URINE TOXICOLOGY SCREENS IN DRIVERS SUSPECTED OF DRIVING WHILE IMPAIRED FROM DRUGS

Objective: Police departments, in conjunction with the National Highwa y Traffic Safety Administration, have developed a standardized evaluat ion aimed at identifying drivers impaired by drugs other than ethanol. These evaluations are performed by specially trained police officers known as Drug Recognition Experts. Methods: We retrospectively reviewe d the evaluations of 242 drivers detained for driving while impaired i n the City and County of Denver from January 1, 1988 to June 30, 1990. Results: All drivers had urine toxicology screens performed, which we re positive for a mean 1.2 +/- 0.9 SD (range zero to four)for drugs ha ving the potential for causing driving impairment. The 193/242 urine s creens (79.8%) testing positive showed the following drugs: cannabis 1 62 (66.9%), stimulants (including cocaine metabolites) 80 (33.1%), dep ressants (benzodiazepines and barbiturates) 24 (9.9%), narcotics 12 (5 .0%), inhalants (toluene) 1 (0.4%), hallucinogens (LSD) 1 (0.4%), and other 3 (1.2%). Drug Recognition Experts, based on their initial evalu ation, were able to predict correctly some or all of the drugs found o n the urine screens in 178/242 (73.6%) of cases. Overall agreement bet ween the Drug Recognition Experts opinions and urine screen results ha d a kappa value (p < 0.05) of 0.41. Conclusions: There was a high rate (79.8%) of positive urine toxicology screens in drivers suspected of nonethanol drug impairment. In most cases, Drug Recognition Experts we re able to reliably predict the results of these screens.