Urine as a Biological Specimen for Forensic Analysis of Alcohol and Variability in the Urine-to-Blood Relationship

A review on forensic analysis of bio fluids (blood, semen, vaginal fluid, menstrual blood, urine, saliva): Spectroscopic and non-spectroscopic technique

The accurate detection, identification, and analysis of biofluids at crime scenes play a critical role in forensic investigations. Various biofluids, such as blood, semen, vaginal fluid, menstrual blood, urine, and saliva, can be crucial evidence. In a murder case involving a knife attack, for instance, bloodstains from both the victim and perpetrator might be present. Sexual assault cases often involve the analysis of semen and vaginal secretions. Biofluid analysis employs a two-tiered approach: presumptive tests for initial identification and confirmatory tests for definitive analysis. This review article focuses on six key biofluids and their forensic significance. In this review, we comprehensively explore the relevant analytical techniques, including non-spectroscopic methods like immunoassays, spot tests, and cytokine profiling, alongside spectroscopic techniques such as Infrared (IR) spectroscopy, Mass Spectrometry (MS), and Raman Spectroscopy (RS).

Postmortem/dynamic distribution of ethanol and its nonoxidative metabolites in poisoned rabbits

Nonoxidative ethanol metabolites have been reported as ethanol biomarkers in clinical and forensic cases. However, their forensic toxicokinetics are still unclear. The study aimed to simultaneously research the postmortem distribution and dynamic distribution of ethanol and its nonoxidative metabolites in 62 poisoned rabbits. Firstly, 32 rabbits were randomly divided into three groups and sacrificed after three doses ethanol, and their organs were collected to study the postmortem distribution of ethanol and its nonoxidative metabolites. The results showed that the distribution trends of ethanol and its nonoxidative metabolites were basically same between different groups, and ethanol could be better detected by collecting body fluids, while the nonoxidative metabolites could be better detected by collecting the heart, liver, kidney and testis. Secondly, 30 rabbits after 1/2LD50 ethanol intragastric administration were sacrificed at 10 time points, and their organs were collected to study the dynamic distribution of ethanol and its nonoxidative metabolites. The results showed the concentrations of ethanol and its nonoxidative metabolites increased with time and then decreased. All analytes could be detected in all samples within 8 h, with the exception of ethyl oleate, which kept high level in muscle and vitreous humor, and could be detected within 4 h.

Methanol intoxication in the central region of Saudi Arabia: Five case studies

Outbreaks of methanol poisoning have been described in the medical literature worldwide. However, the few outbreaks that have occurred in Saudi Arabia remain undocumented. This is especially noteworthy in light of the fact that Saudi Arabia is among the countries that explicitly prohibit the usage of alcoholic beverages and recreational drugs. Herein, we describe five cases of methanol poisoning in Saudi Arabia. The first three comprise patients admitted to the emergency room (ER) with signs of methanol toxicity, such as heart palpitations, vomiting, and blurred vision; otherwise, those patients were considered medically free. The remaining two cases were examined postmortem. A headspace gas chromatography-flame ionization detector was used to test blood, vitreous humor, and urine samples for methanol. Specific lethal concentrations of methanol were defined based on published case studies as 23-740 mg/dL in blood and 12-396 mg/dL in vitreous humor. In postmortem cases of our present study, samples exhibited lethal concentrations: 118 and 257 mg/dL in blood, 116.3 and 283 mg/dL in vitreous humor. In ER cases, methanol concentrations in urine samples were lower, at 7.5, 9.1, and 20.9 mg/dL; however, toxic symptoms were still observed. These case studies indicate that it is necessary to raise community awareness about the risk of methanol poisoning in order to minimize future poisoning epidemics.

Preanalytical factors influencing the results of ethanol analysis in postmortem specimens

Excessive drinking and drunkenness are underlying factors in many fatal accidents, which make the quantitative determination of ethanol in postmortem (PM) specimens an essential part of all unnatural death investigations. The same analytical methods are used to determine ethanol in blood taken from living and deceased persons although the interpretation of the results is more complicated in medical examiner cases owing to various preanalytical factors. The biggest problem is that under anaerobic conditions ethanol can be produced naturally in decomposed bodies by microbial activity and fermentation of blood glucose. Ways are needed to differentiate antemortem ingestion of ethanol from PM synthesis. One approach involves the determination of ethanol in alternative specimens, such as bile, cerebrospinal fluid, vitreous humor and/or urine, and comparison of results with blood alcohol concentration (BAC). Another approach involves the analysis of various alcohol biomarkers, such as ethyl glucuronide, ethyl sulfate and/or phosphatidylethanol or the urinary metabolites of serotonin 5-hydroxytryptophol/5-hydroxyindoleacetic acid (5-HTOL/5-HIAA). If ethanol had been produced in the body by microbial activity, the blood samples should also contain other low-molecular volatiles, such as acetaldehyde, n-propanol and/or n-butanol. The inclusion of 1-2% w/v sodium or potassium fluoride, as an enzyme inhibitor, in all PM specimens is essential to diminish the risk of ethanol being generated after sampling, such as during shipment and storage prior to analysis. Furthermore, much might be gained if the analytical cut-off for reporting positive BAC was raised from 0.01 to 0.02 g% when PM blood is analyzed. During putrefaction low BACs are more often produced after death than high BACs. Therefore, when the cadaver is obviously decomposed, a pragmatic approach would be to subtract 0.05 g% from the mean analytical result. Any remaining BAC is expected to give a more reliable indication of whether alcohol had been consumed before death.

Sudden cardiac death after alcohol intake: classification and autopsy findings

Alcohol is known to have an immediate effect on cardiac rhythm, and previous studies have found that a notable proportion of sudden cardiac deaths (SCD) occur after alcohol intake. The objective of the present study was to investigate the association between the timing of alcohol intake and SCD. Our study population is drawn from the Fingesture study, which includes 5869 consecutive SCD cases from Northern Finland who underwent medicolegal autopsy 1998–2017. Toxicological analysis was performed if there was any suspicion of toxic exposure, or if there was no obvious immediate cause of SCD at autopsy. We found that 1563 (27%) of all SCD victims had alcohol in blood or urine at autopsy (mean age (61 ± 10 years, 88% male). Eighty-six percent of alcohol-related SCD victims had higher urine alcohol concentration than blood alcohol concentration, referring to the late-stage inebriation. These results suggest that the majority of alcohol-related SCDs occur at the late stage of inebriation.

Pooled Urine Analysis at a Belgian Music Festival: Trends in Alcohol Consumption and Recreational Drug Use

BACKGROUND

Recreational drug use has become more and more accepted in society. Availability and purity are rising and new psychoactive substances (NPS) are popping up.The aim of this study was to provide objective data on illicit drug use at a Belgian festival in order to report on arising trends. This may provide additional information to help develop preventive strategies.

METHODS

A cross-sectional study took place during a music festival in the summer of 2019, where 43 samples of pooled urine were collected at four different locations and at different moments of the day. Analysis was performed using gas chromatography with a flame ionization detector (GC-FID) to determine ethanol concentrations. Drugs of abuse were quantified using liquid chromatography-tandem mass spectrometry. A qualitative analysis was performed using high-resolution mass spectrometry.

RESULTS

Median ethanol concentration was 0.88g/L. Cocaine, 3,4-methylenedioxymethamphetamine (MDMA), amphetamines, ketamine, and cannabis were detected in almost every sample and often in high concentrations. Furthermore, two NPS were detected and a variety of over-the-counter medication and adulterants were also found.

DISCUSSION

The findings were largely in-line with trends outlined in the European Drug Report. Striking were the relatively high concentrations of MDMA and ketamine and detection of two synthetic cathinones. Two possible adulterants of cocaine were detected, namely flecainide and amlodipine.

CONCLUSION

Music festivals are considered a high-risk setting for alcohol consumption and illicit drug use. Analysis of pooled urine samples at a festival therefore provides a valuable method to evaluate trends and to screen for new substances. Wide-spread use of classical drugs and identification of two NPS were observed during a major international music festival in Belgium. Results need to be interpreted carefully, taking into account the possibilities and limitations of the used techniques and a standardized sampling is required.

Research Progress of Graphene and Its Derivatives towards Exhaled Breath Analysis

The metabolic process of the human body produces a large number of gaseous biomarkers. The tracking and monitoring of certain diseases can be achieved through the detection of these markers. Due to the superior specific surface area, large functional groups, good optical transparency, conductivity and interlayer spacing, graphene, and its derivatives are widely used in gas sensing. Herein, the development of graphene and its derivatives in gas-phase biomarker detection was reviewed in terms of the detection principle and the latest detection methods and applications in several common gases, etc. Finally, we summarized the commonly used materials, preparation methods, response mechanisms for NO, NH₃, H₂S, and volatile organic gas VOCs, and other gas detection, and proposed the challenges and prospective applications in this field.

Frequency of postmortem ethanol formation in blood, urine and vitreous humor - Improving diagnostic accuracy with the use of ethylsulphate and putrefactive alcohols

PURPOSE

This study aimed to compare the frequency of postmortem ethanol formation in blood, urine and vitreous humor according to negative ethylsulphate (EtS) in blood or positive putrefactive alcohols (PA's) in either medium. Furthermore, it aimed to evaluate the interpretational value of calculated ethanol ratios in relation to EtS and PA results.

METHODS

Blood ethanol positive forensic cases were included; one dataset consisting of 2504 cases with EtS analysed in blood and another dataset with 8001 cases where PA's were analysed.

RESULTS

PA's were found in 24.4% of cases. EtS was negative in 15.3%, 9.4% and 7.4% of cases that were positive for ethanol in blood, urine and vitreous humor, respectively. In EtS negative cases, the concentrations of ethanol in blood, urine and vitreous humor were lower than 0.20 g/kg in 51.3%, 67.4% and 77.8%, respectively. It was 1.0 g/kg or higher in blood in 4.2% of cases. More EtS negative and PA positive cases were seen in central compared to peripheral blood. Ethanol ratios between urine or vitreous humor and blood were significantly lower in both EtS negative and PA positive cases, but large variations were observed.

CONCLUSION

EtS and PA analysis improve the diagnostic accuracy of ethanol in postmortem cases. Postmortem ethanol formation in vitreous humor and urine were both more frequent than expected and we recommend the analysis of ethanol primarily in peripheral blood if available.

Evaluation and review of ways to differentiate sources of ethanol in postmortem blood

Accurate determination of a person's blood alcohol concentration (BAC) is an important task in forensic toxicology laboratories because of the existence of statutory limits for driving a motor vehicle and workplace alcohol testing regulations. However, making a correct interpretation of the BAC determined in postmortem (PM) specimens is complicated, owing to the possibility that ethanol was produced in the body after death by the action of various micro-organisms (e.g., Candida species) and fermentation processes. This article reviews various ways to establish the source of ethanol in PM blood, including collection and analysis of alternative specimens (e.g., bile, vitreous humor (VH), and bladder urine), the identification of non-oxidative metabolites of ethanol, ethyl glucuronide (EtG) and ethyl sulfate (EtS), the urinary metabolites of serotonin (5-HTOL/5-HIAA), and identification of n-propanol and n-butanol in blood, which are known putrefaction products. Practical utility of the various biomarkers including specificity and stability is discussed.

Evaluating the hip-flask defence using analytical data from ethanol and ethyl glucuronide. A comparison of two models

AIM

Claimed intake of alcohol after a traffic incident, called the hip-flask defence, can be objectively assessed by different methods. One of them is the use of two consecutive ethanol concentrations in urine and the ratio between ethanol concentrations in urine and blood. Another one is the concentrations of ethyl glucuronide (EtG) and ethyl sulphate (EtS) in blood and their ratio to ethanol. The experimental basis for both these models is from single dose studies only. The aim of this study was therefore to describe the kinetics of ethanol, EtG and EtS after ingestion of two repeated doses of ethanol and to investigate the usefulness of the different models for the assessment of the hip-flask defence.

METHODS

Thirty-five subjects ingested a first dose of 0.51 g of ethanol per kilo body weight, and two hours later a second dose (the hip-flask drink) of 0.25, 0.51 or 0.85 g of ethanol per kilo body weight. Ten urine and 17 blood samples were collected and analysed for ethanol, EtG and EtS using fully validated methods. It was investigated if all subjects fulfilled the criteria for recent drinking, according to the two different models, when using the samples collected 180-240 minutes after start of first dose drinking. According to the first model, increase in urinary ethanol concentrations and a ratio UAC/BAC below 1.3 indicated recent drinking. According to the second model, increase in blood EtG concentrations and a ratio ethanol (g/kg)/EtG (mg/L) above 1 indicated recent drinking.

RESULTS

All subjects in the high dose group fulfilled all criteria for recent drinking. One subject in the medium dose group and nine subjects in the low dose group failed to show increasing UAC and/or a UAC/BAC ratio below 1.3. One subject in the low dose group failed to show increasing concentrations of blood EtG, but all subjects showed a ratio ethanol/EtG above 1.

CONCLUSIONS

The present study showed, by the use of experimental data, that both two models used to investigate the hip-flask defence can be used, but only when the hip-flask dose is sufficiently high.

Epidemiology of alcohol-related unintentional drowning: is post-mortem ethanol production a real challenge?

BACKGROUND

Post-mortem (PM) ethanol production may hamper the interpretation of blood alcohol concentration (BAC) in victims of drowning. Different exclusion criteria (e.g. cases with low BAC or with protracted interval between death and toxicological analysis) have been proposed with no factual figures to reduce the potential bias due to PM ethanol production when examining the prevalence rates for alcohol-related drowning. The aim of this study is to verify the extent to which PM alcohol production may affect the accuracy of studies on drowning and alcohol.

FINDINGS

Unintentional fatal drowning cases (n = 967) for which a full medico-legal autopsy and toxicological analysis was performed, in Finland, from 2000 to 2013, and relevant variables (demographic data of the victims, month of incident, PM submersion time, blood alcohol concentration, urine alcohol concentration (UAC), vitreous humour alcohol concentration (VAC) were available. Overall, out of 967 unintentional drownings, 623 (64.4%) were positive for alcohol (BAC > 0 mg/dL), 595 (61.5%) had a BAC ≥ 50 mg/dL, and 567 (58.6%) a BAC ≥ 100 mg/dL. Simultaneous measurements, in each victim, of BAC, UAC, and VAC revealed PM ethanol production in only 4 victims (BAC: 25 mg/dL - 48 mg/dL). These false positive cases represented 0.4% of drownings with BAC > 0 mg/dL and 14.3% of drownings with BAC > 0 mg/dL and < 50 mg/dL.

CONCLUSIONS

The present study suggests that PM ethanol production has a limited impact on research addressing the prevalence rate for alcohol-related drowning and that the use of too rigorous exclusion criteria, such as those previously recommended, may led to a significant underestimation of actual alcohol-positive drowning cases.

Common Substances of Abuse

Adolescent substance abuse remains common, with almost a third of adolescents admitting to ethanol use, and a quarter admitting to illicit drug use. It is essential for pediatricians to regularly screen adolescent patients for substance use, because early initiation of drug use has been associated with physical, behavioral, and social health risks. Adolescents abuse what is common and readily available; this includes ethanol, over-the-counter products, marijuana, and inhalants. The most common and effective clinical treatments for significant toxicity from substances of abuse is symptomatic and supportive care including hemodynamic support, respiratory support, and sedation to control psychomotor agitation.

Continuous minimally-invasive alcohol monitoring using microneedle sensor arrays

The present work describes an attractive skin-worn microneedle sensing device for the minimally invasive electrochemical monitoring of subcutaneous alcohol. The device consists of an assembly of pyramidal microneedle structures integrated with Pt and Ag wires, each with a microcavity opening. The microneedle aperture was modified by electropolymerizing o-phenylene diamine onto the Pt wire microtransducer, followed by the immobilization of alcohol oxidase (AOx) in an intermediate chitosan layer, along with an outer Nafion layer. The resulting microneedle-based enzyme electrode displays an interference-free ethanol detection in artificial interstitial fluid without compromising its sensitivity, stability and response time. The skin penetration ability and the efficaciousness of the biosensor performance towards subcutaneous alcohol monitoring was substantiated by the ex vivo mice skin model analysis. Our results reveal that the new microneedle sensor holds considerable promise for continuous non-invasive alcohol monitoring in real-life situations.

An overview on forensic analysis devoted to analytical chemists

The present article has as main aim to show analytical chemists interested in forensic analysis the world they will face if decision in favor of being a forensic analytical chemist is adopted. With this purpose, the most outstanding aspects of forensic analysis in dealing with sampling (involving both bodily and no bodily samples), sample preparation, and analytical equipment used in detection, identification and quantitation of key sample components are critically discussed. The role of the great omics in forensic analysis, and the growing role of the youngest of the great omics -metabolomics- are also discussed. The foreseeable role of integrative omics is also outlined.

Auto-brewery syndrome: Ethanol pseudo-toxicity in diabetic and hepatic patients

Endogenous alcohol has been applied for spontaneous ethanol production via different metabolic pathways of the human body. Auto-brewery syndrome describes the patients with alcohol intoxication after ingesting carbohydrate-rich meals. The main objective of this study is to investigate the effect of diabetes mellitus (DM), liver cirrhosis (LC) and presence of both (DM and LC) on blood alcohol concentration (BAC) especially after carbohydrate ingestion. BAC has been measured by headspace gas chromatography-mass spectrometry in three groups of humans namely control, DM, LC and both (DM and LC) groups. The results showed that BAC in control group was 0.01-.3 mg/dL with mean 0.3 ± 0.41 mg/dL. In patients with DM, BAC is significantly higher than that of control group 4.85 ± 3.96 mg/dL. In patients with LC, BAC was 3.45 ± 2.65 mg/dL. In patients with both DM and LC, BAC increases to reach 10.88 ± 5.36 mg/dL. Endogenous ethanol production appears to increase in DM and LC. Also, it increased much more in patients with both diseases, but it did not reach toxic levels. On comparing BAC and blood glucose level in each group, all groups show insignificant correlations ( p > 0.05).

Cause and manner of death and phase of the blood alcohol curve

In a large number of forensic autopsies (N = 28,184) the concentrations of ethanol in femoral blood and bladder urine were determined and the urine-to-blood concentration ratios of ethanol were calculated. Based on the differences in ethanol concentration between urine and blood, the deaths were classified as having occurred during the absorptive, the peak or the post-absorptive phase of the blood–alcohol curve. Most people died in the post-absorptive phase, N = 24,223 (86%), whereas 1538 individuals (5.5%) were still absorbing alcohol and 2423 (8.6%) were at or close to the peak BAC at time of death. Both blood–alcohol concentration (BAC) and urine–alcohol concentration (UAC) were significantly higher in the post-absorptive phase (p < 0.001). The proportions of people dying in the absorptive and peak phases increased with advancing age. The cause of death (CoD) and manner of death (MoD) according to death certificates were compared with phase of the blood–alcohol curve using a multinomial regression model with and without making adjustment for possible effects of age, gender and BAC. The relative risk (RR) and relative risk ratios (RRR) showed some associations between CoD and phase of the blood–alcohol curve. Undetermined MoD was significantly higher in the absorptive phase compared with the post-absorptive phase (RRR = 2.12). Deaths related to esophagus, stomach and duodenum (RRR = 2.04) and alcoholic liver diseases (RRR = 1.85) were significantly higher at or close to peak phase compared to the post-absorptive phase. Road-traffic fatalities were more prevalent in the peak BAC phase (RRR = 1.33) and deaths by accidental falls were less in the absorptive phase (RRR = 0.58) compared with the post-absorptive phase. The phase of alcohol intoxication seems relevant to consider by forensic experts when alcohol-related deaths are investigated.

Postmortem Ethanol Concentrations and Postmortem Ethanol Production

A review of the literature was conducted in reference to postmortem blood ethanol concentrations and the issue of postmortem production of ethanol. Ethanol in postmortem specimens may occur as a result of antemortem consumption (most common), postmortem production in the body or in vitro by microorganisms (less common), and endogenous production by microorganisms during life (rare). The portion of ethanol-positive postmortem cases in which postmortem production of ethanol is thought to have occurred is small, as is the portion of cases in which postmortem production of ethanol is a potentially important issue. It is unusual for postmortem production of ethanol to account for more than a 70 mg/dL concentration, but cases with higher concentrations occasionally occur. Cases in which blood ethanol is positive but vitreous ethanol concentration is much lower or negative, and/or in which the urine: blood ethanol concentration ratio is less than one are supportive of postmortem ethanol production. The presence of other alcohols such as n-propanol and/or n-butanol is suggestive of postmortem microbial production of ethanol. The ratio of serotonin metabolites in urine may be helpful in distinguishing postmortem production of ethanol from antemortem consumption, as may the concentration of ethyl glucuronide in blood. Candida and some other species may produce ethanol in urine antemortem and postmortem. In rare instances such as infections, endogenous ethanol production may occur in a living person. Recommendations are made concerning samples to collect and tests that may be helpful in distinguishing antemortem ethanol consumption from postmortem production of ethanol.

Sources of variability in biomarker concentrations

Human biomonitoring has become a primary tool for chemical exposure characterization in a wide variety of contexts: population monitoring and characterization at a national level, assessment and description of cohort exposures, and individual exposure assessments in the context of epidemiological research into potential adverse health effects of chemical exposures. The accurate use of biomonitoring as an exposure characterization tool requires understanding of factors, apart from external exposure level, that influence variation in biomarker concentrations. This review provides an overview of factors that might influence inter- and intraindividual variation in biomarker concentrations apart from external exposure magnitude. These factors include characteristics of the specific chemical of interest, characteristics of the likely route(s) and frequency of exposure, and physiological characteristics of the biomonitoring matrix (typically, blood or urine). Intraindividual variation in biomarker concentrations may be markedly affected by the relationship between the elimination half-life and the intervals between exposure events, as well as by variation in characteristics of the biomonitored media such as blood lipid content or urinary flow rate. Variation across individuals may occur due to differences in time of sampling relative to exposure events, physiological differences influencing urinary flow or creatinine excretion rates or blood characteristics, and interindividual differences in metabolic rate or other factors influencing the absorption or excretion rate of a compound. Awareness of these factors can assist researchers in improving the design and interpretation of biomonitoring studies.

Toxicology, circumstances and pathology of deaths from acute alcohol toxicity

Alcohol consumption makes a large contribution to premature mortality. In order to extend our understanding of the characteristics, circumstances, toxicology and pathology of alcohol toxicity deaths, all cases presenting to the Department of Forensic Medicine Sydney between 1/1/1997-31/12/2011 with blood alcohol concentrations (BACs) ≥0.300 g/100 ml and where the direct cause of death was acute alcohol toxicity were retrieved (n = 83). The mean age was 47.2 yrs and 77.1% were male. The majority (81.9%) of deaths occurred in a home environment, and did not vary across month or day of the week. In 91.6% of cases, a history of alcoholism or heavy alcohol consumption was reported. None were in any form of substance dependence treatment at the time of death. The mean BAC was 0.420 g/100 ml (range 0.300-0.741 g/100 ml). In 33.7% of cases, other substances were detected, predominantly diazepam (28.9%). BACs did not vary significantly by gender, age or BMI. Urine/BAC ratios of >1.25 were seen in 6/43 cases where both samples were available. Cardiac disease was noted in 75.9% of cases and hepatic disease in 91.6%. The only alcohol-related organic brain syndrome pathology identified at autopsy was vermal cerebellar degeneration.

Collection of biological samples in forensic toxicology

Forensic toxicology is the study and practice of the application of toxicology to the purposes of the law. The relevance of any finding is determined, in the first instance, by the nature and integrity of the specimen(s) submitted for analysis. This means that there are several specific challenges to select and collect specimens for ante-mortem and post-mortem toxicology investigation. Post-mortem specimens may be numerous and can endow some special difficulties compared to clinical specimens, namely those resulting from autolytic and putrefactive changes. Storage stability is also an important issue to be considered during the pre-analytic phase, since its consideration should facilitate the assessment of sample quality and the analytical result obtained from that sample. The knowledge on degradation mechanisms and methods to increase storage stability may enable the forensic toxicologist to circumvent possible difficulties. Therefore, advantages and limitations of specimen preservation procedures are thoroughfully discussed in this review. Presently, harmonized protocols for sampling in suspected intoxications would have obvious utility. In the present article an overview is given on sampling procedures for routinely collected specimens as well as on alternative specimens that may provide additional information on the route and timing of exposure to a specific xenobiotic. Last, but not least, a discussion on possible bias that can influence the interpretation of toxicological results is provided. This comprehensive review article is intented as a significant help for forensic toxicologists to accomplish their frequently overwhelming mission.

A review of the use of ethyl glucuronide as a marker for ethanol consumption in forensic and clinical medicine

Ethyl glucuronide (EtG) is a direct phase-II metabolite of ethanol formed through the UDP-glucuronosyl transferase catalyzed conjugation of ethanol with glucuronic acid. It has been detected in many antemortem and postmortem biological matrices using a variety of analytical methods. Due to its long urinary elimination time, detectability in hair, specificity for ethanol exposure, and low detection limits of assays, the use of EtG has been proposed as a marker of recent ethanol intake in a variety of clinical and legal settings, including medical monitoring for relapse, emergency department patient evaluation, postmortem assessments, and transportation accident investigation. However, challenges associated with factors such as establishing appropriate cut-off levels capable of distinguishing between drinking and nonbeverage sources of ethanol exposure, nonuniform laboratory reporting limits, sample stability, and microbial activity substantially complicate accurate interpretation of results. The following review briefly explores the history, utility, and limitations of EtG in contemporary medical and forensic practice.

Comparison of extraction efficiencies and LC-MS-MS matrix effects using LLE and SPE methods for 19 antipsychotics in human blood

Antipsychotic drugs are frequently associated with sudden death investigations. Detection of these drugs is necessary to establish their use and possible contribution to the death. LC-MS(MS) methods are common; however accurate and precise quantification is assured by using validated methods. This study compared extraction efficiency and matrix effects using common liquid-liquid and solid-phase extraction procedures in both ante-mortem and post-mortem specimen using LC-MS-MS. Extraction efficiencies and matrix effects were determined in five different blank blood specimens of each blood type. The samples were extracted using a number of different liquid-liquid extraction methods and compared with a standard mixed-mode solid-phase extraction method. Matrix effects were determined using a post-extraction addition approach-the blank blood specimens were extracted as described above and the extracts were reconstituted in mobile phase containing a known amount of analytes. The extraction comparison of ante-mortem and post-mortem blood showed considerable differences, in particular the extraction efficiency was quite different between ante-mortem and post-mortem blood. Quantitative methods used for determination of antipsychotic drugs in post-mortem blood should establish that there are no differences in extraction efficiency and matrix effects, particularly if using ante-mortem blood as calibrator.

Urine drug screening: practical guide for clinicians

Drug testing, commonly used in health care, workplace, and criminal settings, has become widespread during the past decade. Urine drug screens have been the most common method for analysis because of ease of sampling. The simplicity of use and access to rapid results have increased demand for and use of immunoassays; however, these assays are not perfect. False-positive results of immunoassays can lead to serious medical or social consequences if results are not confirmed by secondary analysis, such as gas chromatography-mass spectrometry. The Department of Health and Human Services' guidelines for the workplace require testing for the following 5 substances: amphetamines, cannabinoids, cocaine, opiates, and phencyclidine. This article discusses potential false-positive results and false-negative results that occur with immunoassays of these substances and with alcohol, benzodiazepines, and tricyclic antidepressants. Other pitfalls, such as adulteration, substitution, and dilution of urine samples, are discussed. Pragmatic concepts summarized in this article should minimize the potential risks of misinterpreting urine drug screens.

A pharmacokinetic study of ethyl glucuronide in blood and urine: Applications to forensic toxicology

This pharmacokinetic study investigated the kinetics of ethanol and its metabolite ethyl glucuronide (EtG) in blood and urine during the whole time course of absorption and elimination. There are few previous studies on the kinetics of EtG in blood, and we wanted to evaluate whether such knowledge could yield valuable information regarding the time of ethanol ingestion in forensic cases, such as, for instance, drunk driving. Ten male volunteers consumed ethanol at a fixed dose of 0.5 g/kg body weight in a fasted state. Blood samples were collected for 14 h and urine samples were collected for 45-50 h after the start of drinking. EtG reached its maximum concentration (C(max)) in blood after a median of 4 h (range 3.5-5), a median of 3 h (range 2-4.5) after C(max) for ethanol. The ethanol-to-EtG ratios in blood (ethanol in g/L, EtG in mg/L) were >1 only for the first median 3.5 h (range 2.5-3.5) after drinking. EtG elimination occurred with a median half-life of 2.2 h (range 1.7-3.1 h), and the renal clearance was 8.32 L/h (median, range 5.25-20.86). The concentrations of EtG were always much higher in urine than in blood. The total amount of EtG excreted in the urine was median 30 mg (range 21.5-39.7), representing 0.017% (median, range 0.013-0.022) of the ethanol given, on a molar basis. The information from the present study may be a valuable supplement to determine the time of ethanol ingestion. For this purpose, two subsequent increasing EtG values and a high ethanol-to-EtG ratio in blood would support information of recent drinking.

Alcohol biomarker analysis: simultaneous determination of 5-hydroxytryptophol glucuronide and 5-hydroxyindoleacetic acid by direct injection of urine using ultra-performance liquid chromatography-tandem mass spectrometry

A direct ultra-performance liquid chromatography-tandem mass spectrometry method (UPLC-MS/MS) for simultaneous measurement of urinary 5-hydroxytryptophol glucuronide (GTOL) and 5-hydroxyindoleacetic acid (5-HIAA) was developed. The GTOL/5-HIAA ratio is used as an alcohol biomarker with clinical and forensic applications. The method involved dilution of the urine sample with deuterated analogues (internal standards), reversed-phase chromatography with gradient elution, electrospray ionisation and monitoring of two product ions per analyte in selected reaction monitoring mode. The measuring ranges were 6.7-10 000 nmol/l for GTOL and 0.07-100 micromol/l for 5-HIAA. The intra- and inter-assay imprecision, expressed as the coefficient of variation, was below 7%. Influence from ion suppression was noted for both compounds but was compensated for by the use of co-eluting internal standards. The accuracy in analytical recovery of added substance to urine samples was 96 and 98%, respectively, for GTOL and 5-HIAA. Method comparison with GC-MS for GTOL in 25 authentic patient samples confirmed the accuracy of the method with a median ratio between methods (GC-MS to UPLC-MS/MS) of 1.14 (r(2) = 0.975). The difference is explained by the fact that the GC-MS method also measures unconjugated 5-hydroxytryptophol naturally present in urine. The comparison with data for 5-HIAA obtained by an HPLC method demonstrated a median ratio of 1.05 between the methods. The UPLC-MS/MS method was capable of measuring endogenous GTOL and 5-HIAA levels in urine, which agreed with the literature data. In conclusion, a fully validated and robust direct method for the routine measurement of urinary GTOL and 5-HIAA was developed.

Role of Myocardial Contractility and Autonomic Control in the Hypotensive Response to a Limited Access Ethanol Paradigm in SHRs

BACKGROUND

Previous experimental studies that evaluated the chronic hemodynamic effect of ethanol employed the continuous exposure protocol of ethanol, which does not mimic the pattern of alcohol consumption in humans. This study dealt with the long-term hemodynamic and cardiovascular autonomic effects of ethanol, in a limited-access regimen in telemetered spontaneously hypertensive rats (SHRs).

METHODS

Changes in blood pressure (BP), heart rate (HR), myocardial contractility (dP/dt(max)), and spectral cardiovascular autonomic profiles during the ethanol exposure period (2.5 or 5% w/v, 8 h/d, 8:30 am till 4:30 pm) were followed for 12 weeks.

RESULTS

Compared with control pair-fed SHRs, body weight and urine output, osmolality, and potassium levels were decreased in SHRs receiving 5% but not 2.5% ethanol. Blood pressure showed progressive falls during ethanol-feeding periods with a maximum effect observed at week 5. The peak hypotensive effect was maintained thereafter in SHRs receiving 5% ethanol in contrast to steady rises in BP in the 2.5% ethanol group to near-control levels by the conclusion of the study. Heart rate was slightly but significantly increased by ethanol 5% whereas dP/dt(max) showed persistent reductions. Power spectral analysis showed that ethanol attenuated the baroreflex gain of HR as suggested by the reductions in index alpha, the spectral index of spontaneous baroreflex sensitivity (BRS).

CONCLUSIONS

It is concluded that limited access ethanol drinking in SHRs elicited hypotension that was concentration dependent and mediated, at least partly, through reductions in myocardial contractility. Baroreflex sensitivity attenuation by ethanol appeared to have limited the tachycardic response to ethanol and perhaps its capacity to offset the evoked hypotension.