New Zealand's breath and blood alcohol testing programs: further data analysis and forensic implications

Paired blood and breath alcohol concentrations (BAC, in g/dL, and BrAC, in g/210 L), were determined for 11,837 drivers apprehended by the New Zealand Police. For each driver, duplicate BAC measurements were made using headspace gas chromatography and duplicate BrAC measurements were made with either Intoxilyzer 5000, Seres 679T or Seres 679ENZ Ethylometre infrared analysers. The variability of differences between duplicate results is described in detail, as well as the variability of differences between the paired BrAC and BAC results. The mean delay between breath and blood sampling was 0.73 h, ranging from 0.17 to 3.1 8h. BAC values at the time of breath testing were estimated by adjusting BAC results using an assumed blood alcohol clearance rate. The paired BrAC and time-adjusted BAC results were analysed with the aim of estimating the proportion of false-positive BrAC results, using the time-adjusted BAC results as references. When BAC results were not time-adjusted, the false-positive rate (BrAC>BAC) was 31.3% but after time-adjustment using 0.019 g/dL/h as the blood alcohol clearance rate, the false-positive rate was only 2.8%. However, harmful false-positives (defined as cases where BrAC>0.1 g/210L, while BAC< or =0.1g/dL) occurred at a rate of only 0.14%. When the lower of duplicate breath test results were used as the evidential results instead of the means, the harmful false-positive rate dropped to 0.04%.     

Comparison of ethanol concentrations in venous blood and end-expired breath during a controlled drinking study

Concentration-time profiles of ethanol were determined for venous whole blood and end-expired breath during a controlled drinking experiment in which healthy men (n=9) and women (n=9) drank 0.40-0.65 g ethanol per kg body weight in 20-30 min. Specimens of blood and breath were obtained for analysis of ethanol starting at 50-60 min post-dosing and then every 30-60 min for 3-6 h. This protocol furnished 130 blood-breath pairs for statistical evaluation. Blood-ethanol concentration (BAC, mg/g) was determined by headspace gas chromatography and breath-ethanol concentration (BrAC, mg/2l) was determined with a quantitative infrared analyzer (Intoxilyzer 5000S), which is the instrument currently used in Sweden for legal purposes. In 18 instances the Intoxilyzer 5000S gave readings of 0.00 mg/2l whereas the actual BAC was 0.08 mg/g on average (range 0.04-0.15 mg/g). The remaining 112 blood- and breath-alcohol measurements were highly correlated (r=0.97) and the regression relationship was BAC=0.10+0.91BrAC and the residual standard deviation (S.D.) was 0.042 mg/g (8.4%). The slope (0.91+/-0.0217) differed significantly from unity being 9% low and the intercept (0.10+/-0.0101) deviated from zero (t=10.2, P<0.001), indicating the presence of both proportional and constant bias, respectively. The mean bias (BAC - BrAC) was 0.068 mg/g and the 95% limits of agreement were -0.021 and 0.156 mg/g. The average BAC/BrAC ratio was 2448+/-540 (+/-S.D.) with a median of 2351 and 2.5th and 97.5th percentiles of 1836 and 4082. We found no significant gender-related differences in BAC/BrAC ratios, being 2553+/-576 for men and 2417+/-494 for women (t=1.34, P>0.05). The mean rate of ethanol disappearance from blood was 0.157+/-0.021 mg/(g per hour), which was very close to the elimination rate from breath of 0.161+/-0.021 mg/(2l per hour) (P>0.05). Breath-test results obtained with Intoxilyzer 5000S (mg/2l) were generally less than the coexisting concentrations of ethanol in venous blood (mg/g), which gives an advantage to the suspect who provides breath compared with blood in cases close to a threshold alcohol limit.     

Variability in the Blood/Breath Alcohol Ratio and Implications for Evidentiary Purposes

The breath analyzer is an indispensable tool for identifying alcohol levels among drivers. While numerous studies have shown high correlations between blood and breath alcohol concentrations, most are limited by the study design. This study seeks to assess this relationship by minimizing potential measurement bias, document time from alcohol consumption to testing, and adjusting for potential confounders. A blinded study was performed using conditions closely resembling those in the field. The Draeger 7110 MKIII IL breath analyzer was used to assess breath alcohol concentrations (BrAC). Participants were 61 healthy volunteers aged 21–37 years with body mass index ≤30 and no history of alcoholism. A total of 242 valid blood/breath tests were performed in four test sets. The study results showed a high correlation coefficient between BrAC and blood alcohol concentration (BAC) levels (r = 0.983) with high sensitivity (97%) and specificity (93%). This strong association between the breath analyzer and BAC persisted even after adjustment for various stages of alcohol absorption. These results illustrate the high diagnostic sensitivity of the breath analyzer in field‐tested conditions.     

The rate of dissipation of mouth alcohol in alcohol positive subjects

Seven subjects participated in a two-part study to evaluate mouth alcohol dissipation in alcohol positive subjects. In part one, subjects rinsed their mouths with a vodka solution and were breath tested after 1, 2, 3, 4, and 5 min intervals. On average, breath alcohol concentration (BrAC) decreased 20.4% (range 3.2-47.9%) between 1 and 2 min after rinsing. In part two of the study, multiple breath tests were administered after rinsing once with the vodka solution. The BrAC decreased more than 0.020 g/210 L between the first and second tests for all subjects (average 0.095 g/210 L, range 0.021-0.162 g/210 L). The average time for subjects to reach their unbiased BrAC was 9.35 min (range 4-13 min) after rinsing. This study reaffirms the need for duplicate breath testing and confirms that the minimum of a 15-min observation period is sufficient for mouth alcohol to dissipate in alcohol positive subjects.     

The Effects of Gastroesophageal Reflux Disease on Forensic Breath Alcohol Testing

Fifteen test subjects, 10 of whom were diagnosed with gastroesophageal reflux disease (GERD), were dosed with alcohol to BACs above 0.150 g/dL. Blood and breath assays taken at 20-min intervals for 8 h after dosing demonstrated close agreement between postabsorptive BAC and BrAC values. Three subjects exhibited elevated breath alcohol concentrations up to 0.105 g/dL during the absorptive phase that were apparently due to the passage of gastric alcohol through the lower esophageal sphincter not attributable to eruction or regurgitation. The effect of gastric alcohol was not consistently proportional to the amount of unabsorbed gastric alcohol. Absorption of alcohol in the esophagus explains the nonproportionality. Breath samples contaminated by GERD-related alcohol leakage from the stomach into a breath sample were found only when there was a high concentration of alcohol in the stomach. When contaminated breath samples were encountered, they were irreproducible in magnitude.     

Breath alcohol concentration determined with a new analyzer using free exhalation predicts almost precisely the arterial blood alcohol concentration

A new breath alcohol (ethanol) analyzer has been developed, which allows free exhalation, standardizes measured exhaled alcohol concentration to fully saturated water vapor at a body temperature of 37 degrees C (43.95 mg/L) and includes a built-in self-calibration system. We evaluated the performance of this instrument by comparing standardized alcohol concentration in freely expired breath (BrAC) with arterial (ABAC) and venous (VBAC) blood alcohol concentrations in fifteen healthy volunteers who drank 0.6 g of alcohol per kg body weight. The precision (coefficient of variation, CV) of the analyzer based on in vivo duplicate measurements in all phases of the alcohol metabolism was 1.7%. The ABAC/BrAC ratio was 2251+/-46 (mean+/-S.D.) in the post-absorptive phase and the mean bias between ABAC and BrAC x 2251 was 0.0035 g/L with 95% limits of agreement of 0.033 and -0.026. The ABAC and BrAC x 2251 were highly correlated (r=0.998, p<0.001) and the regression relationship was ABAC = 0.00045 + 1.0069 x (BrAC x 2251) indicating excellent agreement and no fixed or proportional bias. In the absorption phase, ABAC exceeded BrAC x 2251 by at most 0.04+/-0.03 g/L when tests were made at 10 min post-dosing (p<0.05). The VBAC/BrAC ratio never stabilized and varied continuously between 1834 and 3259. There was a proportional bias between VBAC and BrAC x 2251 (ABAC) in the post-absorptive phase (p<0.001). The pharmacokinetic analysis of the elimination rates of alcohol and times to zero BAC confirmed that BrAC x 2251 and ABAC agreed very well with each other, but not with VBAC (p<0.001). We conclude that this new breath analyzer using free exhalation has a high precision for in vivo testing. The BrAC reflects very accurately ABAC in the post-absorption phase and substantially well in the absorption phase and thereby reflects the concentration of alcohol reaching the brain. Our findings highlight the magnitude of arterio-venous differences in alcohol concentration and support the use of breath alcohol analyzers as a stand-alone test for medical and legal purposes.     

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.     

Elimination rates of breath alcohol

Legal driving limits are set coequally with 0.5 g/L blood alcohol concentration (BAC) or 0.25 mg/L breath alcohol concentration (BrAC) in Austria as well as in other European countries. As mostly some time elapses between BrAC measurement and driving offence, a back calculation of alcohol concentrations is often required. The calculation of hourly BrAC elimination rates can thereby help to avoid unnecessary variances. A study with 59 participants was performed under social conditions. BrAC was determined with the legally accredited Alcotest 7110 MK III A every 30 min, and concomitantly venous blood samples were drawn. Five hundred and four BrAC/BAC value pairs were evaluated. The overall mean peak BrAC was calculated with 0.456 mg/L (±0.119 mg/L standard deviation). The mean hourly BrAC elimination rate was overall determined with 0.082 mg/L per h (0.050–0.114, 95% range). Mean rate of females (0.087 mg/L h⁻¹) and the according 95% limits were statistically significantly higher than of males (mean rate 0.078 mg/L h⁻¹, p < 0.04). Our results confirm the possibility to implement hourly BrAC elimination rates, provided that adequate statistical ranges and basic forensic scientific rules that have been set up for alcohol back calculations are observed.     

A study concerning the blood/breath alcohol conversion factor Q: concentration dependency and its applicability in daily routine

The conversion factor Q, obtained by division of blood alcohol concentration (BAC) by breath alcohol concentration (BrAC) is a widely discussed topic due to its great variance. By Austrian law, regulations frequently require an estimation of a corresponding BAC by a measured BrAC. It is known that Q depends among other things, on the alcohol kinetic state of the person being tested, which mathematically can be transformed to a dependency on the BrAC. Theoretically calculated Q values per BrAC level form a hyperbola shaped curve, thus decreasing with increasing BrAC values. Applying Austrian forensic standards for BAC and BrAC measurements, these calculations were verified in a study under practical conditions with BAC and BrAC data of 390 individuals. Q decreases from 2629 (+/- 455) for BrAC levels < 0.1 mg/l to 2229 (+/- 160) for a BrAC range of 0.4-0.5 mg/l and increases again to 2428 (+/- 124) for BrAC levels > 0.6 mg/l. Since these results were obtained under realistic practical conditions they can be directly applied in routine forensic expert opinion and can eliminate avoidable variances in the calculation of Q.     

Reliability of breath-alcohol analysis in individuals with gastroesophageal reflux disease.

Gastroesophageal reflux disease (GERD) is widespread in the population among all age groups and in both sexes. The reliability of breath alcohol analysis in subjects suffering from GERD is unknown. We investigated the relationship between breath-alcohol concentration (BrAC) and blood-alcohol concentration (BAC) in 5 male and 5 female subjects all suffering from severe gastroesophageal reflux disease and scheduled for antireflux surgery. Each subject served in two experiments in random order about 1-2 weeks apart. Both times they drank the same dose of ethanol (approximately 0.3 g/kg) as either beer, white wine, or vodka mixed with orange juice before venous blood and end-expired breath samples were obtained at 5-10 min intervals for 4 h. An attempt was made to provoke gastroesophageal reflux in one of the drinking experiments by applying an abdominal compression belt. Blood-ethanol concentration was determined by headspace gas chromatography and breath-ethanol was measured with an electrochemical instrument (Alcolmeter SD-400) or a quantitative infrared analyzer (Data-Master). During the absorption of alcohol, which occurred during the first 90 min after the start of drinking, BrAC (mg/210 L) tended to be the same or higher than venous BAC (mg/dL). In the post-peak phase, the BAC always exceeded BrAC. Four of the 10 subjects definitely experienced gastric reflux during the study although this did not result in widely deviant BrAC readings compared with BAC when sampling occurred at 5-min intervals. We conclude that the risk of alcohol erupting from the stomach into the mouth owing to gastric reflux and falsely increasing the result of an evidential breath-alcohol test is highly improbable.     

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.     

The effect of dentures and denture adhesives on mouth alcohol retention.

A total of 24 alcohol-free, denture-wearing subjects were tested for mouth-alcohol retention times with an Intoxilyzer 5000. The subjects were given 30 mL doses of 80 proof brandy to swish in their mouths without swallowing for 2 min prior to expectorating the dose. Subjects were tested under three conditions: 1) with dentures removed, 2) with dentures held loosely in place without an adhesive, and 3) with dentures plus an adhesive. Beyond 20 min following expectoration, mouth alcohol made no significant contribution to the apparent breath alcohol concentration (BrAC), with trace (less than or equal to 0.01 g/210 L) readings found in only two of the subjects. Denture use, both with and without the concurrent use of adhesives does not significantly affect BrAC as long as a pretest alcohol deprivation period of 20 min is observed.     

Urine/blood ratios of ethanol in deaths attributed to acute alcohol poisoning and chronic alcoholism

The concentrations of ethanol were determined in femoral venous blood (BAC) and urine (UAC) and the UAC/BAC ratios were evaluated for a large case series of forensic autopsies in which the primary cause of death was either acute alcohol poisoning (N=628) or chronic alcoholism (N=647). In alcohol poisoning deaths both UAC and BAC were higher by about 2g/l compared with chronic alcoholism deaths. In acute alcohol poisoning deaths the minimum BAC was 0.74 g/l and the distribution of UAC/BAC ratios agreed well with the shape of a Gaussian curve with mean+/-standard deviation (S.D.) and median (2.5th and 97.5th centiles) of 1.18+/-0.182 and 1.18 (0.87 and 1.53), respectively. In alcoholism deaths, when the BAC was above 0.74 g/l (N=457) the mean+/-S.D. and median (2.5th and 97.5th centiles) UAC/BAC ratios were 1.30+/-0.29 and 1.26 (0.87 and 2.1), respectively. When the BAC was below 0.74 g/l (N=190), the mean and median UAC/BAC ratios were considerably higher, being 2.24 and 1.58, respectively. BAC and UAC were highly correlated in acute alcohol poisoning deaths (r=0.84, residual S.D.=0.47 g/l) and in chronic alcoholism deaths (r=0.95, residual S.D.=0.41 g/l). For both causes of death (N=1275), the correlation between BAC and UAC was r=0.95 and the residual S.D. was 0.46 g/l. The lower UAC/BAC ratio observed in acute alcohol poisoning deaths (mean and median 1.18:1) suggests that these individuals died before absorption and distribution of ethanol in all body fluids were complete. The higher UAC/BAC ratio in chronic alcoholism (median 1.30:1) is closer to the value expected for complete absorption and distribution of ethanol in all body fluids.     

Oral fluid results compared to self reports of recent cocaine and heroin use by methadone maintenance patients

A novel breath-alcohol analyzer based on the standardization of the breath alcohol concentration (BrAC) to the alveolar-air water vapour concentration has been developed and evaluated. The present study compares results with this particular breath analyzer with arterial blood alcohol concentrations (ABAC), the most relevant quantitative measure of brain alcohol exposure. The precision of analysis of alcohol in arterial blood and breath were determined as well as the agreement between ABAC and BrAC over time post-dosing. Twelve healthy volunteers were administered 0.6g alcohol/kg bodyweight via an orogastric tube. Duplicate breath and arterial blood samples were obtained simultaneously during the absorption, distribution and elimination phases of the alcohol metabolism with particular emphasis on the absorption phase. The precision of the breath analyzer was similar to the determination of blood alcohol concentration by headspace gas chromatography (CV 2.40 vs. 2.38%, p=0.43). The ABAC/BrAC ratio stabilized 30min post-dosing (2089±99; mean±SD). Before this the BrAC tended to underestimate the coexisting ABAC. In conclusion, breath alcohol analysis utilizing standardization of alcohol to water vapour was as precise as blood alcohol analysis, the present "gold standard" method. The BrAC reliably predicted the coexisting ABAC from 30min onwards after the intake of alcohol.     

A controlled study of the time-course of breath alcohol concentration after moderate ingestion of ethanol following a social drinking session

This paper evaluates the breath alcohol concentration (BrAC), nausea (feeling of being slightly intoxicated) and subjective driving performance after ingesting a moderate dose of alcohol in the presence of a light meal, which intends to approach a social drinking setting. 119 healthy individuals (69 males and 50 females, aged 21.7+/-3.0) ingested three glasses of wine (95mL each) and their BrAC was determined by an Alcotest 7410 at 15, 30, 45, 60, 90 and 120min post-drinking. 46% of females and no male subjects exceeded a BrAC of 0.25mg/L, the legal limit for driving fixed by some Western countries. 53% of the study population felt nausea during the experimental session and 20% self-reported impairment of their driving skills. In both cases these subjective effects were more pronounced in females. The major determinants of mean BrAC were time post-drinking, gender (male) and body mass index (BMI), all these variables being inversely associated. Females and individuals with a BMI lower than 22.5kg/m(2) were at an increased risk of exceeding the legal limit of BrAC. The feeling of nausea was significantly associated with gender (females), the ingestion of up to 2 drinks on weekdays, and having exceeded a BrAC of 0.25mg/L during the experimental study. The main predictor of self-perception of impaired driving skills was the feeling of nausea, followed by a BrAC in excess of 0.25mg/L. In conclusion, both females and subjects with lower BMI are at an increased risk of exceeding the legal limit of BrAC after moderate alcohol consumption resembling a social drinking setting.     

Evaluation of the Analytical Performance of a Fuel Cell Breath Alcohol Testing Instrument: A Seven‐Year Comprehensive Study

Abstract: Between 2003 and 2009, 54,255 breath test sequences were performed on 129 AlcoSensor IV–XL evidential instruments in Orange County, CA. The overall mean breath alcohol concentration and standard deviation from these tests was 0.141 ± 0.051 g/210 L. Of these test sequences, 38,580 successfully resulted in two valid breath alcohol results, with 97.5% of these results agreeing within ±0.020 g/210 L of each other and 86.3% within ±0.010 g/210 L. The mean absolute difference between duplicate tests was 0.006 g/210 L with a median of 0.004 g/210 L. Of the 2.5% of duplicate test results that did not agree within ±0.020 g/210 L, 95% of these had a breath alcohol concentration of 0.10 g/210 L or greater and 77% had an alcohol concentration of 0.15 g/210 L or greater. The data indicate that the AlcoSensor IV–XL can measure a breath sample for alcohol concentration with adequate precision even amid the effects of biological variations.     

The association of alcohol-induced blackouts and grayouts to blood alcohol concentrations

The primary aim of this study was to investigate the association between measured blood alcohol concentration (BAC) and the presence and degree of amnesia (no amnesia, grayout, or blackout) in actively drinking subjects. A secondary aim was to determine potential factors other than BAC that contribute to the alcohol-induced memory loss. An interview questionnaire was administered to subjects regarding a recent alcohol associated arrest with a documented BAC greater than 0.08 g/dL for either public intoxication, driving under the influence, or under age drinking was administered. Demographic variables collected included drinking history, family history of alcoholism, presence of previous alcohol-related memory loss during a drinking episode, and drinking behavior during the episode. Memory of the drinking episode was evaluated to determine if either an alcohol-induced grayout (partial anterograde amnesia) or blackout (complete anterograde amnesia) occurred. Differences in (1) mean total number of drinks ingested before arrest, (2) gulping of drinks, and (3) BAC at arrest were found for those having blackouts compared with no amnesia; while differences in drinking more than planned were found between the no amnesia and grayout groups. A strong linear relationship between BAC and predicted probability of memory loss, particularly for blackouts was obvious. This finding clinically concludes that subjects with BAC of 310 g/dL or greater have a 0.50 or greater probability of having an alcoholic blackout.     

The response of the Intoxilyzer 4011AS-A to a number of possible interfering substances

Five Intoxilyzer 4011AS-As were tested for their response to eleven chemicals and one mixture of chemicals. The air/water partition ratios were also determined for these eleven chemicals and one mixture. The chemicals tested and their approximate partition ratios were the following: acetaldehyde (190:1), acetone (341:1), acetonitrile (578:1), isoprene (1:1), isopropanol (1671:1), methanol (3229:1), methylene chloride (11:1), methyl ethyl ketone (229:1), toluene (5.5:1), 1,1,1-trichloroethane (14:1), trichloroethylene (20:1), and a 50:50 mixture of 1,1,1-trichloroethane and trichloroethylene (14:1). Of the eleven chemicals and one mixture studied during this experiment, only three, isopropanol, toluene, and methyl ethyl ketone, could reasonably interfere with the test, and then only under unusual circumstances--those circumstances being a slight additive effect to a breath ethanol concentration near the level required for prosecution. Any substantial additive effect from these three substances would illuminate the interference light which invalidates the test. The mean illumination point of the interference light was 0.0286 g/210 L for methyl ethyl ketone, 0.0294 for toluene, and between 0.0116 and 0.0292 for the apparent alcohol concentration for isopropanol, depending on the amount of isopropanol metabolized to acetone. Even with these unusual circumstances considered, the Intoxilyzer 4011AS-A must be viewed as an effective way of determining the ethanol concentration in human breath for evidential purposes.     

血中酒精浓度的回推算研究

目的研究血中酒精浓度值（BAC值）的推算关系。方法对327位自愿受试者饮酒后测定其血中酒精时浓曲线进行分析,计算血中酒精清除率。结果血中酒精消除呈线性,327例血液中酒精消除线性相关系数为0.985±0.019,最小绝对值为0.98,最大绝对值1.000,消除斜率绝对值平均为（0.136±0.037）mg/mL/h,最小绝对值为0.075mg/mL/h,最大绝对值0.266mg/mL/h。结论血液中酒精浓度的推算可根据线性消除关系回推,血液中酒精浓度按照每小时下降0.10mg进行回推算。     

Effects of Homeopathic Mother Tinctures on Breath Alcohol Testing

In some countries, it is illegal to drive with any detectable amount of alcohol in blood; in others, the legal limit is 0.5 g/L or lower. Recently, some defendants charged with driving under the influence of alcohol and have claimed that positive breath alcohol test results were due to the ingestion of homeopathic mother tinctures. These preparations are obtained by maceration, digestion, infusion, or decoction of herbal material in hydroalcoholic solvent. A series of tests were conducted to evaluate the alcoholic content of three homeopathic mother tinctures and their ability to produce inaccurate breath alcohol results. Nine of 30 subjects gave positive results (0.11–0.82 g/L) when tests were taken within 1 min after drinking mother tincture. All tests taken at least 15 min after the mother tincture consumption and resulted in alcohol-free readings. An observation period of 15–20 min prior to breath alcohol testing eliminates the possibility of false-positive results.