Elevated blood-ethanol concentration promotes reduction of aliphatic ketones (acetone and ethyl methyl ketone) to secondary alcohols along with slower oxidation to aliphatic diols.

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 (~ 2% w/v), 2-butanone (~ 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.

Post-mortem formation of ethanol: Is 1-propanol a reliable marker? A proof-of-concept study using an in vitro putrefactive environment setup.

Ethanol is the psychoactive substance identified most frequently in post-mortem specimens. Unfortunately, interpreting post-mortem ethanol concentrations can be difficult because of post-mortem alcohol redistribution and the possibility of post-mortem alcohol neogenesis. Indeed, in the time interval between death and sample collection, the decedent may be exposed to non-controlled environments for an extended period, promoting microbial colonization. Many authors report that in the presence of carbohydrates and other biomolecules, various species of bacteria, yeast, and fungi can synthesize ethanol and other volatile substances in vitro and in vivo. The aim of this study was to study the impact of several variables on microbial ethanol production as well as develop a mathematical model that could estimate the microbial-produced ethanol in correlation with the most significant consensual produced higher alcohol, 1-propanol. An experimental setup was developed using human blood samples and cadaveric fragments incubated under strictly anaerobic conditions to produce a novel substrate, "cadaveric putrefactive blood" mimicking post-mortem corpse conditions. The samples were analyzed daily for ethanol and 1-propanol using an HS-GC-FID validated method. The formation of ethanol was evaluated considering different parameters such as putrefactive stage, blood glucose concentration, storage temperature, and storage time. Statistical analysis was performed using the Mann-Whitney non-parametric test and simple linear regression. The results indicate that the early putrefactive stage, high blood glucose concentration, high temperature, and time of incubation increase microbial ethanol production. In addition, the developed mathematical equation confirms the feasibility of using 1-propanol as a marker of post-mortem ethanol production.

Ethanol stability in unpreserved refrigerated antemortem blood.

Ethanol stability in preserved antemortem blood has been widely studied since it is a common practice in cases involving suspected impaired driving to collect antemortem blood in evacuated blood tubes containing sodium fluoride. In some situations, antemortem blood is submitted to a forensic laboratory for ethanol analysis in evacuated blood tubes that contain only an anticoagulant. There has been limited research on ethanol stability in antemortem blood stored without a preservative. On two occasions, antemortem blood was collected from five ethanol-free individuals into 6-ml Vacutainer® tubes containing only 10.8 mg potassium EDTA. The blood tubes were spiked with ethanol to approximately either 0.08 or 0.15 g/dl. Dual-FID headspace gas chromatography was used to analyze 58 blood tubes, 29 from each session, for ethanol 1 day after sample collection and again after 1 year of refrigerated storage (~4°C). Statistically significant decreases in ethanol were detected at the 0.05 level of significance. Mean decreases in ethanol after 1 year of storage for the 0.08 and 0.15 g/dl samples were 0.013 and 0.010 g/dl, respectively. The mean ethanol decrease across all tubes was 0.012 g/dl. The range of decreases for the 58 blood tubes was 0.003-0.018 g/dl. The mean ethanol decreases measured in this unpreserved antemortem blood are comparable in magnitude to those previously observed in antemortem blood containing sodium fluoride after 1 year of refrigerated storage. Ethanol did not increase in the antemortem blood samples despite the absence of sodium fluoride.

Statistical comparisons of 0.08 g/100 ml fortified blood alcohol samples from 6-ml and 10-ml gray-top tubes.

This experiment supplements the study, "Statistical comparisons of blood alcohol samples from 6-ml and 10-ml grey-top tubes". The initial study analyzed fortified samples for blood alcohol concentration (BAC) using two sizes of gray-top tubes: a 10-ml tube containing a nominal 1% sodium fluoride (NaF), a preservative, and a 6-ml tube containing 0.25% NaF, using the variables of time, storage temperature, fill volume, and concentration. From that study, paired t-tests determined no difference in BAC from data sets of the two tube sizes, however, Analysis of Variance, or ANOVA, testing determined the two tube sizes yielded different results at 0.08 g/100 ml. To investigate this potential disparity, this study fortified new samples at 0.08 g/100 and focused on two variables: fill volume and storage duration, while increasing the sample population (to n = 8). For this study, the two tube types yielded equivalent concentrations under the majority of conditions studied. Differences between the two tube types were found using paired t-test for the high-volume samples on Days 7 and 30; ANOVA yielded the same results but also determined one additional statistical difference for the Day 30 low-volume samples. However, the differences observed between tube sizes fall within standard deviation ranges established for the analytical method precision profile, indicating statistical differences are not analytically significant. Further studies are needed to investigate the comparability of the tubes under real-world conditions, under which oxygen and/or additives are not added during sample preparation steps or by usage of blood bank products.

Lack of fermentation in antemortem blood samples stored unstoppered in various locations.

A common defense challenge when antemortem blood ethanol results are presented at trial is the assertion that ethanol was formed in the blood tube after the blood draw through fermentation of the blood glucose by Candida albicans (C. Albicans). In contrast, decades of research into the stability of ethanol in antemortem blood collected for forensic purposes have consistently shown that any analytically significant change in ethanol concentration is a decrease and initially, ethanol-negative blood remains ethanol-negative with storage. For there to be any possibility of fermentation to occur by C. Albicans in an antemortem blood sample there must be a plausible mechanism for introduction of C. Albicans into the blood. One mechanism proffered at trial is environmental contamination resulting from ambient air drawn into the evacuated blood collection tube. Blood was drawn from ethanol-free individuals into 6 and 10-ml gray-top Vacutainer® tubes containing sodium fluoride and 6-ml Vacutainer® tubes without a preservative. Following the blood draws, the tubes were stored unstoppered at room temperature for 24 or 48 h in various locations. Following unstoppered storage, the tubes were stoppered and stored refrigerated (~4°C), left at room temperature (~22°C), or placed in an oven (37°C). The refrigerated blood was analyzed for ethanol using headspace gas chromatography after both 5 days and 32 months. Unrefrigerated blood samples were analyzed after being stored at room temperature or in an oven for up to 30 days. Ethanol was not detected in any of the blood tubes after storage regardless of storage time, storage temperature, or preservative concentration.

Sex differences in alcohol dehydrogenase levels (ADH) and blood ethanol concentration (BEC) in Japanese quail.

Ethanol is one of the most widely used and abused drugs. Following ethanol consumption, ethanol enters the bloodstream from the small intestine where it gets distributed to peripheral tissues. In the bloodstream, ethanol is cleared from the system by the liver. The primary metabolism of ethanol uses alcohol dehydrogenase (ADH). In mammals, females appear to have higher ADH activity in liver samples than males. The purpose of the first experiment was to analyze sex differences in ADH levels following 12 d of ethanol administration (i.e., water or 2 g/kg) in male and female quail. Following the last daily treatment of ethanol, quail were euthanized, their livers were extracted, and ADH was analyzed in liver homogenate samples. Results showed that female quail had higher ADH levels, heavier livers, and a greater liver to body weight ratio than male quail. In a second experiment, we aimed to develop a blood ethanol concentration (BEC) profile for both male and female quail. Quail were administered 0.75 or 2 g/kg of ethanol and blood was collected at 0.5, 1, 2, 4, 6, 8, 12, 24 h after gavage administration. Blood ethanol concentration was analyzed using an Analox. We found that quail had a fairly rapid increase in BECs followed by a steady and slow disappearance of ethanol from the blood samples. Female quail had a lower peak of ethanol concentration and a smaller area under the curve (AUC) than male quail. The current research suggests that higher ADH levels in female quail may be responsible for increased metabolism of ethanol. In general, quail appear to eliminate ethanol more slowly than rodents. Thus, as a model, they may allow for a prolonged window with which to investigate the effects of ethanol.

Testing antemortem blood samples for ethanol after four to seven years of refrigerated storage.

The previous studies on ethanol stability in antemortem blood samples stored under various conditions have shown that ethanol concentration decreases with storage. The feasibility of measuring a forensically meaningful blood ethanol concentration in antemortem blood samples stored refrigerated (~4°C) from 4-7 years after the blood draw was evaluated in this research. All blood samples were collected into two 10-ml gray top Vacutainer® tubes as part of police driving under the influence investigations. In 29 cases, blood in the tube originally analyzed was retested after 5-7 years of refrigerated storage. Blood in 41 cases was analyzed in a previously unopened blood tube from the case after 4-7 years of refrigerated storage. The first analysis of blood in each case occurred within 35 days of the blood draw. Initial blood ethanol concentrations ranged from 0.094 g/dl to 0.301 g/dl. No samples showed an increase in ethanol concentration with storage that exceeded the uncertainty of the initial measurement. All decreases in ethanol concentration were less than 0.020 g/dl. The mean differences in ethanol concentration in previously opened and unopened tubes were -0.014 g/dl and -0.010 g/dl, respectively. The results of this research support that antemortem blood in previously opened and unopened refrigerated blood tubes can be analyzed for ethanol content more than 4 years and as much as 7 years after the blood draw and provide a result consistent with the amount of ethanol loss expected from a test done within 1-3 years of the blood draw.

Large-scale reanalysis of refrigerated antemortem blood samples for ethanol content at random intervals.

Ethanol stability in antemortem blood stored under various conditions has been widely studied. Most such studies have somewhat limited sample size (<50) and limited variation in the length of time between the blood draw and the first analysis and between the first analysis and the reanalysis. In the work presented here, the antemortem blood drawn for forensic purposes and stored refrigerated (~4°C) in 371 cases was analyzed for ethanol concentration using headspace gas chromatography at various times after the blood draw based on routine case flow and then also analyzed at various times within approximately 1 year after the first analysis. This methodology is intended to provide insight into the range of differences expected when cases are analyzed in the normal flow of casework and then reanalyzed at random times afterwards as occurs when reanalysis is performed by the defense or by the laboratory if the original analyst is unavailable to testify. In 22 cases, the same blood tube from the case was reanalyzed. The previously unopened blood tube from the case was analyzed in 349 cases. The 25 cases in which the blood was ethanol-negative based on the first analysis remained ethanol-negative when reanalyzed. The average difference in ethanol concentration between tests for the ethanol-positive cases was -0.004 g/dL. This decrease was statistically significant at the 0.05 level of significance. The range of differences was -0.0197 to 0.0103 g/dL. The difference measured in 85% of the ethanol-positive cases was in in the range of -0.008 to -0.001 g/dL.

Isobutylene contamination of blood collected in 10-ml evacuated blood collection tubes with gray conventional rubber stoppers.

Dual-column headspace gas chromatographic analysis with two flame-ionization detectors is a commonly used analytical technique for forensic blood ethanol quantitation. This technique is also applicable to the identification and quantitation of other volatile organic compounds such as methanol in biological samples. Compound identification by retention time is limited to those compounds with known retention times programmed into the instrument method. Historically, an early-eluting peak from an unidentified compound has been observed in both chromatograms from antemortem blood samples analyzed for ethanol concentration with this technique. The unidentified compound's retention time matches that of methanol on one column but not on the second column. This previously unidentified compound has been identified as isobutylene. The proposed source of the isobutylene contamination historically observed in antemortem blood samples collected in 10-ml gray-top blood collection tubes is the conventional rubber stopper. Isobutylene was detected in deionized water stored in each of the seven lots of 10-ml blood tubes tested; the expiration dates of the tubes tested spanned the years 2002-2022. Misidentification of isobutylene as methanol is possible when using a single-column gas chromatographic system. The presence of isobutylene in blood collected in a gray-top collection tube does not represent laboratory contamination, is not an interferent with blood ethanol quantitation, and does not affect the ethanol concentration in the blood. A 0.150 g/dl aqueous ethanol standard was stored in a gray-top tube to evaluate the potential impact of isobutylene on ethanol quantitation. The solution's average ethanol concentration measured after storage was 0.150 g/dl.

The effect of sample temperature variations during sample preparation on measured blood ethanol concentration.

Since the accuracy of headspace gas chromatographic analysis of blood for ethanol concentration has been so well established over the past several decades, it has become commonplace in court proceedings to attack preanalytical handling of the blood samples including the lack of measuring sample temperature prior to sample preparation. The impact on measured ethanol concentration of allowing refrigerated (~4℃) samples varying amounts of time to equilibrate with room temperature, 24, 4, 3, 2, and 1 h, prior to sample preparation was evaluated. Samples were diluted 1:10 with an internal standard using a diluter/dispenser and analyzed using headspace gas chromatography. The mean ethanol concentration measured for the sixteen samples at each of the five equilibration times was 0.153 g/dl. The F-critical from the one-way ANOVA was 2.4937. The calculated F value was 0.4209. Additionally, the effect on measured ethanol concentration of having calibrators at different temperatures than case samples was investigated. Three groups were analyzed: all calibrators, controls, and samples given 24 h to equilibrate with room temperature, all calibrators, controls, and samples prepared immediately after removal from refrigeration, and calibrators sampled immediately after removal from refrigerator with samples and controls allowed 24 h to equilibrate with room temperature. The mean ethanol concentration measured for the thirty blood samples in each of the three groups was 0.197 g/dl. The F-critical from the one-way ANOVA was 3.1013. The calculated F value was 0.0188. Measured ethanol concentrations were insensitive to the variations in preanalytical conditions evaluated in this study.

The effect of sample hemolysis on blood ethanol analysis using headspace gas chromatography.

Hemolysis, a common occurrence in blood collected for chemical analysis, has been reported to affect analytical test results for some analytes depending upon the material tested and the analytical technique employed. The potential for hemolysis to impact blood ethanol determinations using headspace gas chromatography of samples diluted with an internal standard was investigated. A sample of non-hemolyzed blood and a matched sample of hemolyzed blood were both analyzed thirty times for ethanol concentration using headspace gas chromatography. The mean ethanol concentration measured for the non-hemolyzed samples was 0.0639 g/dl. The mean ethanol concentration measured for the hemolyzed samples was 0.0642 g/dl. The calculated t value, 1.897, was less than the critical t value, 2.002, at a 0.05 level of significance. There was no measured statistical difference detected between the mean blood ethanol concentration determined for a hemolyzed whole blood sample and a non-hemolyzed whole blood sample.

Case Report: Diabetic urinary auto-brewery and review of literature.

Background: Although candiduria is an expected encounter and should not be surprising in uncontrolled diabetes with glucose-enriched urine, urinary auto-brewery is rarely thought of by diabetologists. Moreover, endogenous ethanol production in humans from gut microbiome, urinary tract fungi and bacteria, and intermediary metabolism, has been reported for a long time, particularly in diabetics.  Case description: To alert physicians to the overlooked implication of endogenously produced ethanol both as a biomarker for poor control of diabetes and as a complicating factor, we report this case of an elderly male smoker alcohol-abstinent insulin-dependent Type 2 diabetic patient. Because of circumstantial treatment and incompliance for one week, he developed endogenously produced alcohol intoxication. We proposed candidal urinary auto-brewery evidence sourced from the case history, urinalysis, and culture/identification tests - without excluding other sources. Fortunately, his diet and glycemic control were fairly controlled and, liver and kidney functions were almost normal. Amphotericin B I/V for five days, insulin, and a fluid therapy regimen greatly improved the case and cleared both the candiduria and ethanol from the urine and blood and the patient regained his base-line normal life.   Conclusion: Symptoms of alcohol intoxication should be expected in patients with uncontrolled diabetes that most often correlates with candiduria and/or constipation. These symptoms can be exaggerated in those already suffering a degree of dementia and/or comorbid psychiatric/neurologic affections. Direct wet mount examination of urine under phase contrast microscopy would show the budding yeast cells.  Appropriate antifungal, insulin and fluid therapies regained the base-line norms.

Statistical comparisons of blood alcohol samples from 6-mL and 10-mL grey-top tubes.

Historically, blood alcohol concentration (BAC) studies utilized a 1% concentration of the preservative sodium fluoride (NaF), leaving an information gap supporting usage of lower concentrations of NaF to preserve ethanol. As many forensic laboratories utilize Becton, Dickinson and Company 6-mL gray-top tubes (0.25% NaF), statistical comparisons were conducted to determine whether significant differences exist between BAC values obtained from 6-mL tubes versus 10-mL tubes (1% NaF). Whole blood was spiked at three concentrations, (0.04, 0.08, and 0.15 g/100 mL) and aliquoted into tubes at "low," "medium," and "high" fill volumes. Tubes were split into refrigerated or ambient storage and analyzed after 1, 3, 5, 7, and 30 days, using headspace gas chromatography. Each 6-mL and 10-mL tube pair, prepared, stored, and analyzed under identical conditions, was compared by t-test (95% confidence level). For refrigerated tubes, 32 of 45-tube pairs did not reject the null hypothesis (that 6-mL and 10-mL tubes yield equivalent BACs), and 31 of 45 ambient stored tube pairs did not reject the null hypothesis. Analysis of variance (ANOVA) found no significant differences between 6-mL and 10-mL gray-top tubes for 0.04 and 0.15 g/100 mL concentrations over 30 days; significant differences were observed for 0.08 g/100 mL concentration tubes, which warrants further study. Paired t-tests of grouped samples found no significant differences between 6-mL and 10-mL tubes at any concentration.

Chronic Ethanol Exposure during Adolescence Increases Voluntary Ethanol Consumption in Adulthood in Female Sprague Dawley Rats.

Early alcohol use is a major concern due to the dramatic rise in alcohol use during adolescence. In humans, adolescent males and females consume alcohol at equivalent rates; however, in adulthood males are more likely to consume harmful levels of alcohol. In animal models, the long-term dose-dependent and sex-dependent effects of alcohol exposure during adolescence have not been readily assessed relative to exposure that is initiated in adulthood. The purpose of the present set of experiments was to determine if adolescent exposure to chronic ethanol would predispose male and female rats to greater ethanol intake in adulthood when compared to animals that were not exposed to chronic ethanol exposure until early adulthood. Male and female rats were chronically administered 0.75 g/kg or 1.5 g/kg ethanol or saline for 21 days during adolescence (postnatal day (PND) 30-50) or adulthood (PND 60-80). All rats subsequently underwent 14-days of abstinence (PND 51-64 or PND 81-94, respectively). Finally, all rats were given 30-min daily access to saccharin-sweetened ethanol or saccharin alone from PND 65-80 for adolescent-exposed rats and PND 95-110 for adult-exposed rats. Exposure to 0.75 g/kg ethanol did not alter ethanol or saccharin intake in adolescent-exposed or adult-exposed rats, regardless of sex. In contrast, chronic exposure to the higher 1.5 g/kg dose during adolescence increased ethanol intake in adulthood in female rats. However, there was no change in saccharin intake in animals exposed to 1.5 g/kg ethanol during adolescence or adulthood, regardless of sex. Additionally, there were no clear age- and ethanol-dependent changes in duration of loss of righting reflex and blood ethanol concentrations to a challenge administration of a higher dose of ethanol. The results of the present set of experiments indicate chronic exposure to a high dose of ethanol during adolescence in female rats did indeed predispose rats to consume more ethanol in adulthood. Given that these effects were only observed in adolescent-exposed female rats, these results support a unique vulnerability to the long-term consequences of adolescent ethanol exposure in female rats, an effect that is not merely mediated by the sweetener used in the ethanol solution.

Suppressive Effect of Shiitake Extract on Plasma Ethanol Elevation.

Alcohol is usually consumed with meals, but chronic consumption is a leading cause of alcoholic liver diseases. We investigated if shiitake extracts with a high lentinic acid content (Shiitake-H) and without lentinic acid (Shiitake-N) could suppress the elevation in plasma ethanol concentrations by accelerating ethanol metabolism and preventing ethanol absorption from the gut. Shiitake-H and Shiitake-N suppressed the elevation in concentrations of ethanol and acetaldehyde in plasma, and promoted the activities of alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) in the liver. However, these effects of Shiitake-H were more prominent than those of Shiitake-N. Furthermore, Shitake-H promoted ADH and ALDH activities in the stomach. We also examined the change in plasma ethanol concentration by injecting Shiitake-H or Shiitake-N into the ligated loop of the stomach or jejunum together with an ethanol solution. Shiitake-H suppressed the absorption of ethanol from the stomach and jejunum. In conclusion, Shiitake-H accelerates ethanol metabolism in the stomach and liver and inhibits ethanol absorption in the stomach and jejunum indicating that lentinic acid is a functional component in shiitake.

Testing Antemortem Blood for Ethanol Concentration from a Blood Kit in a Refrigerator Fire.

The stability of ethanol in antemortem blood stored under various conditions has been widely studied. Antemortem blood samples stored at refrigerated temperature, at room temperature, and at elevated temperatures tend to decrease in ethanol concentration with storage. It appears that the stability of ethanol in blood exposed to temperatures greater than 38°C has not been evaluated. The case presented here involves comparison of breath test results with subsequent analysis of blood drawn at the time of breath testing. However, the blood tubes were in a refrigerator fire followed by refrigerated storage for 5 months prior to analysis by headspace gas chromatography. The subject's breath was tested twice using an Intoxilyzer 8000. The subject's blood was tested in duplicate using an Agilent headspace gas chromatograph. The measured breath ethanol concentration was 0.103 g/210 L and 0.092 g/210 L. The measured blood ethanol concentration was 0.0932 g/dL for both samples analyzed. Although the mean blood test result was slightly lower than the mean breath test result, the mean breath test result was within the estimated uncertainty of the mean blood test result. Even under the extreme conditions of the blood kit being in a refrigerator fire, the measured blood ethanol content agreed well with the paired breath ethanol test.

Impact of acute ethanol exposure on body temperatures in aged, adult and adolescent male rats.

The mean population age of the United States continues to increase, and data suggest that by the year 2060 the population of people over the age of 65 will more than double, providing a potentially massive strain on health care systems. Research demonstrates individuals 65 and older continue to consume ethanol, often at high levels. However, preclinical animal models are still being developed to understand how ethanol might interact with the aged population. The current experiments investigated differential body temperature responses in aged rats compared to adult rats and adolescent rats. Aged (19 months of age), adult (70 days of age), or adolescent (30 days of age) male Sprague Dawley rats were administered 1.0 g/kg, 2.0 g/kg, or 3.0 g/kg ethanol, intraperitoneally (i.p.), in a balanced Latin square design. Prior to ethanol administration, a core body temperature via an anal probe was obtained, and then repeatedly determined every 60 min following ethanol exposure for a total of 360 min. In addition, a blood sample was obtained from a tail nick 60, 180, and 300 min following the ethanol injection to investigate the relationship of ethanol levels and body temperature in the same animals. Aged rats had significantly greater reductions in body temperature compared to either adult or adolescent rats following both the 2.0 g/kg and 3.0 g/kg ethanol injection. Additionally, adolescent rats cleared ethanol significantly faster than aged or adult animals. These experiments suggest body temperature regulation in aged rats might be more sensitive to acute ethanol compared to adult rats or adolescent rats. Future studies are needed to identify the neurobiological effects underlying the differential sensitivity in aged rats to ethanol.

Reflections on variability in the blood-breath ratio of ethanol and its importance when evidential breath-alcohol instruments are used in law enforcement.

Variability in the blood-breath ratio (BBR) of alcohol is important, because it relates a measurement of the blood-alcohol concentration (BAC) with the co-existing breath-alcohol concentration (BrAC). The BBR is also used to establish the statutory BrAC limit for driving from the existing statutory BAC limits in different countries. The in-vivo BBR depends on a host of analytical, sampling and physiological factors, including subject demographics, time after end of drinking (rising or falling BAC), the nature of the blood draw (whether venous or arterial) and the subject's breathing pattern prior to exhalation into the breath analyzer. The results from a controlled drinking study involving healthy volunteers (85 men and 15 women) from three ethnic groups (Caucasians, Hispanics and African Americans) were used to evaluate various factors influencing the BBR. Ethanol in breath was determined with a quantitative infrared analyzer (Intoxilyzer 8000) and BAC was determined by headspace gas chromatography (HS-GC). The BAC and BrAC were highly correlated (r = 0.948) and the BBR in the post-absorptive state was 2 382 ± 119 (mean ± SD). The BBR did not depend on gender (female: 2 396 ± 101 and male: 2 380 ± 123, P > 0.05) nor on racial group (Caucasians 2 398 ± 124, African Americans 2 344 ± 119 and Hispanics 2 364 ± 104, P > 0.05). The BBR was lower in subjects with higher breath- and body-temperatures (P < 0.05) and it also decreased with longer exhalation times into the breath-analyzer (P < 0.001). In the post-absorptive state, none of the 100 subjects had a BBR of less than 2 100:1.

Determining the Need for Repeat Testing of Blood Ethanol Concentration: Evaluation of the Synchron Blood Ethyl Alcohol Assay Kit.

BACKGROUND: In clinical laboratories, a common practice used to verify tests prior to reporting is repeat testing. Our objective was to evaluate the differences between the results of blood ethanol concentration (BEC) test repetitions and report on the role of repeat testing to prevent reporting of incorrect results. METHODS: We conducted a retrospective study of data retrieved from the Bursa Yuksek Ihtisas Training and Research Hospital's document management system by calculating the percentage change between repeated BEC test runs. To assess for clinical relevance, the bias between two results from the same sample was compared using the 1988 Clinical Laboratory Improvement Amendments' (CLIA) proficiency testing allowable total error (TEa) limits. RESULTS: From a total of 1,627 BEC tests performed between January 2017 and January 2018, 70% (1,133) were repeat tested. Of these, 830 resulted in BECs between 0-5 mmol/L, of which 237 (28.5%) were above the 25% acceptable TEa. Two hundred seventy-six BEC test results were greater than >14 mmol/L, and there was a good consensus between the initial and repeat test results (99%). In this group, the mean bias was 0.0% (95%, CI = -9.8-9.8%). However, three of the repeat test results were considered significantly different. There were two discordant results in the 5-14 mmol/L ethanol level, and the mean bias was 2.1% (95%, CI = -15.0-19.1%). CONCLUSION: The majority of the repeated BEC test values were the same as the baseline value; therefore, there may be limited benefit in continuing such frequent repeated analyses.