title: Biomarkers to disclose recent intake of alcohol: potential of 5-hydroxytryptophol glucuronide testing using new direct UPLC-tandem MS and ELISA methods.
abstract: OBJECTIVE
  This study compared two new methods for direct determination of 5-hydroxytryptophol glucuronide (GTOL) in urine, a biomarker for detection of recent alcohol consumption.
  
  
  METHODS
  Urine samples were collected from ten alcoholic patients during recovery from intoxication. A direct injection ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for measurement of the urinary GTOL to 5-hydroxyindoleacetic acid (5-HIAA) ratio, and an ELISA assay for direct measurement of GTOL, were used. Comparison was made with the urinary ethanol and ethyl glucuronide (EtG) concentrations.
  
  
  RESULTS
  The breath ethanol concentration on admission ranged between 1.0-3.1 g/l. The UPLC-MS/MS method showed a median detection time of 39 h for an elevated urinary GTOL/5-HIAA ratio, while EtG was detected for a median of 65 h. Determination of GTOL by the ELISA assay showed 87% sensitivity in detecting positive samples at a 44% specificity, as compared with the UPLC-MS/MS method.
  
  
  CONCLUSIONS
  The lower sensitivity of the urinary GTOL/5-HIAA ratio compared with EtG for recent drinking may be clinically useful, in cases where the EtG test provides an unwanted high sensitivity for intake of only small amounts of alcohol or unintentional ethanol exposure.
authors.affiliation: Department of Medicine, Karolinska Institute and Karolinska University Hospital, Stockholm, Sweden. olof.beck@karolinska.se
authors.forename: Olof
authors.initials: O
authors.lastname: Beck
authors.forename: Nikolai
authors.initials: N
authors.lastname: Stephanson
authors.forename: Michael
authors.initials: M
authors.lastname: Böttcher
authors.forename: Norbert
authors.initials: N
authors.lastname: Dahmen
authors.forename: Christoph
authors.initials: C
authors.lastname: Fehr
authors.forename: Anders
authors.initials: A
authors.lastname: Helander
mesh_terms: D000428:Alcohol Drinking / Q000652:urine*; D000437:Alcoholism / Q000652:urine; D015415:Biomarkers / Q000652:urine; D001944:Breath Tests; D002492:Central Nervous System Depressants / Q000652:urine; D002851:Chromatography, High Pressure Liquid; D004797:Enzyme-Linked Immunosorbent Assay; D000431:Ethanol / Q000652:urine; D020719:Glucuronides / Q000652:urine*; D006801:Humans; D006897:Hydroxyindoleacetic Acid / Q000652:urine; D006917:Hydroxytryptophol / Q000031:analogs & derivatives* / Q000652:urine; D021241:Spectrometry, Mass, Electrospray Ionization; D053719:Tandem Mass Spectrometry
chemical_list: C500750:5-hydroxytryptophol glucuronide; D015415:Biomarkers; D002492:Central Nervous System Depressants; D020719:Glucuronides; D006917:Hydroxytryptophol; D000431:Ethanol; D006897:Hydroxyindoleacetic Acid