Does Bacterial Overgrowth Affect Breath Alcohol Levels on DUI Testing?: 2016 ACG Presidential Poster Award

Abstract

Introduction: Breath alcohol concentration (BrAC) has long served as critical evidence in a driving under the influence (DUI). Recently a defense expert witness stated that hydrogen due to maladies such as small intestinal bacterial overgrowth (SIBO) could affect BrAC by interaction with its fuel cell. In addition, a recent legal case of “auto-brewery syndrome” highlighted the potential for gut bacteria to produce alcohol during fermentation. In this study, we assess the risk of detectable BrAC or hydrogen interfering with sensors due to bacterial overgrowth using DUI instruments. Methods: In collaboration between the Los Angeles Police Department forensic division and a tertiary care medical center, patients referred for lactulose breath testing provided informed consent to participate. Breath samples were collected using Quintron dual-bag gas collection system (Quintron Diagnostics, Milwaukee, WI) at baseline and every 15 minutes for up to 2 hours after 10g lactulose ingestion. Breath samples were analyzed for hydrogen and methane after correction for CO2 levels using a Quintron BreathTrackerTM gas chromatograph. Simultaneous to breath collection, subjects were asked to exhale into an Intoximeter EC/IR II (Intoximeters, Inc, St Louis, MO). Results of breath hydrogen, methane, and alcohol were compared. Results: Fifty subjects were recruited [29 F, mean=44±18 yrs, range 18-83], most who were referred for symptoms including bloating, diarrhea, constipation and abdominal pain. Three of the patients elected to decline participation, of which two provided at least one BrAC collection with no BrAC detected. Of the remaining 47 subjects, 25 (53%) were hydrogen positive (range=1-176 ppm) and 11 had detectable methane (>3ppm, range=0-107 ppm). Despite these breath test abnormalities, all but one patient in this study had no detectable BrAC (0.000g/210L) at any point during breath testing. The single exception presented with a baseline BrAC of 0.026g/210L and admitted to drinking heavily the night before. During the following 2 hours, the BrAC steadily declined to 0.000g/210L. Conclusion: This very important study refutes the claim that patients producing hydrogen in their breath produce a false positive BrAC result. Moreover, hydrogen does not create a chemical reaction capable of causing a voltage charge on the fuel cell to produce a positive BrAC reading. In addition, SIBO is a not a common source of alcohol and is not likely to cause intoxication or positive DUI test.