Evaluation of breath alcohol analysers by comparison of breath and blood alcohol concentrations
The main goal of this study was to determine the reliability of hand-held breath alcohol analysers currently approved for roadside screening of traffic offenders. The first part of the study included a retrospective data analysis of 714 offence records collected in 2011. Blood alcohol concentrations (BAC) obtained from the offenders 0-303 min after the police had screened them for breath alcohol concentration (BrAC) were back-calculated (cBAC) to assess the accuracy of breathalyser screening. All participants were in the alcohol elimination phase, and our analyses did not reveal any significant differences between cBAC and BrAC. To verify our findings, we performed a controlled drinking study that involved 63 healthy volunteers who consumed alcoholic beverages to simulate real drinking conditions. Immediately after alcohol consumption, BrAC was determined with a Dräger breath alcohol analyser model 6810, and 29 participants gave blood and urine sample for concomitant BAC analysis one hour later. BAC and urine alcohol concentrations were determined with headspace gas chromatography. Again, we found no significant differences between BrAC and BAC. These results confirmed the high reliability of breath alcohol analysers for measuring BrAC as long as police officers perform the measurements according to the manufacturer’s instructions.