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Citation
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Kriikku P, Wilhelm L, Jenckel S, Rintatalo J, Hurme J, Kramer J. Toxichem Krimtech 2013; 80(Spec Iss): 312-314. |
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Abstract
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AIMS: This study compared results from the initial, roadside breathalyzer test performed by a police officer with the results of analysis of a blood sample collected some time later if the roadside breathalyzer indicated alcohol over the legal limit in Finland (0.50 g/L).
METHODS: All blood samples from drivers in Finland suspected of driving under the influence of alcohol in a three month period were included. For this comparison, elimination rates of 0.10 & 0.25 g/L*h were used to extrapolate upper and lower limits of the breath alcohol con- centration at the time of blood collection (=theoretically estimated BAC range).
RESULTS AND DISCUSSION: There were 1900 cases in which both a breathalyzer result and a blood analysis were available. Mean (range) blood alcohol content (BAC) was 1.92 (0.10- 4.60) g/L. Mean (range) breath alcohol content (BrAC) converted to the equivalent BAC in the screening measurement was 1.72 (0.10-5.54) g/L. In 52.4% of the cases the difference between the theoretically estimated BAC range and the measured BAC was more than 0.25 g/L. In 4.8% of the cases the difference was more than 1.00 g/L. The differences were more prevalent in higher concentrations well over the legal limit. In 6 cases the driver was under the legal limit on the breathalyzer but over the limit on blood analysis.
CONCLUSION: The large differences seen in this study may be due to e.g. problems in obtaining end-expiratory breath, operator error or breathalyzer calibration problems. Environmental conditions such as outside temperature and humidity may also affect breathalyzer results. It is crucial that all parties fully understand that road-side breathalyzer results are only suggestive and that a legally valid confirmatory test is required.
Language: de |