title: Cross-reaction of propyl and butyl alcohol glucuronides with an ethyl glucuronide enzyme immunoassay.
abstract: BACKGROUND
  Ethyl glucuronide (EtG) in urine is considered a marker of recent alcohol consumption. Using immunoassays for EtG screening without confirmatory analysis bears a risk of getting false-positives as shown for trichloroethyl glucuronide from chloral hydrate medication and 1-propyl glucuronide from propanol-based hand disinfection. The aim of the study was to check whether glucuronides of frequently used aliphatic short chain alcohols aside from EtG and 1-propyl glucuronide can cross-react with the DRI(®) Ethyl Glucuronide Assay.
  
  
  METHODS
  Aliquots of EtG-free urine were individually spiked with methyl β-D-glucuronide, 1-propyl β-D-glucuronide, 2-propyl β-D-glucuronide, 1-butyl β-D-glucuronide, 2-butyl β-D-glucuronide, and tert-butyl β-D-glucuronide. To check the response rate of the DRI(®) Ethyl Glucuronide Assay to its target analyte, EtG was also added to a native EtG-free urine sample. The spiked alcohol glucuronide concentrations (seven levels up to 10mg/L) and the DRI(®) Ethyl Glucuronide Assay results were evaluated by Passing-Bablok regression analysis. The 95% confidence interval ranges for the slope of the regression function were considered a measure of cross-reaction of the individual alcohol glucuronides with the enzyme immunoassay.
  
  
  RESULTS
  2-Propyl glucuronide showed a cross-reactivity of 69-84% at the 95% probability level, methyl glucuronide, 1-propyl glucuronide, and 1- and 2-butyl glucuronide of 4-9%, and tert-butyl glucuronide almost no cross-reactivity. The response rate for EtG was 87-94% at the 95% probability level.
  
  
  CONCLUSIONS
  The DRI(®) Ethyl Glucuronide Assay shows cross-reaction rates with aliphatic short chain alcohol glucuronides aside from EtG which bear a risk of getting false-positives regarding ethanol consumption. Mass spectrometric detection of EtG is mandatory for confirmation of positive immunological EtG screenings.
authors.affiliation: Bioscientia Institut für Medizinische Diagnostik GmbH, Zentrum für Toxikologie und Forensik, Konrad-Adenauer-Straße 17, Ingelheim D-55218, Germany. Electronic address: torsten.arndt@bioscientia.de.
authors.forename: Torsten
authors.initials: T
authors.lastname: Arndt
authors.affiliation: Bioscientia Institut für Medizinische Diagnostik GmbH, Zentrum für Toxikologie und Forensik, Konrad-Adenauer-Straße 17, Ingelheim D-55218, Germany.
authors.forename: Reinhild
authors.initials: R
authors.lastname: Beyreiß
authors.affiliation: Bioscientia Institut für Medizinische Diagnostik GmbH, Zentrum für Toxikologie und Forensik, Konrad-Adenauer-Straße 17, Ingelheim D-55218, Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Schröfel
authors.affiliation: Bioscientia Institut für Medizinische Diagnostik GmbH, Zentrum für Toxikologie und Forensik, Konrad-Adenauer-Straße 17, Ingelheim D-55218, Germany.
authors.forename: Karsten
authors.initials: K
authors.lastname: Stemmerich
mesh_terms: D000428:Alcohol Drinking / Q000652:urine; D015415:Biomarkers / Q000652:urine; D053593:Forensic Toxicology; D005965:Glucuronates / Q000737:chemistry* / Q000652:urine; D020719:Glucuronides / Q000737:chemistry* / Q000652:urine; D006801:Humans; D007124:Immunoenzyme Techniques; D012044:Regression Analysis
chemical_list: D015415:Biomarkers; D005965:Glucuronates; D020719:Glucuronides; C093924:ethyl glucuronide
keywords: Abstinence; Alcohol marker; Butyl glucuronide; False-positives; Methyl glucuronide; Propyl glucuronide