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Simulation of the Effect of Blood in the Mouth on Breath Alcohol, Concentrations of Drinking Subjects

NCJ Number
194765
Journal
Canadian Society of Forensic Science Journal Volume: 35 Issue: 1 Dated: March 2002 Pages: 9-16
Author(s)
J. G. Wigmore; M. P. Wilkie
Date Published
2002
Length
8 pages
Annotation
This study investigated whether blood in the mouth (that contained alcohol) had the potential of elevating the results of a Breathalyzer test, which measures a person's breath alcohol concentration.
Abstract
At issue in some criminal courts in Canada and in Australia is a concern about residual alcohol in the mouth of drinking subjects. For example, if the person is involved in a car accident and suffers mouth injuries (or had dental work performed before the accident), what effect, if any, would blood in the mouth have on the results of the blood alcohol test administered? After eating lunch, 26 male subjects consumed alcohol for 1 hour. After 1 hour and 30 minutes, the cooperative participants provided breath samples and blood samples. About half of the blood drawn was placed in a blood tube with a mixture of 1 percent sodium fluoride and 0.5 percent sodium citrate and analyzed for its alcohol content. Breathalyzer technicians regularly truncate all breach alcohol results to two decimal places. The remaining blood was put into the participants' mouth, via a syringe, for up to 30 seconds, then swallowed or spit out. Within 1 minute, a second breath test was obtained. The results of the second test revealed a lower blood alcohol concentration than the first Breathalyzer test, but not enough of a difference when the findings were truncated to two decimal places. Even though blood in the mouth decreased the second test result, it was not statistically significant. Tables, figures, references