Drivers under the influence of drugs of abuse: quantification of cocaine and impaired driving.

In recent years, the interest in oral fluid as a biological matrix has significantly increased, particularly for detecting driving under the influence of drugs. In this study, the concentration of cocaine and its relationship with clinical symptoms in drivers suspected of driving under the influence of drugs was evaluated. A total of 154 samples of oral fluid, which tested positive for cocaine in previous immunoassay screening, Cozart Drug Detector System, were confirmed using gas chromatography/mass spectrometry method. In Catalonia, during 2007-2010, there were 1791 samples positive for cocaine among a total of 3468 samples taken from drivers who tested positive for any drug of abuse. The evaluation of clinical symptoms was through a questionnaire that was filled in by the police officers who collected the samples. The mean concentration of cocaine was 4.11 mg/l and median concentration was 0.38 mg/l (range 0.01-345.64 mg/l). Clinical impairment symptoms such as motor coordination, walking, speech, mood and state of pupils were not significant. The testing of oral fluids presents fewer ethical problems than blood or urine.

Applicability of an on-site test for its use in post-mortem blood.

The number of deaths related to drugs of abuse makes necessary the use of an on-site test for those cases in which a rapid detection of the consumed drug is required. Cozart® DDS test provides a simple, fast and reliable tool for the qualitative on-site analysis in post-mortem blood. Owing that this test is prepared for oral fluid samples, a validation becomes essential in order to use it for a different matrix than the established one. According to that, results obtained by Cozart® DDS test used in post-mortem blood samples have been compared with a qualitative gas chromatography-mass spectrometry (GC/MS/MS). Positive results for cocaine family compounds (COC-F) were 43.75%, for opiates family compounds (OPI-F) 25.78%, and for cannabis family compounds (THC-F) 2.34%. Negative results were 28.13%. No amphetamines (AMP) or methamphetamines (MA) were found. Sensitivity and specificity was available for cocaine and opiates but not for cannabis because only five cases were detected. Sensitivity, specificity, predictive positive value and predictive negative value for cocaine were 98%, 91%, 88% and 99%, respectively. Sensivilty, specificity, predictive positive value (PPV) and predictive negative value (NPV) for opiates were 93%, 92%, 76% and 98%, respectively. Likelihood positive ratios for cocaine and opiates have been 10.92 and 11.69, respectively, while likelihood negative ratios have been 0.02 and 0.08, respectively. Results show the suitability of Cozart® DDS test for the qualitative detection of cocaine and opiates in post-mortem blood.