Mary McMurray on BrAC testing

There is a BrAC expert that I personally have a great amount of respect for. Her name is Mary McMurray. She took a post from “IFuckingLovScience” Facebook page and repurposed it for BrAC testing. I personally think it is hilarious, not because of its content, but because it is true. The truth is funnier than fiction.

How you can tell Pseudoscience when you see it:

What to look out for The “claim” Source
Exaggerated claims The partition ratio for ethanol is 2100:1.  Breath-temperature is 34° Celsius. State Breath Alcohol Operator Training manuals all across the US
Over-reliance on anecdotes “The results presented will be useful to rebut defense arguments that focus on GERD as a medical condition that might compromise the application of breath-alcohol instruments for workplace alcohol testing and in traffic law enforcement.” Reliability of Breath-Alcohol Analysis in Individuals with Gastroesophageal Reflux Disease   Kechagias, et. al. j. Forensic Sci 1999; 44(4): 814-818
Absence of connectivity to other research The gas exchange for alcohol occurs deep within the lungs in the alveolar sacs State Breath Alcohol Operator Training manuals all across the US
Lack of review by other scholars (called peer review) or replication by independent labs “We conclude that the risk of a person experiencing gastric reflux during the time he or she participates in a breath-alcohol test 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.” Reliability of Breath-Alcohol Analysis in Individuals with Gastroesophageal Reflux Disease   Kechagias, et. al.; J Forensic Sci 1999; 44(4): 814-818
Lack of self-correction when contrary evidence is published “The most practical argument against cornstarch and talcum powder interfering with the breath test is the fact that cornstarch and talcum powder are highly absorbent; they adhere to the mucus lining of the respiratory system, are non-volatile and are eventually eliminated from the respiratory system by ciliary movement of the mucus to the mouth, not by exhalation.” The Tyndall Effect in the Intoxilyzer 5000 “The Airbag Defense”    Seth Craig; IACT Newsletter 2004; 15(2): 13-15
Meaningless “psychobabble” that uses fancy scientific-sounding terms that don’t make sense “Theoretically, hyperthermia should increase the partial pressure of alcohol in the vapor phase form the blood, resulting in an increase in the breath alcohol concentration (BrAC), whereas hypothermia should lower the partial pressure of alcohol in the vapor phase from the blood, resulting in a decrease on the BrAC. In vitro blood experiments have shown that for every 1.0° C change in the temperature of the blood, a corresponding change of approximately 6.5% occurs in the concentration of the alcohol in the vapor in equilibrium with the blood.” The Relationship of Normal Body Temperature, End-Expired Breath Temperature, and BAC/BrAC Ratio in 98 Physically Fit Human Test Subjects    Cowan, et. al.; J Analytical Tox 2010; 34(June): 238-242
Talk of “proof” instead of “evidence” Every person, regardless of that person’s experience with alcohol beverage consumption is impaired in driving performance if that person’s alcohol concentration is 0.08 or more. Research indicates that the ability of many individuals is impaired for driving and driving related tasks at alcohol blood or breath concentrations below 0.08, and that for some individuals impairment occurs at alcohol concentrations below 0.05. Therefore, at alcohol concentrations below 0.05, no statutory presumption regarding the presence or absence of alcohol influence should be made. National Safety Council Policy #58
 

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