title: Phosphatidylethanol: the potential role in further evaluating low positive urinary ethyl glucuronide and ethyl sulfate results.
abstract: BACKGROUND
  Whereas urinary ethyl glucuronide (EtG) levels above 1,000 ng/ml reflect with a high probability ethanol (EtOH) consumption, levels below this cutoff are difficult to interpret as both extraneous (nonbeverage) EtOH exposure, recent drinking, and more distant high EtOH intake (several days ago) might yield similar results. This might be of particular relevance in medico-legal cases. To overcome this dilemma, phosphatidylethanol (PEth) might be a promising marker, because blood PEth is only positive following significant alcohol use. The aim of our study was therefore to employ PEth as a marker to differentiate between the different conditions.
  
  
  METHODS
  Subjects included were 252 participants in monitoring with the Alabama Physician Health Program. All subjects testing positive for EtG and/or ethyl sulfate (EtS) who denied drinking after routine supportive confrontation were subject to information about PEth testing. If they still denied drinking, PEth testing was performed and the result communicated. EtG, EtS, and PEth testing was performed in a commercial laboratory using liquid chromatography tandem mass spectrometry methods.
  
  
  RESULTS
  Of a total of 18 subjects who tested positive for EtG and/or EtS, 10 denied drinking. Of the 7 who denied drinking after PEth explanation, in 5 cases, their claim was supported by a negative PEth result. In 2 cases, a positive PEth result was in contrast to their claim.
  
  
  CONCLUSIONS
  PEth results in combination with previous low positive EtG/EtS results allow differentiating between innocent/extraneous exposure and drinking. Negative PEth testing following low positive EtG/EtS results helps to further elucidate the findings and support the claim of the patient of recent alcohol abstinence. Positive PEth testing following positive EtG/EtS results confirms recent drinking.
authors.affiliation: Promises Treatment Centers , Los Angeles, California.
authors.forename: Gregory E
authors.initials: GE
authors.lastname: Skipper
authors.forename: Natasha
authors.initials: N
authors.lastname: Thon
authors.forename: Robert L
authors.initials: RL
authors.lastname: Dupont
authors.forename: Louis
authors.initials: L
authors.lastname: Baxter
authors.forename: Friedrich M
authors.initials: FM
authors.lastname: Wurst
mesh_terms: D000407:Alabama / Q000453:epidemiology; D000428:Alcohol Drinking / Q000097:blood* / Q000453:epidemiology / Q000652:urine*; D015415:Biomarkers / Q000097:blood / Q000652:urine; D005260:Female; D005965:Glucuronates / Q000097:blood / Q000652:urine*; D020404:Glycerophospholipids / Q000097:blood* / Q000652:urine; D006801:Humans; D008297:Male; D010865:Pilot Projects; D013463:Sulfuric Acid Esters / Q000097:blood / Q000652:urine*
chemical_list: D015415:Biomarkers; D005965:Glucuronates; D020404:Glycerophospholipids; D013463:Sulfuric Acid Esters; C051521:phosphatidylethanol; C093924:ethyl glucuronide; C011612:diethyl sulfate
keywords: Ethyl Glucuronide; Ethyl Sulfate; Monitoring; Phosphatidylethanol; Physician Health Program