Elimination of matrix effects in urine for determination of ethyl glucuronide by liquid chromatography-tandem mass spectrometry.

RATIONALE: Alcohol use disorder affects 4% to 5% of the world's population. Analysis methods are available for various biological fluids to detect this disorder. Determination of ethyl glucuronide in urine by the liquid chromatography-tandem mass spectrometry (LC/MS/MS) method is frequently used in forensic toxicology. These analyses are known to cause matrix effects. METHODS: The presented study describes the elimination of matrix effects for ethyl glucuronide. This study used two different LC/MS/MS systems containing orthogonal and z-spray ion sources. Ethyl glucuronide was analyzed in negative polarity in electrospray ionization. A different dilution method was chosen for each study. The methods were developed and validated according to the European Medicines Agency bioanalytical method validation parameters. RESULTS: The lower limit of quantitation of the developed methods was 0.025 µg/mL for ethyl glucuronide. The calibration curve of ethyl glucuronide was between 0.025 and 100 µg/mL with a correlation coefficient of >0.99 for the two methods. CONCLUSIONS: It was determined that the analyses using the z-spray ion source were more affected by the matrix effect. The two validated methods involve rapid analysis time and simple sample preparation. Also, the methods were applied to real patients' urine.

Concordance Between Point-of-Care Urine Ethyl Glucuronide Alcohol Tests and Self-Reported Alcohol Use in Persons with HIV in Uganda.

Screening and assessing alcohol use accurately to maximize positive treatment outcomes remain problematic in regions with high rates of alcohol use and HIV and TB infections. In this study, we examined the concordance between self-reported measures of alcohol use and point-of-care (POC) urine ethyl glucuronide (uEtG) test results among persons with HIV (PWH) in Uganda who reported drinking in the prior 3 months. For analyses, we used the screening data of a trial designed to examine the use of incentives to reduce alcohol consumption and increase medication adherence to examine the concordance between POC uEtG (300 ng/mL cutoff) and six measures of self-reported alcohol use. Of the 2136 participants who completed the alcohol screening, 1080 (50.6%) tested positive in the POC uEtG test, and 1756 (82.2%) self-reported using alcohol during the prior 72 h. Seventy-two percent of those who reported drinking during the prior 24 h had a uEtG positive test, with lower proportions testing uEtG positive when drinking occurred 24-48 h (64.7%) or 48-72 h (28.6%) prior to sample collection. In multivariate models, recency of drinking, number of drinks at last alcohol use, and Alcohol Use Disorders Identification Test - Consumption (AUDIT-C) score were associated with uEtG positivity. The highest area under the curve (AUC) for a uEtG positive test was for recency of drinking. Overall, we concluded that several measures of drinking were associated with POC uEtG positivity, with recency of drinking, particularly drinking within the past 24 h, being the strongest predictor of uEtG positivity.

Ethyl Glucuronide and Ethyl Sulphate in Urine: Caution in their use as markers of recent alcohol use.

AIM: To clarify the role of the ethanol metabolites, ethyl glucuronide (EtG) and ethyl sulfate (EtS), in monitoring alcohol consumption. METHOD: We recruited 7 female and 17 male volunteers who were instructed to consume a quantity of beer (containing 48 gm ethanol) with food in one session. We examined urinary excretion of EtG and EtS over time and looked for correlations between the concentrations of the metabolites EtG and EtS. RESULTS: EtG concentrations in urine varied between 0.026 and 430.372 µg/ml with average values between 11.85 µg/ml (SD 19.75), 30 min after alcohol intake, and 100.39 µg/ml (SD 101.34), 4.5 h after alcohol intake. EtS urinary concentration ranged from 0.006 to 101.432 µg/ml with average values between 4.77 µg/ml (SD 5.42), 30 min after alcohol intake, and 30.14 µg/ml (SD 27.20), 4.5 h after alcohol intake. Spearman's test showed that urinary EtG and EtS correlated significantly at several time points. CONCLUSION: The great interindividual variability in their excretion suggests caution in the use of urinary measurement of these metabolites in forensic investigations.

As3MT and GST Polymorphisms Influencing Arsenic Metabolism in Human Exposure to Drinking Groundwater.

The urinary arsenic metabolites may vary among individuals and the genetic factors have been reported to explain part of the variation. We assessed the influence of polymorphic variants of Arsenic-3-methyl-transferase and Glutathione-S-transferase on urinary arsenic metabolites. Twenty-two groundwater wells for human consumption from municipalities of Colombia were analyzed for assessed the exposure by lifetime average daily dose (LADD) (µg/kg bw/day). Surveys on 151 participants aged between 18 and 81 years old were applied to collect demographic information and other factors. In addition, genetic polymorphisms (GSTO2-rs156697, GSTP1-rs1695, As3MT-rs3740400, GSTT1 and GSTM1) were evaluated by real time and/or conventional PCR. Arsenic metabolites: AsIII, AsV, monomethylarsonic acid (MMA), and dimethylarsinic acid (DMA) were measured using HPLC-HG-AFS. The influence of polymorphic variants, LADD and other factors were tested using multivariate analyses. The median of total arsenic concentration in groundwater was of 33.3 µg/L and the median of LADD for the high exposure dose was 0.33 µg/kg bw/day. Univariate analyses among arsenic metabolites and genetic polymorphisms showed MMA concentrations higher in heterozygous and/or homozygous genotypes of As3MT compared to the wild-type genotype. Besides, DMA concentrations were lower in heterozygous and/or homozygous genotypes of GSTP1 compared to the wild-type genotype. Both DMA and MMA concentrations were higher in GSTM1-null genotypes compared to the active genotype. Multivariate analyses showed statistically significant association among interactions gene-gene and gene-covariates to modify the MMA and DMA excretion. Interactions between polymorphic variants As3MT*GSTM1 and GSTO2*GSTP1 could be potential modifiers of urinary excretion of arsenic and covariates as age, LADD, and alcohol consumption contribute to largely vary the arsenic individual metabolic capacity in exposed people.

An Ultrahigh-Performance Liquid Chromatography-Time-of-Flight Mass Spectrometry Metabolomic Approach to Studying the Impact of Moderate Red-Wine Consumption on Urinary Metabolome.

Moderate red-wine consumption has been widely described to exert several benefits in human health. This is mainly due to its unique content of bioactive polyphenols, which suffer several modifications along their pass through the digestive system, including microbial transformation in the colon and phase-II metabolism, until they are finally excreted in urine and feces. To determine the impact of moderate wine consumption in the overall urinary metabolome of healthy volunteers ( n = 41), samples from a red-wine interventional study (250 mL/day, 28 days) were investigated. Urine (24 h) was collected before and after intervention and analyzed by an untargeted ultrahigh-performance liquid chromatography-time-of-flight mass spectrometry metabolomics approach. 94 compounds linked to wine consumption, including specific wine components (tartaric acid), microbial-derived phenolic metabolites (5-(dihydroxyphenyl)-γ-valerolactones and 4-hydroxyl-5-(phenyl)-valeric acids), and endogenous compounds were identified. Also, some relationships between parallel fecal and urinary metabolomes are discussed.

Text Messaging to Reduce Alcohol Relapse in Prelisting Liver Transplant Candidates: A Pilot Feasibility Study.

BACKGROUND: Many liver transplantation programs require documented alcohol sobriety prior to United Network for Organ Sharing (UNOS) listing. This pilot study examined the feasibility of the first mobile, alcohol relapse prevention intervention for liver transplant patients with alcoholic liver disease (ALD). METHODS: This was a randomized 8-week pilot feasibility trial of a text message-based alcohol intervention. In-treatment assessment was conducted at 4 weeks (4W), and immediate posttreatment assessment was conducted at 8W. Participants were liver transplant candidates (N = 15) diagnosed with ALD who reported at least 1 drinking episode in the past year. Primary feasibility outcomes were percent of messages responded to and posttreatment intervention satisfaction ratings. Preliminary clinical efficacy outcomes were any biologically confirmed alcohol consumption, stress, abstinence self-efficacy, and alcohol craving. RESULTS: On feasibility outcomes, participants responded to 81% of messages received and reported high rates of intervention satisfaction, looked forward to receiving the messages, and found it easy to complete the intervention. On preliminary efficacy outcomes, zero participants in the text message (TM) had positive urine alcohol tests at 8W. Two of the 6 participants in standard care (SC) tested positive at 8W. No effects were seen on craving. For stress, a condition × time interaction emerged. TM participants had less stress at 4W and 8W compared with SC at baseline. They maintained their stress level during the intervention. For self-efficacy, a trend for condition effect emerged. TM participants had higher self-efficacy than SC participants. CONCLUSIONS: Participants reported high satisfaction with the intervention, looked forward to the messages, and found it easy to complete. Participants who received the intervention had better treatment outcomes than those who received standard care. They maintained higher levels of self-efficacy and lower stress. Mobile alcohol interventions may hold significant promise to help ALD liver transplant patients maintain sobriety.

Point-of-Care Urine Ethyl Glucuronide Testing to Detect Alcohol Use Among HIV-Hepatitis B Virus Coinfected Adults in Zambia.

In an HIV-hepatitis B virus (HIV-HBV) coinfection cohort in Zambia, we piloted a qualitative point-of-care (POC) test for urine Ethyl glucuronide (uEtG), assessed concordance between uEtG and alcohol use disorders identification test-consumption (AUDIT-C), and identified epidemiological factors associated with underreporting (defined as uEtG-positivity with last reported drink > 7 days prior). Among 211 participants (40.8% women), there were 44 (20.8%) lifetime abstainers, 32 (15.2%) former drinkers, and 135 (64.0%) current drinkers, including 106 (50.2%) with unhealthy drinking per AUDIT-C. Eighty-seven (41.2%) were uEtG-positive including 64 of 65 (98.5%) who drank ≤ 3 days prior and 17 of 134 (12.7%) underreported, all of whom admitted to recent drinking when results were discussed. uEtG was moderately concordant with AUDIT-C. Past drinking (versus lifetime abstinence) and longer time on antiretrovirals (≥ 12 months) were associated with underreporting. These data support further use of POC alcohol biomarkers in HIV and hepatitis research and clinical settings.

Phosphatidylethanol (PEth) detected in blood for 3 to 12 days after single consumption of alcohol-a drinking study with 16 volunteers.

In most studies, the alcohol marker phosphatidylethanol (PEth) was used to differentiate social drinking from alcohol abuse. This study investigates PEth's potential in abstinence monitoring by performing a drinking study to assess the detection window of PEth after ingesting a defined amount of alcohol. After 2 weeks of abstinence, 16 volunteers ingested a single dose of alcohol, leading to an estimated blood alcohol concentration (BAC) of 1 g/kg. In the week after drinking, blood and urine samples were taken daily; in the second week, samples were taken every other day. PEth 16:0/18:1 and 16:0/18:2 were analyzed in blood by online-SPE-LC-MS/MS. Ethyl glucuronide and ethyl sulfate were determined in urine for abstinence monitoring. Prior to start of drinking, PEth 16:0/18:1 exceeded 30 ng/mL in blood samples of five volunteers despite the requested abstinence period. Positive PEth values resulted from drinking events prior to this abstinence period. After the start of drinking, maximum BACs were reached after 2 h with a mean of 0.80 ± 0.13 g/kg (range: 0.61-1.11 g/kg). PEth 16:0/18:1 increased within 8 h to maximum concentrations (mean: 88.8 ± 47.0 ng/mL, range: 37.2-208 ng/mL). After this event, PEth was detectable for 3 to 12 days with a mean half-life time of approximately 3 days. PEth has a potential in abstinence monitoring, since PEth could be detected for up to 12 days after a single drinking event. Further investigations are necessary, to establish cut-off levels for PEth as diagnostic marker for the determination of drinking habits like abstinence, social drinking, or risky alcohol consumption.

Introduction of sample tubes with sodium azide as a preservative for ethyl glucuronide in urine.

Ethyl glucuronide (EtG) is a direct alcohol marker, which is widely used for clinical and forensic applications, mainly for abstinence control. However, the instability of EtG in urine against bacterial degradation or the post-collectional synthesis of EtG in contaminated samples may cause false interpretation of EtG results in urine samples. This study evaluates the potential of sodium azide in tubes used for urine collection to hinder degradation of ethyl glucuronide by bacterial metabolism taking place during growth of bacterial colonies. The tubes are part of a commercial oral fluid collection device. The sampling system was tested with different gram-positive and gram-negative bacterial species previously observed in urinary tract infections, such as Escherichia coli, Staphylococcus aureus, Enterecoccus faecalis, Staphylococcus epidermidis, Klebsiella pneumoniae, Enterobacter cloacae, and Pseudomonas aeruginosa. Inhibition of bacterial growth by sodium azide, resulting in lower numbers of colony forming units compared to control samples, was observed for all tested bacterial species. To test the prevention of EtG degradation by the predominant pathogen in urinary tract infection, sterile-filtered urine and deficient medium were spiked with EtG, and inoculated with E. coli prior to incubation for 4 days at 37 °C in tubes with and without sodium azide. Samples were collected every 24 hours, during four consecutive days, whereby the colony forming units (CFU) were counted on Columbia blood agar plates, and EtG was analyzed by LC-MS/MS. As expected, EtG degradation was observed when standard polypropylene tubes were used for the storage of contaminated samples. However, urine specimens collected in sodium azide tubes showed no or very limited bacterial growth and no EtG degradation. As a conclusion, sodium azide is useful to reduce bacterial growth of gram-negative and gram-positive bacteria. It inhibits the degradation of EtG by E. coli and can be used for the stabilization of EtG in urine samples.

Improved detection of alcohol consumption using the novel marker phosphatidylethanol in the transplant setting: results of a prospective study.

Phosphatidylethanol (PEth) is a new, highly specific alcohol marker. The aim of this study was to assess its diagnostic value in the liver transplant setting. In 51 pre- and 61 post-transplant patients with underlying alcoholic liver disease PEth, ethanol, methanol, carbohydrate-deficient transferrin (CDT), and ethyl glucuronide in urine (uEtG) and hair (hEtG) were tested and compared with patients' questionnaire reports. Twenty-eight (25%) patients tested positive for at least one alcohol marker. PEth alone revealed alcohol consumption in 18% of patients. With respect to detection of alcohol intake in the preceding week, PEth showed a 100% sensitivity. PEth testing was more sensitive than the determination of ethanol, methanol, CDT or uEtG alone [sensitivity 25% (confidence interval (CI) 95%, 7-52%), 25% (7-52%), 21% (6-45%) and 71% (41-91%), respectively], or ethanol, methanol and uEtG taken in combination with 73% (45-92%). Specificity of all markers was 92% or higher. Additional testing of hEtG revealed alcohol consumption in seven patients, not being positive for any other marker. Phosphatidylethanol was a highly specific and sensitive marker for detection of recent alcohol consumption in pre- and post-transplant patients. The additional determination of hEtG was useful in disclosing alcohol consumption 3-6 months retrospectively.

Blood mercury concentrations are associated with decline in liver function in an elderly population: a panel study.

BACKGROUND: Mercury is a toxic heavy metal and is known to affect many diseases. However, few studies have examined the effects of mercury exposure on liver function in the general population. We examined the association between blood mercury concentrations and liver enzyme levels in the elderly. METHODS: We included 560 elderly participants (60 years or older) who were recruited from 2008 to 2010 and followed up to 2014. Subjects visited a community welfare center and underwent a medical examination and measurement of mercury levels up to five times. Analyses using generalized estimating equations model were performed after adjusting for age, sex, education, overweight, alcohol consumption, smoking, regular exercise, high-density lipoproteins cholesterol, and total calorie intake. Additionally, we estimated interaction effects of alcohol consumption with mercury and mediation effect of oxidative stress in the relationship between mercury levels and liver function. RESULTS: The geometric mean (95% confidence interval (CI)) of blood mercury concentrations was 2.81 µg/L (2.73, 2.89). Significant relationships were observed between blood mercury concentrations and the level of liver enzymes, including aspartate aminotransferase (AST), alanine aminotransferase (ALT), and gamma glutamyl transferase (GGT), after adjusting for potential confounders (P < 0.05). The odds ratios of having abnormal ALT levels were statistically significant in the highest mercury quartile compared to those with the lowest quartile. Particularly, regular alcohol drinkers showed greater effect estimates of mercury on the liver function than non-drinkers groups. There was no mediation effect of oxidative stress in the relationship between blood mercury concentrations and liver function. CONCLUSIONS: Our results suggest that blood mercury levels are associated with elevated liver enzymes and interact with alcohol consumption for the association in the elderly.

Biomarkers of the alcohol hangover state: Ethyl glucuronide (EtG) and ethyl sulfate (EtS).

INTRODUCTION: The aim of this study was to investigate the usefulness of ethyl glucuronide (EtG) and ethyl sulfate (EtS) as biomarkers of the hangover state. METHODS: Thirty-sixhealthy social drinkers participated in this study, being of naturalistic design. Eighteen participants experience regular hangovers (the hangover group), whereas the other 18 claim to not experience a hangover (the hangover-immune group). On a control day (alcohol-free) day and a post-alcohol day, urine EtG and EtS concentrations were determined and hangover severity assessed. RESULTS: Urinary EtG and EtS concentrations were significantly increased on post-alcohol day compared to the control day (p = .0001). Both EtG and EtS concentrations did not significantly correlate with the overall hangover score, nor with the estimated peak blood alcohol concentrations and number of alcoholic drinks. EtG correlated significantly only with the individual hangover symptom "headache" (p = .033; r = .403). No significant correlations were found with the EtG to EtS ratio. EtG and EtS concentrations significantly correlated with urine ethanol concentrations. CONCLUSIONS: Although urine EtG and EtS concentration did not significantly correlate to estimated peak blood alcohol concentrations or the number of alcoholic drinks consumed, a significant correlation was found with urine ethanol concentration. However, urine EtG and EtS concentrations did not significantly correlate with overall hangover severity.

The Performance of Alcohol Markers Including Ethyl Glucuronide and Ethyl Sulphate to Detect Alcohol Use in Clients in a Community Alcohol Treatment Programme.

AIMS: The ethanol metabolites ethyl glucuronide (EtG) and ethyl sulphate (EtS) are detectable for longer in urine than breath ethanol or urine ethanol after alcohol intake. This study compared the performance of breath ethanol, urine ethanol, urine EtG and EtS to detect alcohol consumption in clients in community alcohol treatment. METHODS: Clients attending the community alcohol treatment programme were asked to provide an alcohol diary, breathalyser test and urine for ethanol, EtG and EtS measurement (n = 42). Positive results were defined using the detection limits (breath ethanol and urine ethanol) or clinical cut-offs (EtG: 0.26 mg/L and EtS: 0.22 mg/L). The sensitivities and specificities of each marker to detect alcohol intake <24 and 48-72 h prior were calculated. RESULTS: The sensitivities of each alcohol marker to detect alcohol intake <24 h prior were 57, 71, 100 and 100% for breath ethanol, urine ethanol, urine EtG and urine EtS, respectively. The specificity was 100% for urine ethanol and urine EtS. The EtG specificity could be increased to 100% by using a higher cut-off (0.50 mg/L). The sensitivity of all markers (including EtG and EtS) to detect alcohol intake of ≤10 units 48-72 h earlier decreased to 0%. CONCLUSIONS: In community alcohol treatment clients, urine EtG and EtS showed the optimum diagnostic performance to detect alcohol intake in the previous 24 h. We propose a flowchart to routinely use EtG and EtS for clients in community alcohol treatment. SHORT SUMMARY: The ability of breath ethanol, urine ethanol, urine EtG and urine EtS to detect continued alcohol consumption in clients in community alcohol treatment were compared. Urine EtG and EtS showed the optimum diagnostic performance and we propose a flowchart to routinely use EtG and EtS in community alcohol treatment.

Detecting Beer Intake by Unique Metabolite Patterns.

Evaluation of the health related effects of beer intake is hampered by the lack of accurate tools for assessing intakes (biomarkers). Therefore, we identified plasma and urine metabolites associated with recent beer intake by untargeted metabolomics and established a characteristic metabolite pattern representing raw materials and beer production as a qualitative biomarker of beer intake. In a randomized, crossover, single-blinded meal study (MSt1), 18 participants were given, one at a time, four different test beverages: strong, regular, and nonalcoholic beers and a soft drink. Four participants were assigned to have two additional beers (MSt2). In addition to plasma and urine samples, test beverages, wort, and hops extract were analyzed by UPLC-QTOF. A unique metabolite pattern reflecting beer metabolome, including metabolites derived from beer raw material (i.e., N-methyl tyramine sulfate and the sum of iso-α-acids and tricyclohumols) and the production process (i.e., pyro-glutamyl proline and 2-ethyl malate), was selected to establish a compliance biomarker model for detection of beer intake based on MSt1. The model predicted the MSt2 samples collected before and up to 12 h after beer intake correctly (AUC = 1). A biomarker model including four metabolites representing both beer raw materials and production steps provided a specific and accurate tool for measurement of beer consumption.

Detection of the ethanol consumption markers ethyl glucuronide and ethyl sulfate in urine samples from inmates of two German prisons.

INTRODUCTION: Abstinence from ethanol is necessary in various situations. Among these are jail terms. Nevertheless, it is a matter of fact that ethanol is illegally produced and ingested in prisons. So far, data regarding drug prevalence in jail have mainly been collected by questionnaires. To get an objective database for the prevalence of ethanol consumption in jail, a cross-sectional study was performed. METHODS: Inmates of two German prisons (Offenburg and Freiburg) were asked to give a urine sample at an unknown and random point of time. Participation was voluntary and did lead to neither negative consequences nor benefits. All samples were anonymized. Using the consumption markers ethyl glucuronide (EtG) and ethyl sulfate (EtS), the urine samples were tested for previous ethanol consumption. Analyses were performed by a validated liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. RESULTS: In total 676 male inmates participated in this study. The participation rate was 70-75% of all permanent inmates in Offenburg and 30.6% in Freiburg. Ten of the 555 (1.8%) samples from Offenburg and 1 of the 121 (0.8%) samples from Freiburg were positive for ethanol consumption markers with concentrations ranging from trace amounts to 1400 ng/mL for EtG and up to 510 ng/mL for EtS, respectively. CONCLUSIONS: The number of participants in this study was rather high, so that the results represent a good cross section, at least for Offenburg, the jail with the higher number of positive samples.

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

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.

N-Acetyltaurine as a novel urinary ethanol marker in a drinking study.

The forensic utility of N-acetyltaurine (NAcT) in urine as a marker for ethanol intake was examined. A HILIC-based liquid chromatography method for the mass spectrometric determination of NAcT, taurine, and creatinine in urine was developed and validated to investigate NAcT formation and elimination in a drinking study. Thereby, eight subjects ingested 0.66 to 0.84 g/kg alcohol to reach a blood alcohol concentration (BAC) of 0.8 g/kg. Blood and urine were taken every 1.5-2 h, during the first 8 h. NAcT and taurine levels were measured and corrected for the urine's dilution by normalization to a creatinine concentration of 1 mg/mL. For the determination of NAcT and taurine, uncorrected lower limits of quantitation (LLOQs) were at 0.05 µg/mL of urine. In the drinking study, NAcT proved to be an endogenous compound, which is present at a range of 1.0 to 2.3 µg/mL in urine of alcohol-abstinent subjects. Maximum NAcT concentrations were reached in samples taken 3 to 6 h after the start of drinking, whereby an upregulation in N-acetyltaurine could be found for all the subjects. The mean peak concentrations (c̅ max) of 14 ± 2.6 µg/mL (range 9-17.5 µg/mL) were reached. Within 24 h, the NAcT levels declined to endogenous concentrations. The detectability of NAcT was found to be slightly shifted compared to BAC: When BAC was not detectable anymore, NAcT levels were still elevated. After 24 h, when ethyl glucuronide (EtG) and ethyl sulfate (EtS) were still detectable, NAcT concentrations showed endogenous levels again. Positive NAcT results can be used as an indicator for recent alcohol consumption. A direct relationship between NAcT and taurine concentrations could not be found. Graphical abstract N-acetyltaurine concentrations for eight subjects during the first 24 h after an alcohol consumption of 0.8 g/kg.

Determination of total urinary 2,5-hexanedione in the Chinese general population.

OBJECTIVE: Determination of the urinary levels of 2.5-hexanedione (2,5-HD) was performed in subjects belonging to the Chinese general population to define the reference value for this metabolite. METHODS: Urine samples were collected from 8235 individuals (4216 men and 4019 women) from the healthy general population who had not been occupationally exposed to n-hexane or methyl-n-butyl ketone. The determination was performed by a gas chromatography mass spectrometry method using an ion-trap mass spectrometer. RESULTS: The result showed that the urinary 2,5-HD median level was 0.159mg/L for the total samples. Males had statistically significant higher excretion of 2,5-HD in urine than females (median 0.171mg/L compared to 0.147mg/L, Z=-8.21, P<0.001). There was a statistically significant difference in urinary 2,5-HD levels among age groups. The excretion of 2,5-HD in urine was related to increasing age (r=-0.160, P<0.05). There was statistically significant difference in urinary 2,5-HD levels among people from difference provinces. The results showed that there was also a statistically significant effect in urinary 2,5-HD levels between current smokers and non-smokers. CONCLUSION: Finding a measurable amount of 2,5-HD in urine does not mean that the level of 2,5-HD causes an adverse health effect. Biomonitoring studies on levels of urinary 2,5-HD can provide physicians and public health officials with reference values so that they can determine whether people have been exposed to higher levels of 2,5-HD than are found in the Chinese general population. These data can also provide a foundation for scientists to make a plan for further study.

Evaluation of biomarkers assessing regular alcohol consumption in an occupational setting.

PURPOSE: An estimation of ethanol intake is frequently of importance in the frame work of studies, but not trivial to achieve. Problems are "underreporting", a very short time frame for the detection of ethanol as direct marker and interference of many in- and outside body factors with strain parameters. The aim of this study was to explore the suitability of the direct urinary biomarkers ethyl glucuronide (EtG) and ethyl sulphate (EtS) to assess moderate but regular alcohol consumption. MATERIALS AND METHODS: A total of 175 male workers without any known occupational contact to substances influencing liver functions or metabolism of ethanol were examined. Strain parameters of alcohol consumption, i.e. the liver function tests (LFTs: aspartate aminotransferase, alanine aminotransferase, gamma-glutamyltransferase), carbohydrate-deficient transferrin (CDT), mean corpuscular erythrocyte volume (MCV) and the markers of alcohol consumption (EtG and EtS) have been analysed and compared. RESULTS: Up to 14 % of workers had been outside reference range for strain parameters. 62.3 % of the workers had at least traceable amounts of EtG and 84.6 % of EtS. Values above cut-off (indicating voluntary ethanol intake) were found in 34.9 and 51.4 % of the workers for EtG and EtS, respectively. In multiple linear regression analyses, CDT and MCV but not the LFTs showed a dependency from the non-oxidative ethanol metabolites. The LFTs were influenced by BMI. CONCLUSION: Determination of EtG and EtS in urine is an adequate tool to assess moderate but regular alcohol consumption.

A descriptive regional study of drug and alcohol use in pregnant women using results from urine drug testing by liquid chromatography-tandem mass spectrometry.

BACKGROUND: Patterns of drug use during pregnancy may be changing. Identifying changes in pregnant women's drug use may help to target prevention and treatment. OBJECTIVE: To determine the regional prevalence of drug and alcohol use among pregnant women in Southern California. METHODS: This was a prospective, descriptive study conducted at a university health system's urban and suburban ambulatory obstetric offices. Included were pregnant women of all ages and trimesters. Excluded were non-pregnant women and women who had previously presented for an obstetric appointment during the data collection time period. Women provided a urine sample as part of routine care. Liquid chromatography-tandem mass spectrometry analysis of urine was performed for detection of a pre-selected sample of drugs and for alcohol. Descriptive statistics were performed. RESULTS: A total of 295 urine samples were included. All trimesters were represented. A total of 14.2% of urine samples were positive for at least one of the tested drugs or alcohol. Alcohol was detected in 6% of the urine samples and was the most frequently identified substance. Prescription opioid analgesics (3.7% detection rate) and marijuana (4% detection rate) were the other most frequently detected substances. CONCLUSIONS: Compared with older reports, our detection rates of prescription opioid analgesics were increased while rates of urinary alcohol detection were relatively unchanged, and detection rates of marijuana were decreased. Provider awareness of these substance detection rates may facilitate the identification of patients using these substances during pregnancy and ultimately help promote potential prevention and treatment.