title: Detection of illicit drugs in oral fluid from drivers as biomarker for drugs in blood.
abstract: OBJECTIVE
  To assess whether analysis of oral fluid can be used to identify individual drivers with drug concentrations in blood above 25ng/mL for amphetamine and methamphetamine, 10ng/mL for cocaine and 1.0ng/mL for tetrahydrocannabinol (THC), which are the cut-off concentrations used in the European DRUID Project, by calculating the diagnostic accuracies when using the analytical cut-off concentrations in oral fluid as well as for the optimal cut-off concentrations.
  
  
  METHODS
  Paired samples of whole blood and oral fluid collected with the Statsure SalivaSampler were obtained from 4080 drivers in four European countries and analysed for amphetamine, methamphetamine, cocaine and THC using GC-MS or LC-MS. The vast majority (89%) were random drivers not suspected of drug-impaired driving. Receiver-Operating Characteristic analysis was used to evaluate the analytical results.
  
  
  RESULTS
  The prevalence of drug findings above the cut-off concentrations in blood was 1.3% for amphetamine, 1.0% for methamphetamine, 0.6% for cocaine and 1.3% for THC. The cut-off concentrations in oral fluid that gave the highest diagnostic accuracy were for amphetamine 130ng/mL (accuracy 99.8%), methamphetamine 280ng/mL (accuracy 99.9%), cocaine 570ng/mL (accuracy 99.6%), and THC 38ng/mL (accuracy 98.3%). The proportion of false positives were 0.2%, 0.1%, 0.1% and 0.9%; and the proportion of false negatives were 0.1%, 0.0%, 0.3% and 0.8%, respectively, when using those cut-offs. The positive predictive values were 87.9%, 92.9%, 84.6% and 35.7% for amphetamine, methamphetamine, cocaine and THC, respectively.
  
  
  CONCLUSIONS
  Analysis of concentrations of illicit drugs in oral fluid could not be used to accurately identify drivers with drugs concentrations above the selected cut-offs in blood in a cohort of drivers with low prevalence of drugs.
authors: Division of Forensic Sciences, Norwegian Institute of Public Health, Oslo, Norway. Electronic address: hallvard.gjerde@fhi.no.
authors: Hallvard
authors: H
authors: Gjerde
authors: National Institute for Health and Welfare, Helsinki, Finland.
authors: Kaarina
authors: K
authors: Langel
authors: Department of Public Health and Environmental Medicine, Forensic Toxicology and Antidoping Unit, University of Padova, Padova, Italy.
authors: Donata
authors: D
authors: Favretto
authors: Department of Clinical Chemistry, Microbiology and Immunology, Ghent University and Department of Laboratory Medicine, Ghent University Hospital, Ghent, Belgium.
authors: Alain G
authors: AG
authors: Verstraete
mesh_terms: D000661:Amphetamine / Q000032:analysis; D015415:Biomarkers / Q000737:chemistry; D003042:Cocaine / Q000032:analysis; D000066448:Driving Under the Influence; D013759:Dronabinol / Q000032:analysis; D005060:Europe; D053593:Forensic Toxicology; D006801:Humans; D013287:Illicit Drugs / Q000032:analysis*; D008694:Methamphetamine / Q000032:analysis; D011237:Predictive Value of Tests; D012463:Saliva / Q000737:chemistry*; D012680:Sensitivity and Specificity; D015813:Substance Abuse Detection / Q000379:methods*; D019966:Substance-Related Disorders / Q000175:diagnosis
chemical_list: D015415:Biomarkers; D013287:Illicit Drugs; D008694:Methamphetamine; D013759:Dronabinol; D000661:Amphetamine; D003042:Cocaine
keywords: Blood; False negatives; False positives; Illicit drugs; Oral fluid; Positive predictive value