confirmed. When a study aims at determining the toxicity of the substance, measurements of the xenobiotic should be required in any case series involving preschool aged children in order to decrease the unproven ingestion bias.
authors.affiliation: CHU Ste-Justine, Montreal, Quebec, Canada.
authors.forename: Arielle
authors.initials: A
authors.lastname: Lévy
authors.forename: Benoit
authors.initials: B
authors.lastname: Bailey
authors.forename: Anne
authors.initials: A
authors.lastname: Letarte
authors.forename: Claire
authors.initials: C
authors.lastname: Dupuis
authors.forename: Michel
authors.initials: M
authors.lastname: Lefebvre
mesh_terms: D015982:Bias; D002675:Child, Preschool; D019855:Ethylene Glycol / Q000506:poisoning*; D005260:Female; D006801:Humans; D007223:Infant; D008297:Male; D000432:Methanol / Q000506:poisoning*; D011039:Poison Control Centers / Q000706:statistics & numerical data*; D012189:Retrospective Studies
chemical_list: D019855:Ethylene Glycol; D000432:Methanol