The ratio of blood-alcohol concentration (BAC) to breath-alcohol concentration (BrAC), which is commonly referred to as the blood/breath ratio (BBR), is an important concept in forensic science and legal medicine. For example, the BBR serves as the calibration factor used when a breath-alcohol test result is converted into the coexisting BAC for clinical, research, and forensic purposes. Furthermore, when legislative bodies established statutory BrAC limits for driving, they divided the statutory BAC limit by an assumed population average BBR, hence BrAC = BAC/BBR. However, jurisdictions opted to use different BBRs when calculating statutory BrAC limits for driving, and values of 2000:1, 2100:1, 2300:1, and 2400:1 were used in different countries. Under in vitro conditions, the blood/air partition ratio of ethanol can be determined with high precision (coefficient of variation CV ~2%), whereas in vivo the BBR of alcohol depends on numerous physiological factors, such as lung physiology, breathing pattern, and other biological variables; BBRs in vivo have CVs ranging from 8-12%, depending on the type of breath analyzer used. BrAC increases during a prolonged exhalation into an evidential breath-alcohol analyzer and the BBR therefore decreases as a person reaches a vital capacity exhalation. The BBR of alcohol also depends on whether arterial (A) or venous (V) blood samples were used for ethanol analysis, because A-V differences are continuously changing during the absorption, distribution, and elimination stages of the blood-alcohol curve. This article reviews the historical background and wisdom of assuming a constant BBR of alcohol for legal purposes when breath test results are used as a proxy for venous BAC. Discussion and debate about a person's BBR should be irrelevant in those jurisdictions that enforce a statutory BrAC limit for driving.

This article traces the development and present status of legislation pertaining to driving under the influence of alcohol (DUI) and other drugs (DUID) in the United Kingdom (UK). The Road Safety Act of 1967 represented a paradigm shift in the way that traffic offenders were prosecuted for driving after consumption of alcohol. This new legislation defined punishable concentrations of alcohol (ethanol) in samples of the driver’s blood (80 mg%) or urine (107 mg%). The creation of these statutory concentration limits meant that it was no longer necessary to prove that a suspect was under the influence or impaired by alcohol at the time of driving. Also in 1967, a police officer in uniform was permitted to administer a roadside breath alcohol screening test to help make a decision whether a suspect should be arrested for further investigation. In 1983, the British government introduced a statutory breath alcohol concentration limit of 35 µg/100 mL and evidential quality breath analyzers were approved for use by the police as an alternative to sampling blood or urine for analysis. Evidence of driving under the influence of drugs other than alcohol depended on the results of a clinical examination and questionnaire done by a police surgeon. This was supported by evidence presented by the arresting police officers or other witnesses. In 2015, a radical change occurred in the legislation pertaining to drug-impaired driving where instead of relying on clinical evidence of impairment, concentration limits in blood for 17 psychoactive substances were defined by statute. These consisted of eight commonly encountered recreational drugs of abuse and nine prescription medications (opiates and benzodiazepines), all classified as controlled substances.

Forensic science is a multidisciplinary field that involves the use of various scientific methods and techniques for the investigation of crimes. Forensic scientists are often required to testify in court as expert witnesses and explain the meaning of chemical, physical, and/or medical evidence to a judge and jury. This article took advantage of a citation database to identify the most highly cited forensic practitioners in four Nordic countries within the discipline of legal and forensic medicine. The starting point was 7 million scientists indexed in the SCOPUS database, each of whom had their name on at least five entries. Six different citation metrics were used to calculate a person’s composite citation score. Those within the top 2% of their primary research discipline were considered highly cited.

Soon approaching its 50th anniversary, Journal of Analytical Toxicology (JAT) is an international scholarly publication specializing in analytical and forensic aspects of toxicology. Science Citation Index (SCI) and Journal Citation Reports (JCR), both of which are part of the Web-of-Science (WOS) database, were used to make a bibliometric evaluation of JAT articles. Between 1977 (volume 1) and 2023 (volume 47), a total of n = 4,785 items were published in JAT; the top-ten most highly cited articles and the most prolific authors were identified. Changes in the journal impact factor (JIF) were studied between 1997 and 2022, and this metric varied from a low of 1.24 (2006) to a high of 3.36 (2020).The most recent JIF (2022) dropped to 2.5 and the corresponding 5 year JIF was 2.6. JATs most highly cited article (590 cites) was a working group (SWGTOX) report dealing with standard practices for the validation of analytical methods in forensic toxicology laboratories. JAT published 62 articles each of which were cited over 100 times and the H-index for JAT was 89. The most prolific author of JAT articles was credited with 119 items, the first in 1980 (volume 4) and the latest in 2023 (volume 47). JAT articles were cited 4,537 times in 2022 by all journals in the JCR database, although 520 of these were self-citations (11.5%). Bibliometric methods are increasingly used to evaluate the published work of individual scientists, university departments, entire universities and whole countries. Highly cited articles are considered more influential and authoritative compared with papers that are seldom or never cited.

This article traces the historical development of various biomarkers of acute and/or chronic alcohol consumption. Much of the research in this domain of clinical and laboratory medicine arose from clinics and laboratories in Sweden, as exemplified by carbohydrate deficient transferrin (CDT) and phosphatidylethanol (PEth). Extensive studies of other alcohol biomarkers, such as ethyl glucuronide (EtG), ethyl sulfate (EtS), and 5-hydroxytryptophol (5-HTOL), also derive from Sweden. The most obvious test of recent drinking is identification of ethanol in a sample of the persons blood, breath, or urine. However, because of continuous metabolism in the liver, ethanol is eliminated from the blood at a rate of 0.15 g/L/h (range 0.1-0.3 g/L/h), so obtaining positive results is not always possible. The widow of detection is increased by analysis of ethanols non-oxidative metabolites (EtG and EtS), which are more slowly eliminated from the bloodstream. Likewise, an elevated ratio of serotonin metabolites in urine (5-HTOL/5-HIAA) can help to disclose recent drinking after ethanol is no longer measurable in body fluids. A highly specific biomarker of hazardous drinking is CDT, a serum glycoprotein (transferrin), with a deficiency in its N-linked glycosylation. Another widely acclaimed biomarker is PEth, an abnormal phospholipid synthesized in cell membranes when people drink excessively, having a long elimination half-life (median similar to 6 days) during abstinence. Research on the subject of alcohol biomarkers has increased appreciably and is now an important area of drug testing and analysis.

This technical note reviews the plethora of concentration units used to report blood-alcohol concentration (BAC) and breath-alcohol concentrations (BrAC) for legal purposes in different countries. The choice of units sometimes causes confusion when scientific papers originating from a certain country might be introduced into evidence via expert testimony, such as when alcohol-related crimes are prosecuted. The concentration units are also important to consider when blood/breath ratios (BBRs) of alcohol are calculated and compared between countries. Statutory BAC limits for driving in most nations are reported in mass/volume (m/v) units, such as g/100 mL (g%) in the United States, mg/100 mL (mg%) in the United Kingdom and Republic of Ireland, or g/L (mg/mL) in many EU nations. By contrast, Germany and the Nordic countries report BAC as mass/mass (m/m) units, hence g/kg or mg/g, which are similar to 5.5% lower than m/v units, because whole blood has an average density of 1.055 g/mL. There are historical reasons for reporting BAC in mass/mass units because the aliquots of blood analyzed were measured by weight rather than volume. The difference between m/m and m/v is also important in postmortem toxicology, such as when distribution ratios of ethanol between blood and other biological specimens, such as urine, vitreous humor, and cerebrospinal fluid, are reported.

This article traces the origin of various charts and tables delineating the stages of alcohol influence in relation to the clinical signs and symptoms of drunkenness and a person's blood-alcohol concentration (BAC). In forensic science and legal medicine, the most widely used such table was created by Professor Kurt M. Dubowski (University of Oklahoma). The first version of the Dubowski alcohol table was published in 1957, and minor modifications appeared in various articles and book chapters until the final version was published in 2012. Seven stages of alcohol influence were identified including subclinical (sobriety), euphoria, excitement, confusion, stupor, alcoholic coma and death. The BAC causing death was initially reported as 0.45+ g%, although the latest version cited a mean and median BAC of 0.36 g% with a 90% range from 0.21 g% to 0.50 g%. An important feature of the Dubowski alcohol table was the overlapping ranges of BAC for each of the stages of alcohol influence. This was done to reflect variations in the physiological effects of ethanol on the nervous system between different individuals. Information gleaned from the Dubowski table is not intended to apply to any specific individual but more generally for a population of social drinkers, not regular heavy drinkers or alcoholics. Under real-world conditions, much will depend on a person's age, race, gender, pattern of drinking, habituation to alcohol and the development of central nervous tolerance. The impairment effects of ethanol also depend to some extent on whether observations are made on the rising or declining phase of the blood-alcohol curve (Mellanby effect). There will always be some individuals who do not exhibit the expected behavioral impairment effects of ethanol, such as regular heavy drinkers and those suffering from an alcohol use disorder.

Many people convicted for drunken driving suffer from an alcohol use disorder and some traffic offenders consume denatured alcohol for intoxication purposes. Venous blood samples from people arrested for driving under the influence of alcohol were analyzed in triplicate by headspace gas chromatography (HS-GC) using three different stationary phases. The gas chromatograms from this analysis sometimes showed peaks with retention times corresponding to acetone, ethyl methyl ketone (2-butanone), 2-propanol, and 2-butanol in addition to ethanol and the internal standard (1-propanol). Further investigations showed that these drink-driving suspects had consumed an industrial alcohol (T-Red) for intoxication purposes, which contained > 90% w/v ethanol, acetone (similar to 2% w/v), 2-butanone (similar to 5% w/v) as well as Bitrex to impart a bitter taste. In n = 75 blood samples from drinkers of T-Red, median concentrations of ethanol, acetone, 2-butanone, 2-propanol and 2-butanol were 2050 mg/L (2.05 g/L), 97 mg/L, 48 mg/L, 26 mg/L and 20 mg/L, respectively. In a separate GC analysis, 2,3-butanediol (median concentration 87 mg/L) was identified in blood samples containing 2-butanone. When the redox state of the liver is shifted to a more reduced potential (excess NADH), which occurs during metabolism of ethanol, this favors the reduction of low molecular ketones into secondary alcohols via the alcohol dehydrogenase (ADH) pathway. Routine toxicological analysis of blood samples from apprehended drivers gave the opportunity to study metabolism of acetone and 2-butanone without having to administer these substances to human volunteers.

Historical events leading to the development of the first handheld instrument for breath alcohol analysis using an electrochemical sensor are reviewed. The first prototype instrument, known as the Alcolmeter Pocket Model, became available in 1972 and weighed only 180 g and was about the size of a cellphone. By the mid-1970s, the Alcolmeter instrument was used by police forces in several countries as a preliminary roadside test of driver sobriety. Positive results in a roadside breath test were considered sufficient evidence to arrest a suspect for further evaluation and testing. This might entail an evidential-quality breath alcohol test or taking a sample of the driver's blood for analysis at a forensic laboratory. The main advantages of breath testing over blood testing are the non-invasive nature of the sampling procedure compared with sticking a needle in a vein to draw blood, and obtaining immediate information whether or not a person is in breach of the drunk driving legislation.