The Effect of GERD on a Breath Test
Part 2 - Does GERD affect the results of a breath alcohol test?
Counterpoint Volume 5: Issue 2 - Article 2 (March 2021)
An article for participants in the myCAMprogram
Jan Semenoff, BA, EMA
Forensic Criminalist
Article information:
3500 words (approximately 20-25 minutes); Video - 43:07 minutes.
Important Note:
This information is intended for participants in Family Monitoring Programs where a small, legally allowable alcohol concentration is permitted. If you are under a zero-tolerance program, any alcohol use is a violation — regardless of your medical condition. ALWAYS follow your specific program rules.
This information is intended for participants in Family Monitoring Programs where a small, legally allowable alcohol concentration is permitted. If you are under a zero-tolerance program, any alcohol use is a violation — regardless of your medical condition. ALWAYS follow your specific program rules.
The question now comes: Does GERD affect the results of a breath alcohol test?
If you look at the forensic literature presented in the past in the refereed scientific journals, the answer is an unambiguous NO. But is this assumption correct? Is further research necessary? I think GERD presents a more uncertain causal relationship with breath alcohol testing than perhaps first thought. Let’s examine, critically, the data sets obtained, and consider the findings and conclusions.
If you look at the forensic literature presented in the past in the refereed scientific journals, the answer is an unambiguous NO. But is this assumption correct? Is further research necessary? I think GERD presents a more uncertain causal relationship with breath alcohol testing than perhaps first thought. Let’s examine, critically, the data sets obtained, and consider the findings and conclusions.
BrAC versus BAC
Before we begin, please pay close attention to the acronyms used throughout this article: BAC refers to BLOOD alcohol concentration, while BrAC refers to BREATH alcohol concentration. You should be comfortable in differentiating the two terms.
Before we begin, please pay close attention to the acronyms used throughout this article: BAC refers to BLOOD alcohol concentration, while BrAC refers to BREATH alcohol concentration. You should be comfortable in differentiating the two terms.
Video presentation on GERD & breath alcohol testing
Video duration 43:07. Click on the video to play.
Gastroparesis
Gastric emptying is the process where the stomach contents are moved through to the small intestine. Liquids normally empty faster than solids; smaller objects faster than larger ones. Under normal circumstances, about 40% of the stomach contents should have passed through to the small intestine within an hour or two, depending on the contents (liquid, solid, etc.)
It is far better to express this in terms of normal ranges of stomach emptying in healthy subjects:
It is far better to express this in terms of normal ranges of stomach emptying in healthy subjects:
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Source: McCallum R, Sabu J.G: Gastroparesis. Clinical Perspectives in Gastroenterology May/June 2001 pg. 147-154
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Gastroparesis is a condition where food remains in your stomach for longer than it should.
A minority of patients with GERD, about 20%, have been found to have stomachs that empty abnormally slowly after a meal. Dr. A.W. Jones (2005) identified the presence of unabsorbed alcohol in the stomach among GERD patients “several hours” after drinking.
A minority of patients with GERD, about 20%, have been found to have stomachs that empty abnormally slowly after a meal. Dr. A.W. Jones (2005) identified the presence of unabsorbed alcohol in the stomach among GERD patients “several hours” after drinking.
In fact, this delayed gastric emptying is one of the factors that a gastroenterologist considers in making a GERD diagnosis. This delayed stomach emptying creates a few issues:
- Food and stomach contents (including alcohol) will remain within the stomach for a longer period of time before the contents are released to the small intestine. This may be 3-4 hours after ingestion.
- Any unabsorbed alcohol will also remain within the stomach walls. Keep in mind that most forensic toxicologists will testify that all stomach alcohol is fully absorbed within 30-60 minutes from the end of consumption.
- The mixture in the stomach is acidic, and causes the patient to have heartburn and discomfort, leading to reflux, or regurgitation, of the stomach contents back into the esophagus.
- The leakage of the LEV (Lower Esophageal Valve) creates the situation where the unabsorbed alcohol in the stomach may be released, potentially contaminating the results of a sample of deep lung air. Erupted stomach gases may mix with the exhaled lung air to artificially inflate the reported BrAC readings.
With a diagnosed medical condition such as GERD, it is possible that the leakage in the LEV would introduce a trace amount of alcohol remaining in the stomach back into the esophagus. This would have the net effect of elevating the reading obtained. Remember that modern breath alcohol instruments are extremely sensitive, measuring anywhere from 4-10 millionths of a gram of alcohol in a roadside screening device to 4- 10 thousands of a gram of alcohol in an evidentiary breath tester (all for a reading of 0.08grams/210L of breath). A little bit of contamination makes a big impact…
There needs to be unabsorbed alcohol in the stomach that makes its way back into the esophagus for any of this to matter. The issue of gastroparesis is vitally important in understanding the interplay, if any, of GERD on reported breath alcohol test results.
Let's critically examine the reported GERD studies:
Reliability of Breath-Alcohol Analysis in Individuals with Gastroesophageal Reflux Disease
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Kechagias, S., Jonsson, K-A, Franzen, T., Andersson, L and Jones, A.W., Reliability of Breath-Alcohol Analysis in Individuals with Gastroesophageal Reflux Disease, Journal of Forensic Sciences, 1999; 44(4): 814-818.
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Kechagias et al (1999) investigated the relationship between breath and blood alcohol concentrations in ten people (5 males, 5 females) who were all severe GERD sufferers, so much so that they were all scheduled for corrective LEV anti-reflux surgery. Each provided a breath sample on two occasions: First, under normal circumstances; Second, under circumstances where the researchers placed the subject in an abdominal compression belt and attempted to provoke some sort of gastric reflux by tightening the belt - basically squeezing a belch out of them. During each session, concurrent breath and blood samples were obtained.
Four of ten of the subjects “definitely experienced gastric reflux” during the study. The authors reported no apparent correlation between GERD and increased BrAC readings while in the elimination phase of alcohol metabolism. However, some of their test subjects showed elevated BrAC readings compared to their BAC’s during the absorptive phase.
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Figure 1 - Data shows that a percentage of people tested showed apparent false-positive BrAC-BAC readings during the absorptive phase of alcohol metabolism, with some readings as much as 0.030 grams/210L higher. Click on each graph to enlarge.
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The BrAC readings were as much as 0.030 grams/210 L higher. The elevated readings were reported in 4 of 10 test subjects [1]. I would respectfully suggest that their assertion that GERD does not elevate the reported BrAC readings may not be supported by the data they obtained.
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[1] … and maybe even five of ten, by looking at the graphs they supply, although the inflated reading may be within the limits of detection of the device used. If not, it was an extremely minor inflation, and would most likely be negated by truncation of the reported reading.
Note that truncation, as a practice, is being abandoned by more and more jurisdictions as they change their respective per se laws to include “at or exceeding 80 milligrams” or, “equal to or more than 0.080 grams”. Additionally, the trend in reporting the BrAC reading to the third decimal (i.e. – 0.081 grams) is increasing. |
The authors write:
"These graphs show that the BrAC in some subjects tends to overstate venous BAC during the absorption phase of the curves, for the first 90 minutes after the end of drinking; the maximum deviation BrAC-BAC was 30mg/210L (0.03 grams/210L)." |
It should be noted that the reported BrAC elevated readings occurred ONLY during the absorptive phase, when unabsorbed alcohol is found in high concentrations in the stomach. It has been long known that a breath reading obtained during the absorption phase is higher than the true blood alcohol concentration. Conversely, in the elimination phase, the breath reading has a tendency to be lower than the true blood alcohol concentration.
The increased BrAC readings only occurred during the absorptive phase. In the elimination phase, the measured blood (BAC) was always more than the measured breath (BrAC). Therefore, the researchers concluded 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-test is highly improbable.”
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AUTHOR'S NOTE: This paper, more than any other, is cited by prosecutors as a means of refuting any assertion that GERD elevated the breath test due to this last sentence. You, and your expert, need to know what this paper really means, what the data actually indicates, and the veracity of the author's conclusions. |
The researchers conclude:
"We conclude that the risk of a person experiencing gastric reflux during the time he or she participates in a breath-alcohol procedure is very low. Even if reflux does occur, our study shows that it is not very likely that an abnormally high BrAC reading will be obtained. However, the mandatory 15-minute observation period still remains an important element of the evidential breath-alcohol test protocol because this can help to rebut allegations that gastric reflux occurred. Likewise, the routine practice of analyzing duplicate breath samples is an additional safeguard in this respect." |
One of the researchers, Dr. A. W. Jones, has since written letters or articles calling for further research and investigation on GERD and its impact on breath alcohol testing, noting the lack of research on the subject:
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The Effects of Gastroesophageal Reflux Disease on Forensic Breath Alcohol Testing
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Booker, J. L., and Renfroe, K., The Effects of Gastroesophageal Reflux Disease on Forensic Breath Alcohol Testing, The Journal of Forensic Sciences, 2015.
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In a 2015 paper, American researchers Booker and Renfroe dosed 15 test subjects (5 as a control group; 10 of whom were diagnosed with GERD and gastroparesis). Previously having fasted for 10 hours, the subjects were given a light meal consisting of enchiladas, rice, beans, and moderately spicy salsa with corn chips. (If you're wondering about the choice of food, the researchers and participants were located in Texas)
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They were then dosed with beverage alcohol to a fairly significant BAC level of about 0.150 g/dL or higher - in other words, about twice the legal limit. Twenty minutes following alcohol dosing was concluded, concurrent breath and venous blood samples were collected in 20-minute intervals for the next 8 hours. To ensure repeatability of the results, each subject was tested twice, following the same consumption pattern, tested three weeks apart.
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Of the three GERD patients with elevated BrAC readings, their BAC graphs were remarkably similar from one drinking episode to the next conducted three weeks apart. It was the irreproducible difference in their BrAC pattern that suggested to the researchers that GERD was a viable explanation for the BrAC-BAC difference. However, they felt that the limited data they obtained precluded identifying GERD as the sole causal factor.
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Figure 2 - Data shows that 3 of 10 GERD patients tested showed apparent false-positive BrAC-BAC readings during the absorptive phase of alcohol metabolism, with some readings as much as 0.030 g/dL higher. Click on each graph above to enlarge. One point that is interesting is the time to peak BAC among the GERD patients - the average was 3 hours and 20 minutes - remember the issue of gastroparesis...
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Look closely at Subject G7 (Above, on the right, and shown below in greater detail):
- Notice the first reading on the very far left, indicated as Line #1. The BAC seems to be about 0.04 grams/210L, while the corresponding BrAC is about 0.15 grams/210L - an over-reporting by 0.11 grams.
- The next sample pair (Line #2) shows a BAC at 0.08 Grams/210L with the simultaneous breath sample at 0.15 grams/210L - an over-reporting of 0.07 grams.
- The third sample pair, shown in the graph at the right (Line #3) shown a blood concentration of 0.05 grams/210 L with corresponding breath sample at .012 grams/210L - an over-reporting of the breath reading by 0.07 grams.
- Finally, at line #4 the BAC is about 0.09 grams/210 L with the simultaneous breath sample reporting at about 0.13 grams/210L - an error of an additional 0.04 grams.
Figure 3 - The sampling pairs of Booker's Test Subject G7 showing an apparent BrAC over-reporting (at line #1) of about .105 grams (reported in the Abstract as 0.105 g/dL).
The data in the BrAC-BAC graphs indicates an over-reporting by Test Subject G7 by 0.11 grams, 0.07 grams, 0.07 grams and 0.04 grams for four separate breath and blood concentration pairings, and indeed they identify in the Abstract that "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." Inexplicably, they conclude, as we shall see, that "GERD-related alcohol leakage from the stomach into a breath sample is therefore an essentially irrelevant source of potential error in forensic breath testing".
I would point out to you that the breath curves (the BrAC profiles) do NOT show a random reading indicative of a burp, belch or other fresh mouth alcohol contaminate. The first reading that is about 0.11 g/dL higher is NOT an outlier in the data set. Indeed, the breath data points follow along without apparent anomalies. What is worse is that if breath samples #1 & #2 are compared, they are both around 0.15 grams. They would be within 0.02 grams of one another, and considered reliable. Similarly, breath samples #3 & #4 are at 0.12 and 0.13 grams/210L and would likewise be considered a reliable set of breath samples with an apparent 0.02 grams agreement.
Booker and Renfroe also suggest that any stomach gas contamination or regurgitation would be picked up by the slope detector in the breath test device, depending upon the type of instrument used. They also felt that a second replicate test conducted within a short time would identify any apparent falsely inflated BrAC reading. However, even though they experienced instances of inflated readings, they do not indicate if the slope detector actually picked up any mouth alcohol contaminated readings on the breath test device they used in their study (an Intoxilyzer 5000EN). given the breath readings produced by the test subjects, and apparent 0.02 agreement between the reading, I would suggest that the device, an Intoxilyzer 5000EN, probably did NOT indicate any INVALID TEST results.
As with the Kechagias & Jones study, elevated BrAC-BAC differences were only observed during the absorptive phase of alcohol metabolism.
They concluded:
- GERD related BrAC-BAC elevation occurs infrequently
- GERD is episodic in nature
- Only 3 of 10 GERD patients produced incompatible BrAC-BAC results
- GERD is not a factor in the elimination phase
- GERD BrAC-BAC variability only occurs when a high concentration of alcohol is present in the stomach
- Only one instance of high GERD related leakage occurred at more than 0.030grams/210L. This value is not supported in their reported data.
Their final conclusion:
“GERD-related alcohol leakage from the stomach into the breath sample is therefore an essentially irrelevant source of potential error in forensic breath testing.” |
I remain concerned that a demonstrated GERD BrAC-BAC variability in 30% of the tested GERD test subjects, with the potential for an elevation as high as 0.105 grams/210L cannot be so easily dismissed as “an essentially irrelevant source of potential error”.
Breath Alcohol Analysis in One Subject with Gastroesophageal Reflux Disease
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Gullberg, R., Breath Alcohol Analysis in One Subject with Gastroesophageal Reflux Disease, Case Report, Journal of Forensic Sciences, Vol. 46 No. 6, pages 1498-1503, 2001.
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In 2001, Rod Gullberg additionally reported on a case study where the measured BrAC reading exceeded the known BAC reading by a little more than 0.010 grams/210L. The patient, a 23-year old male with a diagnosis of GERD provided breath samples with two blood draws. The difference in BrAC-BAC readings (0.010 grams/210L) was considered insignificant.
Figure 4 - The absorption and elimination profile of the test subject, showing a single BrAC reading that exceeded the BAC reading while the subject was at his peak of absorption.
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However, Gullberg thought that GERD patients should be tested following "sound forensic practices", including a 15-minute observation period, duplicate breath testing, the use of a breath instrument that employs a slope detector, and appropriate operator training.
Figure 5 - An excerpt from Gullberg's case study, calling for sound forensic practice when testing known GERD patients.
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Issues with GERD and breath alcohol testing
Remember the notion of delayed stomach absorption as a sign of GERD, often approaching 2-4 hours or more, when the forensically accepted value to reach full absorption is 30-60 minutes. The studies cited identify the necessity of unabsorbed alcohol being present in the stomach during the absorptive phase of alcohol metabolism before GERD was even remotely to be considered a causal factor in BrAC-BAC elevations. The Booker and Renfroe GERD patients averaged 3.3 hours to peak BAC, as measured by both breath and blood readings obtained for those with elevated BrAC readings
What is of concern is that in all three papers cited, researchers demonstrated that known GERD patients were providing elevated BrAC readings in comparison to known BAC blood draw values, about 30% of the time, with readings as much as 0.105 grams/210L higher yet dismissed, out of hand, the possibility that GERD was playing a contributive factor.
It seems that the researchers are unable or unwilling to assert that GERD is a causal factor in apparent BrAC-BAC elevations due to the fact that they occurred only during the absorptive phase, when these elevations are known to exist among normal, healthy people. They simply do not have sufficient data to support, statistically, that GERD is a causal factor.
So again, we remain where Dr. A. W. Jones left us more than a decade ago – calling for further research on the subject. More data obtained, collected under controlled circumstances, could conceivably provide more insight into the interplay between GERD and breath alcohol testing.
The residual alcohol detection algorithm revisited
As noted previously, Booker and Renfroe suggest that the Residual Alcohol Detection System (RADS) algorithms in modern evidentiary breath test devices would identify any stomach eruption as fresh-mouth alcohol and report an invalid test result. Can this be relied upon?
Due to the pattern of emanation of alcohol from both the upper digestive tract along with the normal pathway from the lungs in a GERD patient, the RADS of modern breath alcohol analyzers are incapable of distinctly separating readings of the two. In short, alcohol emanates from BOTH the lungs AND the upper GI Tract, at roughly the same rate.
The residual alcohol detectors are designed to identify a sudden rise in measured BAC was a subsequent sharp drop in BAC from second to second during the breath test. False positives associated with GERD do not follow this “rise and drop” pattern and are not easily detected by the programmed algorithms. Under these conditions, it is known that the so-called “slope detectors” can falsely interpret this mouth alcohol bias and over-report the true BAC reading (Hlastala, 2006 and Gullberg, 2000).
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Figure 6 - GERD will have a tendency towards a breath exhalation profile on the left, above, where there will be consistent leakage from the LEV. The profile on the right shows the "rise and drop" pattern that the Residual Alcohol Detection System (slope detector) is programmed to look for.
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It has been my experience that the slope detectors can, and often are, fooled under a variety of circumstances, most notably, recent consumption or regurgitation of an amount of alcohol, similar to what would occur during GERD emanation, which has a tendency to deposit alcohol-laden air in the oral cavity.
I have routinely observed the slope detector fail to register mouth alcohol that is as much as 12-15 minutes old, often allowing the unit to register an abnormally high reading given a simple swish of alcohol. Published studies indicate failure of the residual alcohol detection system to identify mouth alcohol bias between 37% (Harding et al, 1992) and 48 % failure (Simpson et al, 2004). Gullberg (2000) also reports on the inadequacy of the mouth alcohol detection systems. Harding reported that some of these failures occurred after more than 15 minutes of deprivation.
Since GERD contamination may not necessarily follow the “rise and drop” pattern, slope detection cannot be considered reliable enough to identify an invalid test result. Observation and deprivation periods must be carried out, closely and continuously, with breath test subjects who identify a history of GERD. Replicate testing should be performed. Indeed, blood testing should be offered as a preferred forensic alcohol testing method in persons with a known, medically diagnosed history of GERD.
Practice Tip: |
Final thoughts:
The percentage of reported false-positive BrAC versus BAC readings seems too high (30%) to be simply dismissed as inconsequential. We see routine false-positive BrAC results adding as much as 0.105 grams/210L. Certainly more research seems appropriate. The researchers cited seem reluctant to ascribe GERD as a causal factor because the instances of elevated BrAC reading occurred during the absorptive phase, when differences in arterial and venous blood alcohol concentrations are known to create a blood to breath partition lower than 2100:1, thereby over-reporting the BrAC reading.
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For further study:
- Booker, J. L., and Renfroe, K., The Effects of Gastroesophageal Reflux Disease on Forensic Breath Alcohol Testing, The Journal of Forensic Sciences, 2015.
- Chen, S., Wang, J. and Li, Y., Is Alcohol Consumption Associated with Gastroesophageal Reflux Disease?, Journal of Zhejiang University Science B., 2010 June; 11(6): 423-428, Zhejiang University, 2010.
- Hlastala, M., Lam, W., and Nesci, J., The Slope Detector Does Not Always Detect the Presence of Mouth Alcohol, For the Defense, March 2006.
- Gullberg, R., Breath Alcohol Analysis in One Subject with Gastroesophageal Reflux Disease, Case Report, Journal of Forensic Sciences, Vol. 46 No. 6, pages 1498-1503, 2001.
- Hiltz, S., et al, American Gastroenterological Association Medical Position Statement of the Management of Gastroesophageal Reflux Disease, Gastroenterology 2008; 135: 1383-1391, 2008.
- Jones, A.W., Breath Tests for Alcohol in Gastroesophageal Reflux Disease, Annals of Internal Medicine, Vol 130, Number 4 (Part 1), 1999.
- Jones, A.W., Reflections on the GERD Defense, DWI Journal: Law & Science, 20; 3-9, 2005.
- Jones, A.W., Gastric Reflux, Regurgitation, and the Potential Impact of Mouth-Alcohol on the Results of Breath-Alcohol Testing, DWI Journal: Law and Science 22; 1-8, 2007.
- Kahrilas, P., Gastroesophageal Reflux Disease, New England Journal of Medicine, 2008 October 16; 359(16): 1700-1707, October 2008.
- Kaufman, S. and Kaye, M., Induction of Gastro-Oesophageal Reflux by Alcohol, Gut, 1978, 19, 336-338, 1978.
- Kechagias, S., Jonsson, K-A, Franzen, T., Andersson, L and Jones, A.W., Reliability of Breath-Alcohol Analysis in Individuals with Gastroesophageal Reflux Disease, Journal of Forensic Sciences, 1999; 44(4): 814-818.
- McCallum R, Sabu J.G: Gastroparesis. Clinical Perspectives in Gastroenterology May/June 2001 pg. 147-154
- Scott, M, and Gelhot, A., Gastroesophageal Reflux Disease: Diagnosis and Management, American Family Physician, March 1999.
- Sifrim, D., Silny, D., Holloway, R. and Jansens J., Patterns of Gas and Liquid Reflux During Transient Lower Oesphageal Sphincter Relaxation: A Study Using Intraluminal Electrical Impedance, Gut 1999; 44:47-54, 1999.
- Wells, D. and Farrar, J., Breath-Alcohol Analysis of a Subject with Gastric Regurgitation, 11th International Conference on Alcohol, Drugs, and Traffic Safety, Chicago, 1999.
