Publications by authors named "Michel Yegles"

50 Publications

Phosphatidylethanol for Monitoring Alcohol Use in Liver Transplant Candidates: An Observational Study.

J Clin Med 2020 Sep 22;9(9). Epub 2020 Sep 22.

Psychiatric University Hospital, 4002 Basel, Switzerland.

Liver transplantation remains an essential procedure for many patients suffering from alcoholic liver disease. Alcohol use monitoring remains paramount all through the stages of this complex process. Direct alcohol biomarkers, with improved specificity and sensibility, should replace traditional indirect markers. Phosphatidylethanol (PEth) has been recently tested in alcoholic liver disease patients, but more evidence is needed, especially in comparison with other direct biomarkers. We conducted an observational study among patients awaiting liver transplantation. We analyzed Peth in blood, ethylglucuronide (EtG) in hair and urine and ethylsulphate (EtS) in urine, using mass spectrometry methods. In addition, transaminases, and self-reports were analyzed. A total of 50 patients were included (84% men, mean age 59 years (SD = 6)). 18 patients (36%) screened positive for any marker. Self-reports were positive in 3 patients. EtS was the biomarker with more positive screens. It also was the most frequently exclusive biomarker, screening positive in 7 patients who were negative for all other biomarkers. PEth was positive in 5 patients, being the only positive biomarker in 2 patients. It showed a false negative in a patient admitting alcohol use the previous week and screening positive for EtG and EtS. Hair EtG was positive in 3 patients who had negative Peth, EtG. EtG did not provide any exclusive positive result.A combination of biomarkers seems to be the best option to fully ascertain abstinence in this population. Our study suggest EtS might also play a significant role.
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http://dx.doi.org/10.3390/jcm9093060DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7564451PMC
September 2020

AEME production in cocaine positive hair after thermal hair treatment.

Forensic Sci Int 2019 Sep 26;302:109894. Epub 2019 Jul 26.

Service de Toxicologie Médico-légale, Laboratoire National de Santé, Dudelange, Luxembourg.

Introduction: Currently, hair straightening has become a regular hair treatment for women but likewise for men. Several studies have shown that thermal straightening has an influence on the concentration of ethyl glucuronide and of drugs of abuse content in hair. Heat treatment of hair may decrease concentrations of cocaine (COC) and of cocaethylene (CE) in hair and increase concentrations of benzoylecgonine (BZE). The goal of this study was to evaluate the influence of thermal straightening on anhydroecgonine methyl ester (AEME), a known cocaine smoking marker, in hair.

Method: 42 positive COC hair samples were treated in vitro with iron plates heated to 200°C. During this treatment one lock of hair was put sequentially 30 times in contact with a hair straightener during 2s, the other lock was not treated. The hair samples were analyzed by a validated GC/MS method for AEME, COC and its metabolites BZE, norcocaine (NC), ecgonine methyl ester (EME) and CE.

Results: After treatment, a median increase of concentrations was observed for AEME (110.3%) and BZE (27.6%) whereas a median decrease was found for COC (56.9%), NC (46.7%), EME (33.3%) and CE (41.7%). The median BZE/COC ratio of 0.6 in not treated hair increased to 1.5 in treated hair.

Conclusion: Regarding our in vitro results, AEME may be produced by thermal hair straightening. Therefore, the presence of AEME in hair should not be used as an irrefutable prove of cocaine smoking. Our study shows that for the interpretation of AEME results in hair, potential heat treatment of hair should be considered. A ratio BZE/COC higher 1 appears to be a good marker to identify thermal treatment of hair before collection. Finally, thermal straightening should be documented during hair collection and should also be considered for the interpretation of COC results in hair.
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http://dx.doi.org/10.1016/j.forsciint.2019.109894DOI Listing
September 2019

Influence of cosmetic hair treatments on cannabinoids in hair: Bleaching, perming and permanent coloring.

Forensic Sci Int 2019 Apr 26;297:270-276. Epub 2019 Feb 26.

Laboratoire National de Santé, Service de Toxicologie, medico-légale, Dudelange, Luxembourg.

Various cosmetic hair manipulations are known to interfere with drug of abuse concentrations in hair. It is important to evaluate the effects of cosmetic hair treatments as they can influence quantitative hair results. Only one study showed a significant decrease of THC after bleaching and coloring. The aim of the study was to investigate the effect of bleaching, perming and dyeing treatment on d-9-tetrahydrocannabinol (THC), but also Cannabidiol (CBD), Cannabinol (CBN) and 11-nor-D9-tetrahydrocannabinol-9-carboxylic acid (THC-COOH) in hair. Thirty THC-positive hair samples were selected in this study. A single hair lock was divided in 2 separate locks and the proximal 3 cm segment was analyzed. One lock served as control while the other lock was bleached, permed or dyed respectively. Hair was analyzed using a routine method including cleaning, treatment of hair with NaOH and 2 different SPE extractions for THC, CBN, CBD and THC-COOH respectively. Analysis was performed with routine methods using GC/MS-MS in electron impact (EI) mode for THC, CBN and CBD or negative chemical ionization (NCI) mode for THC-COOH after PTV-injection. Bleaching and perming reduced all cannabinoids concentration in hair; THC was more affected than THC-COOH, CBN and CBD. Bleaching caused strong chemical degradation on cannabinoids, while perming exerted more a leaching out effect. Permanent colorings in single applications had only little effects on cannabinoids. Finally this study highlights the importance of considering bleaching and perming for the correct interpretation of hair results.
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http://dx.doi.org/10.1016/j.forsciint.2019.02.030DOI Listing
April 2019

How to Interpret Hair EtG Concentrations in Individuals with High Body Mass Index? Brief Commentary on: Influence of Body Mass Index on Hair Ethyl Glucuronide Concentrations.

Alcohol Alcohol 2019 Mar;54(2):188-189

Toxicological Center, Antwerp University, Antwerp, Belgium.

Body mass index (BMI) is a variable that complicates the interpretation of the alcohol metabolite ethyl glucuronide (EtG) in hair. However, direction on how EtG should currently be interpreted within individuals consuming moderate and excessive daily amounts of alcohol related to their BMI is lacking. In light of interpretation of EtG in individuals with high BMI, we present post hoc analysis of earlier data regarding the effect of BMI on hair EtG concentrations.
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http://dx.doi.org/10.1093/alcalc/agz006DOI Listing
March 2019

Determination of cannabinoids in hair of CBD rich extracts consumers using gas chromatography with tandem mass spectrometry (GC/MS-MS).

Forensic Sci Int 2018 Nov 6;292:163-166. Epub 2018 Oct 6.

Laboratoire national de santé, L-3555 Dudelange, Luxembourg. Electronic address:

Medical cannabis is becoming increasingly popular for many different ailments and improvement of general well-being. Particularly CBD-rich extracts are easily available via online pharmacies, health stores or directly from producers. However, almost all of the extracts contain small amounts of THC. Thus, in case of continuous or heavy use of CBD rich cannabis, THC concentrations in hair may rise above accepted legal limits. In our study, we investigated THC, CBN and CBD in hair samples from regular CBD rich cannabis users. The goals were to determine levels of the cannabinoids in hair and to evaluate a possible correlation between regular CBD intake and CBD levels in hair. All participants consumed cannabis extracts from the same producer. It contained CBD at different concentrations and small amounts of THC with a CBD/THC concentration ratio of 30. The self-declared CBD dosage ranged from 4 to 128mg CBD/day, corresponding to a daily THC intake of 0.1 to 4.3mg. After extraction and derivatization, hair samples were analysed using a validated GC/MS-MS method. CBD concentrations ranged from 10 to 325pg/mg of hair, but no significant correlation was observed between CBD concentrations and the daily dose. THC was detected in one sample only at a concentration below our cut-off, whereas CBN was not detected. In this study, we showed that even after repeated consumption of CBD-rich cannabis extracts in medium to high doses, consumers are generally tested negative for THC in hair.
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http://dx.doi.org/10.1016/j.forsciint.2018.09.015DOI Listing
November 2018

Gammahydroxybutyrate in hair of non-GHB and repeated GHB users: A new and optimized method.

Forensic Sci Int 2018 Oct 30;291:193-198. Epub 2018 Aug 30.

Laboratoire National de Santé, Service de Toxicologie, Dudelange, Luxembourg.

Gamma-hydroxybutyric acid (GHB) is a short-chain fatty acid used recreationally as a drug of abuse due its strong suppressive effect on the central nervous system. The detection window of GHB in blood and urine is very narrow (t1/2=30min) but can be substantially prolonged using alternative matrices such as hair. We here present a newly developed and limited validated method with a solid phase extraction (SPE) using GC-MS/MS to determine concentrations of GHB in hair samples. The soft extraction technique (water and 90min ultrasonic bath) preserves GHB with a high yield and clean extracts. In addition, endogenous GHB can be detected in hair of non-GHB users. However, little is known about GHB concentrations in hair of abstinent, frequent and chronic GHB users. Therefore, we present data from hair samples of healthy volunteers to evaluate the proposed endogenous GHB ranges, and from GHB-dependent patients to address GHB concentrations in hair with GHB intake. In 20 non-GHB users, a mean endogenous concentration of 1.1±0.6ng/mg hair (range of 0.3-2ng/mg) was found. In GHB-dependent patients, concentrations between 6.3-239.6ng/mg hair were found, with no correlation between concentrations in hair and dose of GHB intake. In summary, we present a new and limited validated method, adequately sensitive for the detection of GHB in hair, as well as first-time measurements of GHB concentrations in dependent patients in order to better understand the relationship between the frequency of use/dose and concentrations observed in hair samples.
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http://dx.doi.org/10.1016/j.forsciint.2018.08.025DOI Listing
October 2018

Screening for Hazardous Drinking in Nursing Home Residents: Evaluating the Validity of the Current Cutoffs of the Alcohol Use Disorder Identification Test-Consumption Questions by Using Ethyl Glucuronide in Hair.

Alcohol Clin Exp Res 2017 Sep 14;41(9):1593-1601. Epub 2017 Aug 14.

Paracelsus Medical University, Salzburg, Austria.

Background: Because of physiological changes, elderly people are much more exposed to the adverse effects of alcohol. Therefore, hazardous drinking is defined at lower levels as compared to younger adults. This work aimed to evaluate the validity of the current cutoff levels of the Alcohol Use Disorder Identification Test-Consumption (AUDIT-C) questions to detect hazardous drinking in the elderly by using ethyl glucuronide in hair (HEtG).

Methods: In a border region between Austria and Germany, 344 nursing home residents were included from 33 of the 107 nursing homes. Residents were asked to answer the AUDIT-C questions, hair samples were obtained, and nursing staff members were asked for their assessments of the residents' alcohol consumption. Hair samples were analyzed for HEtG using gas chromatography-mass spectrometry. Receiver-operating characteristic (ROC) curve analysis was performed to determine the validity of cutoff values for the AUDIT-C to detect an alcohol consumption of ≥10 g of alcohol/d.

Results: A total of 11.3% of the nursing home residents (n = 344) drank ≥10 g of alcohol/d (4.9% >60 g of alcohol/d, 6.4% 10 to 60 g of alcohol/d, 88.7% <10 g of alcohol/d)). For the drinking limit of ≥10 g of alcohol/d, ROC curve analysis showed a balanced sensitivity and specificity, with an AUDIT-C cutoff of ≥4 for men (sensitivity: 70%, specificity: 83.6%; AUC = 0.823, CI = 0.718 to 0.928, p < 0.001) and ≥2 for women (sensitivity: 73.7%, specificity: 81.9%; AUC = 0.783, CI = 0.653 to 0.914, p < 0.001). Nursing staff (n = 274) underestimated alcohol consumption and evaluated 40% of the chronic-excessive alcohol consumers (>60 g of alcohol/d) as being abstinent.

Conclusions: Our data suggest that an AUDIT-C cutoff of ≥4 for men and ≥2 for women can be recommended to detect the consumption of ≥10 g of alcohol/d in the elderly. Because the nursing staff to a large extent underestimates the alcohol consumption among nursing home residents, further teaching of the staff, improvement of screening instruments for the elderly, and the use of objective biomarkers might be helpful for recognizing hazardous drinking and can thus help improve the quality of life of the elderly.
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http://dx.doi.org/10.1111/acer.13449DOI Listing
September 2017

Hair ethyl glucuronide concentrations in teetotalers: Should we re-evaluate the lower cut-off?

Forensic Sci Int 2017 May 14;274:107-108. Epub 2016 Nov 14.

Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Wilrijk, Belgium; Toxicology and TDM Laboratory, ZNA Stuivenberg, Antwerp, Belgium.

Aims: Ethyl glucuronide in hair (hEtG) can be used to assess the retrospective consumption of alcohol. A lower cut-off of 7pg/mg hair in the 0-3cm proximal scalp hair segment has been used for repeated alcohol consumption in the previous three months. While a concentration below this cut-off is stated not to contradict self reported abstinence, it is often used to assess whether an individual has remained abstinent in the period prior to hair sampling. Here, we address hEtG concentrations in alcohol consuming individuals and critically evaluate this cut-off value.

Methods: Ten individuals remained abstinent from alcohol for 12 weeks. A lock of hair was cut before the start of the study, and the regrown hairs were cut after twelve weeks of abstinence. Hair EtG concentrations were measured both at baseline and after 12 weeks of abstinence. Study compliance was assessed by urine analysis every 2-3 days by liquid chromatography-tandem mass spectrometry with a lower limit of quantification (LLOQ) of 0.1μg/mL. HEtG concentrations were assessed in the first 3cm hair using gas chromatography-tandem mass spectrometry with an LLOQ of 0.2pg/mg.

Results: At the beginning of the study, participants had hEtG concentrations ranging between
Discussion: In participants consuming no alcohol, all but one had low, but measurable hEtG concentrations (up to 4.5pg/mg hair), which was in the participant with the highest pre-study alcohol consumption. As only regrown hairs were cut, it is not likely that this was due to residual EtG from the pre-study period.

Conclusions: Although the number of specimens was low, this study reports measurable hEtG concentrations following total abstinence, although not exceeding the current 7pg/mg cut-off for hair. A suitable sensitive method (GC-MS/MS) is preferred when assessing alcohol abstinence. We propose that the current cut-off of 7pg/mg should be discussed further, and, in view of the small study sample, evaluated using a larger sample size.
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http://dx.doi.org/10.1016/j.forsciint.2016.11.008DOI Listing
May 2017

Influence of Body Mass Index on Hair Ethyl Glucuronide Concentrations.

Alcohol Alcohol 2017 Jan 20;52(1):19-23. Epub 2016 Oct 20.

Laboratoire National de Santé, Service de Toxicologie, Dudelange, Luxembourg.

Aim: Analysis of ethyl glucuronide (EtG) concentrations in hair is increasingly used to estimate the consumption of alcohol of the prior months. Linear correlations between the amount of alcohol consumed and the concentration of EtG in hair have been reported, and several variables that may influence this correlation have been investigated: e.g. cosmetic hair treatments, gender influences or hair color. Here, we investigate the influence of body mass index (BMI) on this correlation.

Methods: A post hoc analysis on the influence of BMI on the relation between amounts of alcohol consumed and the measured EtG concentrations in hair in 199 participants.

Results: Our data show higher EtG concentrations in participants with high BMI (≥25) compared to participants with low BMI (<25) (P = 0.001) across a wide range of amounts of alcohol consumed.

Conclusions: We conclude that BMI should be taken into account when interpreting hair EtG concentrations.

Short Summary: Ethyl glucuronide concentrations in hair (hEtG) can be used to estimate the consumption of alcohol of the prior months. Body mass index (BMI) influences this relation and BMI should be taken into account when interpreting hEtG concentrations in participants with high BMI (≥25) compared to participants with low BMI (<25).
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http://dx.doi.org/10.1093/alcalc/agw079DOI Listing
January 2017

Biomarkers for detection of alcohol consumption in liver transplantation.

World J Gastroenterol 2016 Apr;22(14):3725-34

Katharina Staufer, Division of Transplantation, Department of Surgery, Medical University of Vienna, 1090 Vienna, Austria.

Alcoholic liver disease is an established, yet controversial, indication for liver transplantation. Although an abstinence period of up to 6 mo prior to transplantation is mandatory, alcohol relapse after transplantation is a common event. In case of recurrence of heavy drinking, graft survival is significantly impaired. Guidelines on detection and surveillance of alcohol consumption in this patient cohort are lacking. This review summarizes the challenge of patient selection as well as the current knowledge on established and novel alcohol biomarkers with special focus on liver transplant candidates and recipients.
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http://dx.doi.org/10.3748/wjg.v22.i14.3725DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4814735PMC
April 2016

Hair ethyl glucuronide and serum carbohydrate deficient transferrin for the assessment of relapse in alcohol-dependent patients.

Clin Biochem 2016 May 3;49(7-8):554-9. Epub 2016 Feb 3.

Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium; Toxicology and TDM Laboratory, ZNA Stuivenberg Hospital, Antwerp, Belgium.

Objectives: Ethyl glucuronide in hair (hEtG) and serum carbohydrate deficient transferrin (%CDT) are valuable markers for alcohol abuse, but their diagnostic accuracy to monitor abstinence and relapse is unclear. Here, we investigate to what extent repeated measurements of hEtG and %CDT can be used to monitor relapse in alcohol-dependent patients during abstinence treatment.

Design And Methods: HEtG and %CDT were measured in individuals starting treatment for alcohol dependence both at treatment entry and 3months later. Alcohol consumption and relapse episodes were recorded using the Time Line Follow Back and by alcohol breath and urine tests, and correlated with hEtG and %CDT measurements.

Results: Fifteen patients completed the study, of which nine had one or more relapses. Hair EtG and serum %CDT identified whether a relapse occurred in 78% and 57% of cases, respectively. Only hEtG correlated with the amount of alcohol consumed before treatment entry (Pearson r=0.92; p<0.001). The specificity of %CDT to assess abstinence during treatment was 100%. HEtG had a specificity of only 17%; however, in all patients who remained abstinent, hEtG decreased with >85% from initial values. Mean hEtG, but not %CDT, differed significantly between patients who relapsed and patients who remained abstinent (p=0.034).

Conclusions: HEtG was more sensitive than serum %CDT to assess relapse in alcohol-dependent patients and was positively correlated with the amounts of alcohol consumed. In contrast, serum %CDT was more specific for assessing abstinence. We highlight the benefit of repeated measurements of hEtG and serum %CDT for monitoring abstinence during treatment.
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http://dx.doi.org/10.1016/j.clinbiochem.2015.11.023DOI Listing
May 2016

Influence of thermal hair straightening on cannabis and cocaine content in hair.

Forensic Sci Int 2016 Aug 7;265:13-6. Epub 2016 Jan 7.

Laboratoire National de Santé, Forensic Toxicology, 1, rue Louis Rech, L-3555 Dudelange Luxembourg. Electronic address:

It has been shown that cosmetic treatment like bleaching and perming may lead to an important decrease of drugs of abuse content in hair. Currently, hair straightening has become a regular hair treatment especially for women. The aim of this preliminary study was to investigate the effect of in vitro treatment of hair with heat straightener on cannabis and cocaine concentrations in hair. 17 positive cannabis and 7 positive cocaine hair samples were treated in vitro with a hair straightener. During this treatment hair was put sequentially 30 times in contact with heated iron plates at 200°C during 2s corresponding to a total time of contact of 1min. THC and Cannabinol (CBN) were analysed in cannabis positive hair and cocaine, benzoylecgonin (BZE) and cocaethylene were analysed in cocaine positive hair. Analyses were performed with routine methods using GC/MS in electron impact mode. Regarding cannabis results a decrease of THC concentrations was found in 11 of 17 hair samples after thermal treatment, whereas in 6 cases an increase was shown. In all the hair samples CBN concentrations was explicitly higher after the in vitro treatment. Regarding cocaine results cocaine and cocaethylene concentrations decreased after treatment in all seven hair samples; in contrast, higher concentrations of BZE were determined. The strong increase of CBN and BZE content in hair after thermal treatments may be due to the fact that THC is converted by heat into CBN and cocaine into BZE, thus changing the respective ratios of the analysed substances. In conclusion, thermal straightening should be considered as other cosmetic hair treatments for a correct interpretation of hair results.
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http://dx.doi.org/10.1016/j.forsciint.2016.01.002DOI Listing
August 2016

Ethyl glucuronide concentrations in hair: a controlled alcohol-dosing study in healthy volunteers.

Anal Bioanal Chem 2016 Mar 9;408(8):2019-25. Epub 2015 Nov 9.

Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Campus Drie Eiken, Universiteitsplein 1, 2610, Antwerp, Wilrijk, Belgium.

Ethyl glucuronide (EtG) is a minor phase II metabolite of alcohol that accumulates in hair. It has been established as a sensitive marker to assess the retrospective consumption of alcohol over recent months using a cut-off of ≥7 pg/mg hair to assess repeated alcohol consumption. The primary aim was to assess whether amounts of alcohol consumed correlated with EtG concentrations in hair. Additionally, we investigated whether the current applied cut-off value of 7 pg/mg hair was adequate to assess the regular consumption of low-to-moderate amounts of alcohol. A prospective controlled alcohol-dosing study in 30 healthy individuals matched on age and gender. Individuals were instructed to drink no alcohol (N = 10), 100 g alcohol per week (N = 10) or 150 g alcohol per week (N = 10) for 12 consecutive weeks, before and after which hair was collected. Throughout the study, compliance to daily alcohol consumption was assessed by analyzing urine EtG three times weekly. Participants in the non-drinking group had median EtG concentrations of 0.5 pg/mg hair (interquartile range (IQR) 1.7 pg/mg; range < 0.21-4.5 pg/mg). Participants consuming 100 and 150 g alcohol per week showed median EtG concentrations of 5.6 pg/mg hair (IQR 4.7 pg/mg; range 2.0-9.8 pg/mg) and 11.3 pg/mg hair (IQR 5.0 pg/mg; range 7.7-38.9 pg/mg), respectively. Hair EtG concentrations between the three study groups differed significantly from one another (p < 0.001). Hair EtG concentrations can be used to differentiate between repeated (low-to-moderate) amounts of alcohol consumed over a long time period. For the assessment of repeated alcohol use, we propose that the current cut-off of 7 pg/mg could be re-evaluated.
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http://dx.doi.org/10.1007/s00216-015-9117-0DOI Listing
March 2016

Ethanol metabolites: their role in the assessment of alcohol intake.

Alcohol Clin Exp Res 2015 Nov 7;39(11):2060-72. Epub 2015 Sep 7.

Institute of Forensic Medicine, University of Bern, Bern, Switzerland.

Background: Alcohol-related disorders are common, expensive in their course, and often underdiagnosed. To facilitate early diagnosis and therapy of alcohol-related disorders and to prevent later complications, questionnaires and biomarkers are useful.

Methods: Indirect state markers like gamma-glutamyl-transpeptidase, mean corpuscular volume, and carbohydrate deficient transferrin are influenced by age, gender, various substances, and nonalcohol-related illnesses, and do not cover the entire timeline for alcohol consumption. Ethanol (EtOH) metabolites, such as ethyl glucuronide, ethyl sulfate, phosphatidylethanol, and fatty acid ethyl esters have gained enormous interest in the last decades as they are detectable after EtOH intake.

Results: For each biomarker, pharmacological characteristics, detection methods in different body tissues, sensitivity/specificity values, cutoff values, time frames of detection, and general limitations are presented. Another focus of the review is the use of the markers in special clinical and forensic samples.

Conclusions: Depending on the biological material used for analysis, ethanol metabolites can be applied in different settings such as assessment of alcohol intake, screening, prevention, diagnosis, and therapy of alcohol use disorders.
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http://dx.doi.org/10.1111/acer.12851DOI Listing
November 2015

Letter to the Editor Regarding 'A Comparison Between Serum Carbohydrate-Deficient Transferrin and Hair Ethyl Glucuronide in Detecting Chronic Alcohol Consumption in Routine'.

Alcohol Alcohol 2015 Jul 28;50(4):485-6. Epub 2015 May 28.

Toxicological Center, University of Antwerp, Antwerp, Belgium Toxicology and TDM Laboratory, ZNA Stuivenberg, Antwerp, Belgium.

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http://dx.doi.org/10.1093/alcalc/agv054DOI Listing
July 2015

Gas chromatographic determination of ethyl glucuronide in hair: comparison between tandem mass spectrometry and single quadrupole mass spectrometry.

Forensic Sci Int 2015 Apr 23;249:20-4. Epub 2014 Dec 23.

Toxicological University of Antwerp, Universiteitsplein 1, B2610 Antwerp, Belgium.

Ethyl glucuronide (EtG), a minor metabolite of ethanol, accumulates in hair and is currently used as a long-term marker for the detection of chronic and excessive alcohol consumption. Sensitive methods are required to differentiate teetotalers from moderate drinkers according to the established cut-off (i.e., 7 pg/mg hair). The aim of this study was to develop a sensitive method using gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) operated in the negative ion chemical ionization (NICI) mode. The validated method was applied to hair samples from teetotalers, moderate and excessive alcohol consumers, and results were compared to a previously validated GC-NICI-MS method. The developed GC-NICI-MS/MS method showed linearity over a range from 2 to 400 pg/mg hair, with a limit of detection (LOD) of 0.05 pg/mg hair and a lower limit of quantification (LLOQ) of 0.2 pg/mg hair, compared to an LOD of 0.5 pg/mg hair and LLOQ of 1.5 pg/mg hair obtained with GC-NICI-MS. Furthermore, lower background noise was observed using GC-NICI-MS/MS. Comparison of results of hair samples (n=58) obtained by GC-NICI-MS and GC-NICI-MS/MS showed no significant difference between both methods (paired-sample t-test, p>0.05; mean CV=1.0%). The differences between both methods were larger for EtG concentrations<30 mg/pg hair (mean CV=1.7%) than for EtG concentrations>30 mg/pg hair (mean CV=0.7%). This suggests a higher selectivity of GC-NICI-MS/MS at lower concentrations. In conclusion, by using GC-NICI-MS/MS, a higher analytical selectivity and an improved signal to noise ratio, can be achieved. Although GC-NICI-MS would not change the interpretation of the EtG concentrations, the present GC-NICI-MS/MS method should preferentially be used for the determination of EtG in hair, especially when differentiating between teetotalers and moderate drinkers according to the current cut-off (i.e., 7 pg/mg hair).
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http://dx.doi.org/10.1016/j.forsciint.2014.11.022DOI Listing
April 2015

Influence of repeated permanent coloring and bleaching on ethyl glucuronide concentrations in hair from alcohol-dependent patients.

Forensic Sci Int 2015 Feb 9;247:18-22. Epub 2014 Dec 9.

Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Antwerp, Belgium; Toxicology Laboratory, ZNA Stuivenberg, Antwerp, Belgium.

Background: Ethyl glucuronide (EtG), a minor metabolite of alcohol, is used as a sensitive marker in hair to detect the retrospective consumption of alcohol. The proximal 0-3 cm hair segment is often used for analysis, providing information on alcohol consumption over the past 3 months. Using more distal segments would allow the detection of alcohol consumption over longer time periods, thereby addressing the chronicity of the consumption. In view of this, permanent coloring and bleaching were shown in vitro to alter EtG concentrations in hair, but no in vivo studies are available to prove or disprove this.

Aims: To investigate the influence of repeated bleaching and permanent coloring on EtG concentrations in vivo and to assess the stability of EtG concentrations in distal compared to proximal hair segments.

Methods: Hair samples from alcohol-dependent patients with uncolored/unbleached (N=4), permanent coloration (N=5) and bleached hair (N=5) were analyzed in two to six 3 cm long segments for EtG concentrations, and alcohol consumption and hair cosmetic treatments were assessed.

Results: We observed that hair bleaching and permanent coloring reduces EtG concentrations by 82±11% and 65±24%, respectively, with correlations between the number of cosmetic treatments and the decrease in EtG concentrations. EtG remained stable in untreated hair samples up to 18 cm.

Conclusions: EtG is a sensitive marker to assess chronic alcohol consumption up to 18 months in alcohol-dependent patients with no cosmetic hair treatments. However, in alcohol-dependent patients who color or bleach their hair, care should be taken when interpreting EtG measurements.
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http://dx.doi.org/10.1016/j.forsciint.2014.11.023DOI Listing
February 2015

Impact of the grinding process on the quantification of ethyl glucuronide in hair using a validated UPLC-ESI-MS-MS method.

J Anal Toxicol 2015 Jan-Feb;39(1):17-23. Epub 2014 Oct 1.

Federal Public Service Justice, National Institute of Criminalistics and Criminology, Brussels, Belgium.

The Society of Hair Testing (SoHT) has provided cutoffs for the quantification of ethyl glucuronide (EtG) in hair to indicate occasional or chronic/excessive alcohol consumption. Although several sensitive methods have been reported, past proficiency test results show a lack of reproducibility. An ultra-performance liquid chromatographic mass spectrometric method (LLOQ of 10 pg EtG/mg hair) has been validated according to the international guidelines, including the successful participation in five proficiency tests. This method was subsequently used to evaluate the impact of different grinding conditions (cut, weakly or extensively pulverized hair samples) on the final measured EtG concentration. Hair from alcohol consumers (n = 2) and commercially available quality control samples (QCs) (n = 2) was used. For the QCs, extensive pulverization led to a significantly higher amount of measured EtG. In the hair samples obtained from volunteers, cut or weakly pulverized hair resulted in EtG concentrations below the LLOQ, while the mean concentrations of 14 and 40 pg EtG/mg hair were determined after extensive pulverization. Differences in sample preparation could partially explain inter-laboratory variability. As the differences in results can lead to a different interpretation even when applying the SoHT cutoffs, it is of interest to standardize sample preparation techniques in the field of EtG hair testing.
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http://dx.doi.org/10.1093/jat/bku108DOI Listing
October 2015

Time resolved analysis of quetiapine and 7-OH-quetiapine in hair using LC/MS-MS.

Forensic Sci Int 2014 Sep 11;242:200-203. Epub 2014 Jul 11.

Toxicological Center, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, 2610 Antwerp, Belgium. Electronic address:

Hair analysis is a powerful tool for retrospective drug analysis and has a wide application window. This article describes the simultaneous determination and quantification of the short-acting atypical antipsychotic drug quetiapine and its main metabolite 7-OH quetiapine in hair. A sensitive and accurate method for the determination of these two compounds was developed using high-performance liquid chromatography coupled to tandem mass spectrometry detection (LC-MS/MS). The method was applied to 10 real case samples. For five patients, a time resolved hair analysis was done. Results varied from 0.35 ng/mg to 10.21 ng/mg hair for quetiapine and from 0.02 ng/mg to 3.19 ng/mg hair for 7-OH-quetiapine.
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http://dx.doi.org/10.1016/j.forsciint.2014.07.002DOI Listing
September 2014

Hair ethyl glucuronide as a biomarker of alcohol consumption in alcohol-dependent patients: role of gender differences.

Drug Alcohol Depend 2014 Aug 2;141:163-6. Epub 2014 Jun 2.

Toxicological Center, University of Antwerp, Universiteitsplein 1, B2610 Antwerp, Belgium; Toxicology Laboratory, ZNA Stuivenberg, Lange Beeldekenstraat 267, B2060 Antwerp, Belgium. Electronic address:

Background: Ethyl glucuronide (EtG) is a minor alcohol metabolite that accumulates in hair and is proposed as a stable marker for the detection of chronic and excessive alcohol consumption above a cut-off level of 30pg/mg hair. A correlation between drinking behavior and EtG hair concentrations is observed, but large variability exists.

Aims: To investigate the correlation between alcohol consumption and hair EtG concentrations in alcohol dependent patients, and the effect of gender differences as a factor for the variability on this correlation.

Methods: EtG was measured by gas chromatography coupled to mass spectrometry in the hairs (first 3cm) of 36 alcohol dependent patients (25 males/11 females) starting and alcohol detoxification program. Factors that possibly influence EtG content in hair (except age and gender) were excluded. Detailed retrospective alcohol consumption was obtained over the last 3 months using the Timeline Follow Back interview.

Results: Median total alcohol consumption over 3 months was 13,050g pure alcohol (range 60-650g/day). Hair EtG concentrations varied between 32 and 662pg/mg. There was a statistically significant linear and positive correlation between hair EtG and amounts of alcohol consumed (Pearson r=0.83; p<0.001), in both males (Pearson r=0.83; p<0.001) and females (Pearson r=0.76; p=0.007).

Conclusions: There is a linear correlation, with no significant effect of gender, between hair EtG concentrations and amounts of alcohol consumed in alcohol-dependent individuals. Analysis of EtG in hair can be applied to estimate retrospective alcohol consumption in both male and female alcohol dependent subjects using the same cut-off.
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http://dx.doi.org/10.1016/j.drugalcdep.2014.05.014DOI Listing
August 2014

Influence of thermal hair straightening on ethyl glucuronide content in hair.

Drug Test Anal 2014 Jun;6 Suppl 1:74-7

Laboratoire National de Santé, Division de Toxicology, L-1511, Luxembourg.

Hair analysis of ethyl glucuronide (EtG) has become a valuable marker for the detection of moderate and chronic alcohol consumption. It has been shown that bleaching and perming may decrease EtG content in hair. So far, no studies exist about the influence of thermal hair straightening on EtG content in hair. Forty-one positive EtG hair samples were treated in vitro with a hair straightener at 200°C. Duration of treatment of 1 min was chosen for this study. After washing, pulverization, incubation in ultrasonic bath, solid-phase extraction, and derivatization with heptafluorobutyric anhydride, EtG was determined by gas chromatography-mass spectrometry - negative ion chemical ionization (GC-MS-NICI). The EtG contents in straightened hair strands were then compared with those in the corresponding untreated strands. In 20 of 41 hair samples, a decrease of EtG content was found ranging from 0.7% to 79.3% (average 20%) whereas in 21 cases an increase was shown ranging from 2.0% to 50.9% (average 15%). The variation of the results seems to depend on hair colour. The decrease may be explained by thermic in vitro destruction of EtG. The increase may be explained by denaturation of the hair matrix by thermal treatment possibly causing a better extraction of EtG during incubation in ultrasonic bath. This in vitro study indicates that thermal hair straightening has an impact on the EtG content in hair. This has to be considered for a correct interpretation of EtG results in hair. However, these results should be confirmed by in vivo studies.
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http://dx.doi.org/10.1002/dta.1648DOI Listing
June 2014

Ethylglucuronide in hair is a top predictor of impaired driving recidivism, alcohol dependence, and a key marker of the highest BAC interlock tests.

Traffic Inj Prev 2014 ;15(4):361-9

a Pacific Institute for Research and Evaluation , Calverton , Maryland.

Objectives: This study focuses on the predictive and comparative significance of ethyl glucuronide measured in head hair (hEtG) for estimating risks associated with alcohol-impaired driving offenders. Earlier work compared different alcohol biomarkers for estimating rates of failed blood alcohol concentration (BAC) tests logged during 8 months of interlock participation. These analyses evaluate the comparative performance of several alcohol markers including hEtG and other markers, past driver records, and psychometric assessment predictors for the detection of 4 criteria: new driving under the influence (DUI) recidivism, alcohol dependence, and interlock record variables including fail rates and maximal interlock BACs logged.

Methods: Drivers charged with alcohol impairment (DUI) in Alberta, Canada (n = 534; 64% first offenders, 36% multiple offenders) installed ignition interlock devices and consented to participate in research to evaluate blood-, hair-, and urine-derived alcohol biomarkers; sit for interviews; take psychometric assessments; and permit analyses of driving records and interlock log files. Subject variables included demographics, alcohol dependence at program entry, preprogram prior DUI convictions, postenrollment new DUI convictions, self-reported drinking assessments, morning and overall rates of failed interlock BAC tests, and maximal interlock BAC readings. Recidivism, dependence, high BAC, and combined fail rates were set as criteria; other variables were set as predictors. Area under the receiver operating characteristics (ROC) curve (A') estimates of sensitivity and specificity were calculated. Additional analyses were conducted on baseline hEtG levels. Driver performance and drinking indicators were evaluated against the standard hEtG cutoff for excessive drinking at (30 pg/mg) and a higher criterion of 50 pg/mg. HEtG splits were evaluated with the Mann-Whitney rank statistic.

Results: HEtG emerged as a top overall predictor for discriminating new recidivism events that occur after interlock installation, for entry alcohol dependence, and for the highest interlock BACs recorded. Together, hEtG and phosphatidylethanol (PEth) were the top predictors of all criterion measures. By contrast, the hair-derived alcohol biomarkers hEtG and hFAEE (fatty acid ethyl esters) were poorer than other alcohol biomarkers as detectors of interlock BAC test fail rates.

Conclusions: This study showed that hEtG, an objective alternative to often unreliable self-reported past representation of drinking levels, yields crucial insight into driver alcohol-related risks early in an interlock program and is a top predictor of new recidivist events. Together with PEth, these markers would be excellent anchors in a panel for detecting alcohol consumption.
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http://dx.doi.org/10.1080/15389588.2013.824569DOI Listing
March 2014

[What ethanol metabolites as biological markers tell us about alcohol use].

Wien Med Wochenschr 2014 Jan 10;164(1-2):25-33. Epub 2013 Dec 10.

Universitätsklinik für Psychiatrie und Psychotherapie II, Christian-Doppler-Klinik, Salzburger Landeskliniken, Paracelsus Medical University (PMU), Ignaz-Harrer-Straße 79, 5020, Salzburg, Österreich,

Alcohol and tobacco related disorders are the two leading and most expensive causes of illness in central Europe. In addition to self reports and questionnaires, biomarkers are of relevance in diagnosis and therapy of alcohol use disorders. Traditional biomarkers such as gamma glutamyl transpeptidase or mean corpuscular volume are indirect biomarkers and are subject to influence of age, gender and non alcohol related diseases, among others.Direct ethanol metabolites such as ethyl glucuronide (EtG), ethyl sulphate (EtS) and phosphatidylethanol (PEth) are direct metabolites of ethanol, that are positive after intake of ethyl alcohol. They represent useful diagnostic tools for identifying alcohol use even more accurately than traditional biomarkers. Each of these drinking indicators remains positive in serum and urine for a characteristic time spectrum after the cessation of ethanol intake--EtG and EtS in urine up to 7 days, EtG in hair for months after ethanol has left the body. Applications include clinical routine use, emergency room settings, proof of abstinence in alcohol rehabilitation programs, driving under influence offenders, workplace testing, assessment of alcohol intake in the context of liver transplantation and fetal alcohol syndrome.
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http://dx.doi.org/10.1007/s10354-013-0254-9DOI Listing
January 2014

Hair ethyl glucuronide levels as a marker for alcohol use and abuse: a review of the current state of the art.

Drug Alcohol Depend 2014 Jan 30;134:1-11. Epub 2013 Oct 30.

Toxicological Centre, University of Antwerp, Universiteitsplein 1, B2610 Antwerp, Belgium; Toxicology Laboratory, ZNA Stuivenberg, Lange Beeldekenstraat 267, B2060 Antwerp, Belgium.

Background: Ethyl glucuronide (EtG) is a minor alcohol metabolite that has been proposed as a stable marker in hair to detect and quantify alcohol consumption over long time periods.

Methods: We provide an outline of currently available techniques for EtG hair sample analysis and highlight the pitfalls related to data interpretation. The literature of EtG analysis has been reviewed from January 1980 up to August 2013. In addition, we present an overview of the clinical and forensic studies which have used EtG quantification in hair as a marker for alcohol consumption/abstinence and we provide suggestions for future research.

Results: EtG is a stable marker in hair that can be used to detect and quantify alcohol consumption over long time periods. This alcohol metabolite remains in hair after complete elimination of alcohol. Currently, there are three main analytical techniques used to quantify EtG in hair: gas chromatography-mass spectrometry (GC-MS), gas chromatography-tandem mass spectrometry (GC-MS/MS), and liquid chromatography-tandem mass spectrometry (LC-MS/MS). No standardized protocols are yet available for the analysis of EtG levels in hair samples, and the current protocols vary in sample preparation and extraction procedures. Variables such as hair length, cosmetic treatment, gender, and pathophysiological conditions influence the final results and should be taken into account.

Conclusions: EtG quantification in hair is a useful tool for the objective detection of alcohol consumption over extended time periods, but care should be taken when interpreting the results.
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http://dx.doi.org/10.1016/j.drugalcdep.2013.10.008DOI Listing
January 2014

Pregabalin determination in hair by ultra-high-performance liquid chromatography-tandem mass spectrometry.

J Anal Toxicol 2013 Nov-Dec;37(9):676-9. Epub 2013 Sep 19.

Department of Toxicology, Laboratoire National de Santé, Avenue de la Faiencerie, 162 A, L-1511 Luxembourg, Luxembourg.

Pregabalin is an antiepileptic and analgesic drug, commercialized under the name of Lyrica, and generally used to treat neuropathic pain. The determination of pregabalin was performed by using spiked hair samples extracted in methanol and analyzed by ultra-high-performance liquid chromatography coupled with tandem mass spectrometry. The validation of a quantification method of pregabalin in hair has been successfully achieved (precision, accuracy, matrix effects and extraction yield). The limit of detection was 0.76 pg/mg and the lower limit of quantification was 2.5 pg/mg. A real case of pregabalin in hair has been analyzed using this method. The result showed a concentration of 540 pg/mg.
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http://dx.doi.org/10.1093/jat/bkt081DOI Listing
December 2013

Coloring, bleaching, and perming: influence on EtG content in hair.

Ther Drug Monit 2013 Aug;35(4):527-9

Laboratoire National de Santé-Toxicologie, Université du Luxembourg, Campus Limpertsberg, Luxembourg.

Background: Hair analysis of ethyl glucuronide (EtG) has become, beside fatty acid ethyl ester, a valuable marker for the detection of moderate and chronic excessive alcohol consumption. So far, only few studies exist about the influence of cosmetic treatment on EtG content in hair. The aim of this study was to evaluate the effect of coloring, bleaching, and perming on the concentration of this alcohol marker in hair. Studies were also performed to evaluate the chemical stability of EtG in the presence of hydrogen peroxide and ammonium thioglycolate.

Methods: Six air samples were treated in vitro by the different commercial cosmetics following the suppliers' instructions. After washing, pulverization, incubation in ultrasonic bath, and solid phase extraction, EtG was determined by GC/MS-NICI after solid phase extraction and heptafluorobutyric anhydride derivatization.

Results: The results showed that samples (n = 10) treated with the coloring product did not show any important change in the EtG results. In the bleaching study (n = 23), a mean decrease of 73.5% was observed. After incubation of a solution of EtG with hydrogen peroxide (15%), a decrease of 45% was shown supporting the hypothesis of a chemical degradation of EtG and a leaching out effect from the hair matrix. In the perm treatment study (n = 23), a mean decrease of 95.7% of EtG was found. Incubation of a solution of EtG with ammonium thioglycolate (5%) showed a total decrease of EtG supporting the hypothesis of a chemical degradation.

Conclusions: Coloring treatment did not importantly influence EtG content in hair. However, an important decrease of EtG in hair could be found after bleaching and permanent wave treatment. This decrease seems to be because of a chemical degradation of EtG, after bleaching, and a leaching out effect from the matrix. After perming, it seems to be more of a chemical degradation of EtG. These data have to be considered for the correct interpretation of EtG amounts in hair.
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http://dx.doi.org/10.1097/FTD.0b013e31828ca246DOI Listing
August 2013

Determination of ethyl glucuronide in hair improves evaluation of long-term alcohol abstention in liver transplant candidates.

Liver Int 2014 Mar 7;34(3):469-76. Epub 2013 Jul 7.

Department of Hepatobiliary and Transplant Surgery, University Medical Center Hamburg - Eppendorf, Hamburg, Germany.

Background & Aims: Prior to listing patients for Orthotopic liver transplantation (OLT) an abstention period of 6 months is required. Ethyl glucuronide in the hair is a new reliable marker for the assessment of alcohol consumption. Here, the diagnostic value of determining the ethyl glucuronide concentration in the hair of liver transplant candidates was evaluated.

Methods: In 63 transplant candidates with alcoholic liver cirrhosis and 25 control patients with cirrhosis of other aetiologies alcohol markers, i.e. hEtG, urine EtG, blood ethanol, methanol and carbohydrate deficient transferrin were determined in parallel to an interview with a psychologist.

Results: A total of 19 (30%) transplant candidates admitted alcohol consumption within the last 6 months, while 39/63 (62%) were positive for at least one alcohol marker. In 52% of the 44 candidates denying alcohol consumption, abstention was disproved by detecting at least one positive alcohol marker, in 83% of cases by a positive hEtG result. In the control patients stating abstention from alcohol all hEtG tests were negative. No impact of renal or liver function on hEtG results was detected. A specificity of 98% and a positive predictive value of 92% were calculated for testing hEtG in proximal hair segment and applying a cut-off of 30 pg/mg.

Conclusions: In 52% of patients denying alcohol consumption within the last 6 months, alcohol abstention was disproved, in 83% of cases by hEtG testing. Therefore, hEtG is a promising new marker for the evaluation of long-term alcohol abstention in liver transplant candidates.
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http://dx.doi.org/10.1111/liv.12243DOI Listing
March 2014

The influence of ethanol containing cosmetics on ethyl glucuronide concentration in hair.

Forensic Sci Int 2012 May 1;218(1-3):123-5. Epub 2011 Nov 1.

Laboratoire National de Santé - Toxicologie, Université du Luxembourg, Campus Limpertsberg, 162a, Av. De la Faïencerie, L-1511 Luxembourg, Luxembourg.

Ethyl glucuronide (EtG) and fatty acid ethyl esters (FAEE), non-volatile, direct metabolites of ethanol have been shown to be suitable markers for the evaluation of social and chronic excessive alcohol consumption. Previous investigations have shown that the regular use of hair-care products with high alcohol content lead to an increase of FAEE concentration and consequently gave false-positive results for the determination of FAEE in hair. In this study we investigated the influence of a long-term hair treatment with EtOH containing lotion, on the EtG concentrations in hair. In this study 7 volunteer subjects (classified as either rare, social or heavy drinkers) treated the right side of their scalp every day during a one or two month period with a commercial hair tonic (Seborin), which contains 44.0% ethanol (vol%). Collection of hair specimens from both sides of the scalp was done one day before hair treatment, one week and one month after treatment (for 5 subjects also after two months of treatment). A hair segment of 3 centimeters (cm) was cut and then washed with water and acetone, and then pulverized. EtG was quantified by GC/MS after pulverization and 2h of ultrasonication in water, extraction by solid phase extraction using Oasis MAX columns and derivatization with HFBA. Measurements were done in negative chemical ionization mode using EtG-D5 as internal standard. Comparison of EtG concentration in the treated and in the non-treated hair specimens did not show any increase at the different dates of collection for the 7 subjects. In conclusion, these results show that there is no indication for an increase of EtG after use of ethanol containing hair cosmetics.
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http://dx.doi.org/10.1016/j.forsciint.2011.10.015DOI Listing
May 2012

Can ethyl glucuronide in hair be determined only in 3 cm hair strands?

Forensic Sci Int 2012 May 22;218(1-3):3-9. Epub 2011 Oct 22.

Labor Krone, Siemensstr. 40, 32105 Bad Salzuflen, Germany.

This paper addresses the suitability of ethyl glucuronide in hair (EtGH) strands other than 3cm for alcohol consumption. This issue will be addressed (a) by statistically comparing the distribution of EtGH results for 3cm hair strands to other hair strands analysed from 4126 cases and (b) by examining the stability of EtGH in an 8cm hair strand and two 12cm hair samples of two volunteers and a post-mortem case using 1cm segmental analysis. For 3464 driving license re-granting Medical and Psychological Assessment (MPA) cases, the detection of alcohol consumption using hair lengths longer than 3cm was never significantly less than for 3cm hair lengths, even up to 12cm hair lengths analysed non-segmented. For 662 non-MPA cases, where, in contrast to MPA cases, generally no abstinence was required, an increase in the EtGH positivity rate was observed with increasing hair length analysed up to 9cm, indicating that EtG-washout effects seem to play a minor role if any. For both MPA and non-MPA hair samples less than 3cm, a drastic, significant increase in the number of positive EtGH samples were observed, compared to 3cm hair lengths, strongly supportive of EtGH incorporation from sweat after a recent alcohol consumption. Segmental studies indicated that EtG is stable in the hair matrix up to 12cm long, hence supporting the above results. Even though both the statistical and the stability studies are preliminary results which need to be confirmed by other studies, they both provide evidence for the determination of alcohol consumption using EtGH in hair lengths longer than 3cm. Amendments to the Consensus of the Society of Hair Testing, the German driving license re-granting guidelines and EWDTS hair guidelines with respect to testing for abstinence and/or alcoholism are proposed for the benefit of the donors.
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http://dx.doi.org/10.1016/j.forsciint.2011.10.001DOI Listing
May 2012
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