Accuracy and precision are critical parameters in blood alcohol concentration (BAC) measurements, providing forensic toxicologists with optimal confidence in analytical results and allowing them to be fully prepared to withstand tough cross examination by defense attorneys. There are five different bodily samples that can be screened to determine a person’s BAC: namely urine, saliva, hair follicles, blood, and breath. Currently, breath analysis and blood screening are the most commonly used BAC measurement methods implemented by law enforcement agencies to gather evidence.
Blood alcohol testing is one of the most accurate methods for measuring a person’s BAC, enabling forensic toxicologists to determine the amount of alcohol that is in the blood at the time a blood sample is taken. However, blood alcohol testing is one of the most intrusive methods and is mainly used when a suspect has refused a breath test or following a serious accident.
Modern forensic toxicology laboratories need productivity and reliability to enable continuous 24/7 operations and allow the dependable quantitative determination of alcohol content in blood. In addition, this type of testing is strictly regulated, posing a further challenge to forensic toxicology laboratories that require advanced technology in order to comply with industry regulations.
In the U.S. all 50 states and the District of Columbia impose regulations, according to which it is a crime to drive with a BAC at or above a specified level which is currently 0.08 g alcohol per 100 ml blood. Conviction for alcohol impaired driving is normally followed by license suspension, while licenses can also be taken before conviction when a driver fails or refuses to take a chemical test. This is called administrative license suspension and is enforced in 41 states and the District of Columbia.
Additionally, more than half of the states require driving under the influence (DUI) and driving when intoxicated (DWI) offenders to install ignition interlocks on their vehicles into which they must exhale before being allowed to drive during a license suspension. In 15 states and four California counties, such a restriction is applied to all offenders, while another 16 states apply the restriction to offenders with a high BAC (typically 0.15% or higher) and to repeat offenders. Finally, six states apply the restriction only to repeat offenders.1
Each of the countries in the European Union has regulations in place to restrict the amount of alcohol allowed in the blood when driving. Driving under the influence of alcohol is a crime and can be punished by a fine and driving ban for a specified amount of time. The average BAC permitted across the majority of European countries, including Spain, Italy, and Ireland, is 0.05%, with some countries such as the United Kingdom allowing 0.08%.