Prevalence of alcohol and drugs in second sample blood specimens from potentially impaired drivers in the Commonwealth of Virginia, 2001--2002

Driving Under the Influence of Alcohol and/or Drugs has been an issue of public safety for many years. Studies have been performed to determine alcohol content in driver's blood. However, limited research has been performed to determine which drugs maybe present in drivers. The purpose of this research study was to identify if drugs were present, the blood concentration of the drug if identified, and any potential trends in drug use in drivers who had been arrested for suspected "driving under the influence of alcohol and/or drugs" in the Commonwealth of Virginia. The study attempted to identify the incidence of multiple drugs being present (single agent versus multi-drug use or abuse) in a driver that was arrested for a DUID offense. The study also attempted to determine if there was a blood alcohol concentration observed where alcohol was the only drug detected in the driver's blood sample at the time of arrest. From July 1, 2001 through December 31, 2002, 2948 blood samples from drivers who had been arrested for impaired driving, and had requested an independent analysis of their blood sample, were received and analyzed for blood alcohol content, and screened and quantitated for various illicit, prescription, and over the counter drugs. Presumptive positive results from the screening methods were qualitatively identified and quantitated. Initial screening was performed by immunoassay for assays that were commercially available (amphetamines, barbiturates, benzodiazepines, cannabinoids, cocaine, and opiates). Other screening was performed by gas chromatography or gas chromatography mass spectrometry. Alcohol was the most common drug detected, followed by cannabinoids, benzodiazepines, opiates, and cocaine. In approximately ½ of the samples, alcohol was the only drug detected. One in three samples contained 2 or more drugs, which may have impaired the driver's ability to operate a motor vehicle. Two or more drugs were detected throughout the range of blood alcohol concentrations. The range of drug concentrations from samples collected in 2001--2002 were compared to samples collected from 1990--1999. The concentration range of specific drugs detected did not change significantly between the two sample groups. The only significant change observed was that the average number of yearly samples received appeared to have increased ∼250 % per year.