title: Utility of coloured hair for the detection of drugs and alcohol.
abstract: The aim of this paper is to assess the utility of coloured hair for the detection of drugs and alcohol in a large statistically significant population. The positivity rate, the 1st, 5th, 50th, 95th, and 99th percentiles of five amphetamines, cannabinoids, cocaine, four opiates, methadone, buprenorphine, seven benzodiazepines, and ethyl glucuronide (EtG) in 9488 non-treated and 1026 cosmetically treated (dyed or bleached) authentic hair samples was compared. Analytical methods used were accredited for forensic purposes at the cut-offs defined by the German driving licence re-granting medical and psychological assessment (MPA) guidelines. Considering only the drug classes for which at least 10 positive samples were detected, the positivity rate in non-treated hair was highest for alcohol (4.50%; measured using EtG at concentrations ≥ 7 pg/mg hair), followed by THC (2.00%), cocaine (1.75%), and amphetamine (0.59%). While the 1st to 99th percentile range was significantly lower for drugs in treated, compared to non-treated hair, no significant change was observed for EtG. Additionally, no significant difference in the positivity rate was observed between treated hair and non-treated hair for both drugs and EtG. This study is the first attempt to evaluate the influence of cosmetic treatment, mainly dying, on the positivity rate for both drugs and EtG in hair samples submitted routinely for abstinence testing and the first to indicate that dyed and eventually bleached hair is not necessarily useless in detecting drugs and/or alcohol consumption, thus making coloured hair analysis still useful, often being the only possibility to prove such misuse.
authors.affiliation: Department of Forensic and Clinical Toxicology, Siemensstraße 40, 32105 Bad Salzuflen, Germany.
authors.forename: Ronald
authors.initials: R
authors.lastname: Agius
mesh_terms: D000431:Ethanol / Q000032:analysis*; D006197:Hair / Q000737:chemistry*; D006202:Hair Dyes / Q000737:chemistry*; D006801:Humans; D013287:Illicit Drugs / Q000032:analysis*; D015813:Substance Abuse Detection / Q000379:methods*
chemical_list: D006202:Hair Dyes; D013287:Illicit Drugs; D000431:Ethanol
keywords: EtG; bleaching; cosmetic treatment; driving licence; drugs; dyeing; hair; percentiles