title: Comparison of breath-alcohol screening test results with venous blood alcohol concentration in suspected drunken drivers.
abstract: Hand-held electronic breath-alcohol analyzers are widely used by police authorities in their efforts to detect drunken drivers and to improve road-traffic safety. Over a three month period, the results of roadside breath-alcohol tests of drivers apprehended in Finland were compared with venous blood alcohol concentration (BAC). The mean (median) time between sampling blood and breath was 0.71h (0.58h) with a range from 0 to 6h. Some hand-held instruments gave results as the concentration of alcohol in breath and were converted into BAC assuming a blood-breath alcohol ratio (BBR) of 2260. The mean venous BAC (1.82g/kg) in traffic offenders was higher than the result predicted by the hand-held breath analyzers (1.72g/kg). In 1875 roadside tests, the relationship between venous BAC (x) and BrAC (y) was defined by the regression equation y=0.18+0.85x. The coefficients show both a constant bias (y-intercept 0.18g/kg) and a proportional bias (slope=0.85). The residual standard deviation (SD), an indicator of random variation, was ±0.40g/kg. After BAC results were corrected for the time elapsed between sampling blood and breath, the y-intercept decreased to 0.10g/kg and 0.004g/kg, respectively, when low (0.1g/kg/h) and high (0.25g/kg/h) rates of alcohol elimination were used. The proportional bias of 0.85 shows that the breath-alcohol test result reads lower than the actual BAC by 15% on average. This suggests that the BBR of 2260 used for calibration should be increased by about 15% to give closer agreement between BAC and BrAC. Because of the large random variation (SD±0.40g/kg), there is considerable uncertainty if and when results from the roadside screening test are used to estimate venous BAC. The roadside breath-alcohol screening instruments worked well for the purpose of selecting drivers above the statutory limit of 0.50g/kg.
authors.affiliation: Vita Laboratory, Helsinki, Finland; Department of Forensic Medicine, Hjelt Institute, University of Helsinki, Finland. Electronic address: pirkko.kriikku@helsinki.fi.
authors.forename: Pirkko
authors.initials: P
authors.lastname: Kriikku
authors.affiliation: LADR GmbH Medizinisches Versorgungszentrum, Geesthacht, Germany.
authors.forename: Lars
authors.initials: L
authors.lastname: Wilhelm
authors.affiliation: LADR GmbH Medizinisches Versorgungszentrum, Geesthacht, Germany.
authors.forename: Stefan
authors.initials: S
authors.lastname: Jenckel
authors.affiliation: National Bureau of Investigation Forensic Laboratory, Vantaa, Finland.
authors.forename: Janne
authors.initials: J
authors.lastname: Rintatalo
authors.affiliation: Vita Laboratory, Helsinki, Finland.
authors.forename: Jukka
authors.initials: J
authors.lastname: Hurme
authors.affiliation: LADR GmbH Medizinisches Versorgungszentrum, Geesthacht, Germany; Medical Department I, University of Lübeck, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Kramer
authors.affiliation: Department of Clinical Pharmacology, University of Linköping, Linköping, Sweden.
authors.forename: A Wayne
authors.initials: AW
authors.lastname: Jones
authors.affiliation: Department of Forensic Medicine, Hjelt Institute, University of Helsinki, Finland.
authors.forename: Ilkka
authors.initials: I
authors.lastname: Ojanperä
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000428:Alcohol Drinking / Q000453:epidemiology; D001334:Automobile Driving / Q000331:legislation & jurisprudence*; D001944:Breath Tests / Q000295:instrumentation*; D002492:Central Nervous System Depressants / Q000032:analysis*; D002849:Chromatography, Gas; D000431:Ethanol / Q000032:analysis*; D005260:Female; D005387:Finland / Q000453:epidemiology; D053593:Forensic Toxicology; D006801:Humans; D008297:Male; D008875:Middle Aged; D016495:Police; D012044:Regression Analysis; D015813:Substance Abuse Detection / Q000295:instrumentation / Q000379:methods*; D055815:Young Adult
chemical_list: D002492:Central Nervous System Depressants; D000431:Ethanol
keywords: Alcohol; Blood; Breath; Driving; Roadside screening; Traffic safety