Inaccurate Breath Testing Results In Utah Are The Result Of Inaccurate Intoxilyzer Machines And Improper Calibration Techniques Used By Utah Law Enforcement
Do Breath Tests Really Underestimate Blood Alcohol Concentration?13(2) Journal of Analytical Toxicology, 120 (Mar-Apr 1989), Simpson.
Dave’s Plain English Analysis: Depending on whether one’s blood alcohol level is declining or rising, actual blood alcohol measurements may overestimate actual blood alcohol levels in about 25% of individuals who are tested approximately 2 – 4 hours after drinking their last drink.
ARTICLE It has been reported that in the fully postabsorptive state, breath test results underestimate actual blood alcohol concentration (BAC) in 86% of the population. Reanalysis of the data on which this conclusion was based indicates 77% of these subjects were actually underestimated, and 23% were overestimated. Further refinements indicate 68% had their actual BAC underestimated, 16% were acceptably close to the actual BAC, and 16% were overestimated. Perhaps more importantly, comparison of this data with other results indicates fully postabsorptive status may not occur until more than three hours after drinking. Consequently, breath test results may tend to overestimate actual BAC for significant amounts of time after the peak BAC has been reached.
Examining Variables Associated with Sampling for Breath Alcohol Analysis, Victoria Forensic Science Centre, Bell and Flack.
The effects on BAC reading caused by differences in volume of sample delivered, exhaled breath temperature, and alteration of breathing style just prior to delivery, were studied. The variables of BAC, volume, temperature and pressure were measured over the delivery of a breath sample at a rate of 4 times per second in 14 drinking human subjects using 2 specially modified Dräger Alcotest 7110 breath alcohol analyzers. BAC readings at 0.5 and 1.0 L delivery volumes were, on average, 80±4 and 93±2% of the 1.5 L BAC reading respectively. Also, the BAC readings at 0.5, 1.0 and 1.5 L delivery volume were, on average, 76±8, 86±5 and 91±5% of the final BAC reading respectively. A trend of lower percentage of final BAC values with increasing lung vital capacity was observed. Hyperventilation and breath holding for ca. 10 seconds just prior to sample delivery respectively decreased and increased the breath temperature, BAC and percentage of final BAC callused. Standardization of the results of breath analyses to 34.0°C resulted in smoother blood alcohol decay profiles, including the test involving hyperventilation of breath holding. The correlation between simultaneous blood and breath analyses (n+31) was, on the whole, improved by standardization of the breath analysis result to 34.0°C. The differences (breath – blood) between simultaneous blood and breath analyses were, on average, -0.0085 ±0.0070 and -0.0136±0.0074 g/100 mL and the calculated blood/breath partition ratio values were 2509 ±150 and 2336±172 for corrected and uncorrected data respectively. The cooling effect of the mouthpiece on the breath sample was measured as 1.0°C, using both breath from a human subject and simulated breath samples.
Dubowski & Essary, Measurement and Accuracy of Low Breath-Alcohol Concentrations: Laboratory Studies and Field Experience, 23 Journal of Analytical Toxicology 386, 394 (October 1999)
Dave’s Plain English Analysis: Law enforcement may count on the accuracy of breath testing machines at lower than .080 limits (for example .040 for professional truck drivers), as long as two (2) breath tests are performed within twenty (20) minutes of each other and those results are within .020 of each test; please note that Utah law enforcement DOES NOT perform two (2) breath tests as Dubowski mandates but rather only ONE (1) breath test!
ARTICLE Recent federal rules and traffic law changes impose breath-alcohol thresholds of 0.02 and 0.04 g/210 L upon some classes of motor vehicle operators, such as juveniles and commercial vehicle operators. In federally regulated alcohol testing in the workplace, removal of covered workers from safety-sensitive duties, and other adverse actions, also occur at breath-alcohol concentrations (BrACs) of 0.02 and 0.04 g/210 L. We therefore studied performance of vapor-alcohol and breath-alcohol measurement at low alcohol concentrations in the laboratory and in the field, with current-generation evidential analyzers. We report here chiefly our field experience with evidential breath-alcohol testing of drinking drivers on paired breath samples using 62 Intoxilyzer 5000-D analyzers, for BrACs of 0-0.059 g/210 L. The data from 62 law enforcement breath-alcohol testing sites were collected and pooled, with BrACs recorded to three decimal places, and otherwise carried out under the standard Oklahoma evidential breath-alcohol testing protocol. For 2105 pooled simulator control tests at 0.06-0.13 g/210 L the mean +/- SD of the differences between target and result were -0.001 +/- 0.0035 g/210 L and 0.003 +/- 0.0023 g/210 L for signed and absolute differences, respectively (spans -0.016-0.010, 0.000-0.016). For 2078 paired duplicate breath-alcohol measurements with the Intoxilyzer 5000-D, the mean +/- SD difference (BrAC1-BrAC2) were 0.002 +/- 0.0026 (span 0-0.020 g/210 L). Variability of breath-alcohol measurements was related inversely to the alcohol concentration. Ninety-nine percent prediction limits for paired BrAC measurements correspond to a 0.020 g/210 L maximum absolute difference, meeting the NSC/CAOD recommendation that paired breath-alcohol analysis results within 0.02 g/210 L shall be deemed to be in acceptable agreement. We conclude that the field system for breath-alcohol analysis studied by us can and does perform reliably and accurately at low BrACs. __________________________________________________________
Dubowski, Quality Assurance In Breath – Alcohol Analysis, 18 Journal Of Analytical Toxicology 306 (Oct. 1994).
Dave’s Plain English Analysis: There are three measurements associated with breath testing for alcohol content; VOLUME (fixed at 80 cc’s by the aluminum breath chamber); BREATH TEMPERATURE (fixed at 34 degrees Centigrade on the CMI Intox 5000 and 8000, BUT individually variable from 32.7 to 37.8 degrees centigrade); and PARTITION RATIO (fixed at 2100:1, BUT individually variable from 1500:1 – 3400:1). These individual variables greatly influence the end result; for example, a person with 34 degree Centigrade (93.2 degrees Fahrenheit), the same as that programmed into the Intoxilyzer machine, BUT having a 1500:1 partition ratio rather than the 2100:1 preprogrammed into the machine, will register a whopping .160 BrAC when they have a blood alcohol level (BAC) of .080! That is double what they actually have as a blood level. Likewise, a person having the preprogrammed 2100:1 partition ratio, but having a breath temperature of 37 degrees Centigrade (98.6 degrees Fahrenheit – or normal body temperature, will result in a recorded breath alcohol result of nearly 20% (18.2%) higher than their actual blood alcohol level – for example, a real world legal Blood Alcohol Concentration of .079 will result in a breath result of .096). Breath testing analysis can be accepted as accurate in a law enforcement setting as long as very strict guidelines are followed, such as a pre-test deprivation period of at least fifteen (15) minutes; a comprehensive machine calibration testing program where records are kept forever; and DUPLICATE TESTING OF EACH SUBJECT ARE PERFORMED TWENTY (20) MINUTES APART, WITH TEST RESULTS WITHIN .020 OF EACH TEST. Please note that Utah Law Enforcement is the only state agency that permits single rather than duplicate testing required by Dubowski!
ARTICLE Evidential breath-alcohol testing requires an adequate quality assurance (QA) program to safeguard the testing process and validate its results. A comprehensive QA program covers (a) test subject preparation and participation; (b) the analysis process; (c) test result reporting and records; (d) proficiency testing, inspections, and evaluations; and (e) facilities and personnel aspects. Particularly important are the following necessary scientific safeguards as components of quality control: (a) a pretest deprivation-observation period of at least 15 minutes; (b) blank tests immediately preceding each breath-collection step; (c) analysis of at least duplicate breath specimens; and (d) a control test accompanying every subject test. These safeguards have withstood adversarial challenges in the judicial system for more than 30 years. Abstract courtesy of www.pubmed.org – A service of the National Library of Medicine and the National Institutes of Health ____________________________________________________
Breathalyzer Accuracy In Actual Law Enforcement Practice: A Comparison of Blood vs. Breath Results In Wisconsin Drivers, 32 Journal Of Forensic Sciences, Harding and Field.
Gulberg, Distribution of the Third Digit in Breath Alcohol Analysis, 36 Journal of Forensic Science 976 (1991)
Dave’s Plain English Analysis: Only 33% of breathtests correlated to associated blood tests, however, breath is more often lower than blood by as much as 15% when all other variables are accounted for and implemented.
ARTICLE Breathalyzer and blood-alcohol results from drivers arrested for operating a motor vehicle while intoxicated and for related offenses were compared during a two-year period. Four hundred and four pairs of breath- and blood-alcohol results from specimens collected within 1 h of each other were studied. Blood-alcohol concentrations ranged from zero to 0.421% weight per volume (w/v). Breath-alcohol concentrations ranged from zero to 0.44 g/210 L. The mean Breathalyzer result was 0.16 g/210 L. The mean blood-alcohol result was 0.176% w/v. Compared to the blood-alcohol result, Breathalyzer results were lower by more than 0.01 g/210 L 61% of the time, within 0.01 g/210 L 33% of the time, and higher by more than 0.01 g/210 L 6% of the time. __________________________________________________________
Hlastala, Breathing-Related Limitations to the Alcohol Breath Test. DWI Journal: Science and Law 17: 1-4, (December, 2002) Hlastala, Physiological Errors Associated with Alcohol Breath Testing, 9 The Champion 16 (1985)
Dave’s Plain English Summary / Analysis: The design of current Intoxilyzers made by CMI, including the CMI 5000 and 8000, do not allow for actual breath temperature measurement, or partition ratio, such that mouth alcohol may be expected to affect the measured result, resulting in a falsely increased result by as much as 100%, especially when duplicate (within .020) breat testing is not administered. The design of current breath alcohol testers lead to several potential errors owing to normal physiological factors. Breath testing for blood alcohol concentration originated over thirty years ago. At that time Understanding of the physiology of the lung was quite primitive. As a result testing procedures contain implicit errors. There are four major sources of error: (1) variability in the normal measured blood-breath alcohol partition ratio which may lead to a potential error of ±30% but individual cases can have even greater error: (2) variability in breathing patter, because of the interaction of alcohol with the airway surface, can cause an error of as much as ± 50%; (3) variation in normal body temperature can cause an error of ±6% for each degree centigrade and: (4) variation in normal blood hemotocrit can cause and error of ±14%. There errors alone add up to a very high random variability, sometimes as great as 100%. Since the errors are caused by the normal physiology of the body and are external to the breath testing instrument, every breath tester currently used is subject to large potential error when used to estimate blood alcohol concentration.____________________________________________________Hlastala, The Alcohol Breath Test – A Review, 84 (2) Journal of Applied Physiology 401, 402-03 (1998) The alcohol breath test (ABT) is evaluated for variability in response to changes in physiological parameters. The ABT was originally developed in the 1950s, at a time when understanding of pulmonary physiology was quite limited. Over the past decade, physiological studies have shown that alcohol is exchanged entirely within the conducting airways via diffusion from the bronchial circulation. This is in sharp contrast to the old idea that alcohol exchanges in the alveoli in a manner similar to the lower solubility respiratory gases (O2 and CO2). The airway alcohol exchange process is diffusion (airway tissue) and perfusion (bronchial circulation) limited. The dynamics of airway alcohol exchange results in a positively sloped exhaled alveolar plateau that contributes to considerable breathing pattern-dependent variation in measured breath alcohol concentration measurements. _____________________________________________________Johnson, Horowitz, Maddox, Wishart, Shearman, Cigarette Smoking and Rate of Gastric Emptying and the Effect on Alcohol Absorption, 302 British Medical Journal 20 (1991) OBJECTIVE–To examine the effects of cigarette smoking on alcohol absorption and gastric emptying. DESIGN–Randomised crossover study. SETTING–Research project in departments of medicine and nuclear medicine. SUBJECTS–Eight healthy volunteers aged 19-43 who regularly smoked 20-35 cigarettes a day and drank small amounts of alcohol on social occasions. INTERVENTIONS–Subjects drank 400 ml of a radiolabelled nutrient test meal containing alcohol (0.5 g/kg), then had their rates of gastric emptying measured. Test were carried out (a) with the subjects smoking four cigarettes an hour and (b) with the subjects not smoking, having abstained for seven days or more. The order of the tests was randomised and the tests were conducted two weeks apart. MAIN OUTCOME MEASURES–Peak blood alcohol concentrations, absorption of alcohol at 30 minutes, amount of test meal emptied from the stomach at 30 minutes, and times taken for 50% of the meal to leave the proximal stomach and total stomach. RESULTS–Smoking was associated with reductions in (a) peak blood alcohol concentrations (median values in non-smoking versus smoking periods 13.5 (range 8.7-22.6) mmol/l v 11.1 (4.3-13.5) mmol/l), (b) area under the blood alcohol concentration-time curve at 30 minutes (264 x 10(3) (0-509 x 10(3)) mmol/l/min v 140 x 10(3)) (0-217 x 10(3) mmol/l/min), and (c) amount of test meal emptied from the stomach at 30 minutes (39% (5-86%) v 23% (0-35%)). In addition, smoking slowed both the 50% gastric emptying time (37 (9-83) minutes v 56 (40-280) minutes) and the intragastric distribution of the meal. There was a close correlation between the amount of test meal emptied from the stomach at 30 minutes and the area under the blood alcohol concentration-time curve at 30 minutes (r = 0.91; p less than 0.0001). CONCLUSION–Cigarette smoking slows gastric emptying and as a consequence delays alcohol absorption.Dave’s Plain English Analysis:: Smoking slows gastric emptying which lowers peak BAC. __________________________________________________________
Jones, Evaluation of Breath-Alcohol Instruments, 28 Forensic Science International 147 (1985) This paper reports results from a field trial with a breath-alcohol screening device–Alcolmeter pocket model. Breath tests were made with drivers apprehended during routine controls (road-blocks), for traffic violations and those involved in traffic accidents. Of 908 roadside breath tests made with chemical reagent tubes, 343 showed zero alcohol (no colour change) and these results were confirmed by Alcolmeter. Alcohol was detected in 191 tests but the level was judged as being below the legal limit of 0.50 mg/ml. The Alcolmeter results, however, ranged from 0 to 1.22 mg/ml (mean 0.21 mg/ml) and 15 individuals (7.8%) were above the legal limit. There were 373 positive chemical tube breath screening tests whereas in 5 cases (1.3%) Alcolmeter indicated a blood-alcohol level below 0.50 mg/ml. Duplicate determinations with the Alcolmeter device were highly correlated r = 0.93 +/- 0.02 (+/- S.E.), P less than 0.001. The standard deviation of a single breath-alcohol analysis under field conditions was +/- 0.10 mg/ml which corresponds to a coefficient of variation of 10%. The time interval between positive roadside breath test and blood-sampling ranged from 5 to 220 min (median 62 min). The results were therefore adjusted by 0.15 mg/ml per hour to compensate for ethanol metabolised between the time of sampling blood and breath. The corrected blood and breath values were well correlated r = 0.84 +/- 0.03, P less than 0.001 but the predictive power of the regression relationship was poor. The regression equation was y = 0.27 +/- 0.65x and the standard error estimate was +/- 0.21 mg/ml at the mean concentration of ethanol of 1.0 mg/ml. __________________________________________________________ Jones, How Breathing Technique Can Influence the Results of Breath-Alcohol Analysis, 22 (4) Medicine, Science, and the Law 275, 275 (1982) This paper reports experiments to test how a person’s breathing technique can influence the concentration of ethanol and the temperature of end-expired breath samples. The experiments were performed with healthy men after they drank a moderate dose of ethanol and the concentration of ethanol in breath was determined by gas chromatography. The results were compared with control breaths, which were deep inspirations and forced expirations of room air, analyses within 2-3 minutes of the test-breath sample. With breath-holding (30 seconds) before expiration, the concentration of ethanol increased by 15-7±2-24 percent (mean = SE) and the temperature of breath rose by 0-6 ±0-09°C.Hyperventilating for 20 seconds, immediately before the analysis of breath, decreased the concentrations of ethanol by 10-6 ±1-37 per cent and the breath temperature dropped by 1-0 ±0-22°C. Keeping the mouth closed for 5 minutes (shallow breathing) increased expired ethanol concentration by 7-3 ±1-2 per cent and the breath temperature rose by 0-7 ± 0-4°C. After a slow (20 second) exhalation expired ethanol increased by 2-0± 0-71 per cent but breath temperatures remained unchanged from control tests. My results suggest that the changed in expired ethanol concentrations are partly caused by the rise or fall in the temperature of breath. But an equally important factor is the amount of time the breath spends in contact with the mucous membranes of the upper respiratory tract. A long contact time increases the concentration of ethanol and rapid ventilation lowers it. Regardless of the breathing technique tested the results recovered to control values immediately the subjects began breathing normally again. Dave’s Plain English Analysis: Holding breath for 30 seconds = 15.7% increase. Hyperventilating for 20 seconds; decreased by 10.6% Mouth closed and shallow – nasal breathing for 5 minutes = increase by 7.3%. Slow 20 second exhale = 2% increase. Factors = increased temperature of breath Increased contact with mucous membranes (also see Ohlson (1990)) __________________________________________________________ Jones, Physiological Aspects of Breath-Alcohol Measurement, 6 Alcohol, Drugs and Driving, 2 This paper gives review and opinion about several aspects of quantitative evidential breath alcohol analysis used in traffic law enforcement. In particular, physiological aspects of breath testing are covered, with emphasis on factors influencing the precision and accuracy of results. The increasing use of punishable limits of blood and/or breath-alcohol concentration makes chemical test evidence a popular target for defense attack and litigation in trials concerned with driving under the influence (DUI). Historical developments in theory and application of breath testing as evidence of intoxication are briefly outlined. The absorption, distribution and elimination of alcohol in the human body are covered as background for understanding the passage of alcohol from blood to breath. Research on the blood/breath alcohol ratio and the factors that influence this relationship including mouth-alcohol, regurgitation, breathing technique, arteriole-venous differences, blood hematocrit value, pulmonary disease, body temperature, expired air temperature and temperature and humidity of ambient air are critically evaluated and discussed. Both blood-alcohol and breath-alcohol measurements are suitable to provide objective evidence of alcohol load in the organism and the associated impairment of driving skills. With per se statutes, the magnitude of sampling and analytical errors inherent in methods of analyzing alcohol for legal purposes must be carefully documented. The final prosecution result can be adjusted to allow for uncertainties in the analytical procedures used.__________________________________________________________Simpson, Accuracy and Precision of Breath Alcohol Measurements for Subjects in the Absorptive State, 33(6) Clin. Chem. 753 (June 1987) Published data are analyzed in order to estimate the accuracy of breath-alcohol measurements for subjects during absorption of orally ingested ethanol. Simultaneous measurements of breath alcohol concentration (BrAC) and venous blood alcohol concentration (VBAC) show that actual VBAC can be overestimated by more than 100% for a significant amount of time after drinking stops. The maximum error found for four individual subjects is +230%, +190%, +60%, and +30%. The magnitude of these errors indicates that results from quantitative evidential breath alcohol analyzers are far less accurate for the absorptive state than they are during the postabsorptive state, but the specifications for accuracy and precision given by manufacturers of these instruments do not reflect this. The results also indicate that there is a significant likelihood that subjects will be in the absorptive state when tested under field conditions. I conclude that estimates of BAC based on BrAC measurements are not reliable in the absorptive state and that the uncertainty associated with such estimates should be accounted for, particularly when the results are used in connection with law enforcement.__________________________________________________________ Accuracy and Precision of Breath-Alcohol Measurements for Random Subjects in Postabsorptive State, 33 Clinical Chemistry 261(1987) Simpson. The accuracy of estimates of blood-alcohol concentration based on measurements of breath-alcohol concentration in a randomly selected subject by a random quantitative evidential breath-alcohol analyzer is evaluated with respect to the breath analyzer itself, its calibration, and the biological variables of the subject being tested. There are no suitable experimental data for rigorous determination of the overall accuracy, so I estimate it from the CV of the available data. I find that the uncertainty in these breath-analyzer readings for a random subject in the postabsorptive state is at least +/- 15%, +/- 19%, or +/- 27%, depending on whether +/- 2 CV, the experimental range, or +/- 3 CV, respectively, is used to express the overall uncertainty. Over 90% of this uncertainty is due to biological variables of the subject, and at least 23% of subjects will have their actual blood-alcohol concentration overestimated. Manufacturers’ specifications for the accuracy and precision of these instruments are inconsistent with the experimental values reported in the literature and I recommend that an appropriate amount of uncertainty be reflected in the results from these breath analyzers, especially when they are used for law-enforcement purposes.