Citation

Wigmore JG, Wilkie MP. J. Can. Soc. Forensic Sci. 2002; 35(1): 9-16.

Copyright

(Copyright © 2002, Canadian Society of Forensic Science, Publisher Informa - Taylor and Francis Group)

DOI

10.1080/00085030.2002.10757532

PMID

unavailable

Abstract

After consuming lunch, twenty-six male subjects ingested alcohol ad libitum over approximately one hour. At least 1.5 hours after drinking ceased, the subjects provided breath samples into a Breathalyzer® Model 900 or 900A. Immediately after providing the breath samples, blood was collected from the cubital vein using a sterile disposable plastic syringe. Part of the blood sample (3-10 mL) was placed into a blood tube containing 1 % sodium fluoride and 0.5 % sodium citrate and was analysed for alcohol by headspace gas chromatography. The remaining blood (3-10 mL) was placed in the subject's mouth for up to 30 seconds and then swallowed or expectorated. A second Breathalyzer test was conducted within ten minutes of the first. The blood alcohol concentrations of the subjects averaged 0.095 g/dL and ranged between 0.044 to 0.168 g/dL. The untruncated Breathalyzer results were significantly lower after introducing blood into the mouth (p=0.017). When these Breathalyzer results were truncated to two decimal places, however, these slight differences were eliminated. In addition, when the initial Breathalyzer results were compared to the blood alcohol concentrations the apparent blood breath ratios averaged 2319, with a range of 1947:1 to 2654:1. We conclude that blood in the mouth does not lead to an overestimation of the breath alcohol concentration of drinking subjects.