Hair analysis in workplace drug testing and driving licence regranting as a tool to disclose patterns of drug use

Background: In Italy, hair analysis is used in the second level-tests of workplace drug testing (WDT) protocol and for driving licence regranting/renewal (DLR). The WDT National Protocol includes two-level tests. The second level of the protocol is required when in the first level-tests urine sample results positive. In this case, the worker is obliged to go to the Public Drug Treatment Unit to undergo an eventual diagnosis of drug dependence. The second level-tests consist of analysing both urine and hair for opiates, cocaine, amphetamines, cannabinoids, methadone and buprenorphine. As far as driving licence regranting/renewal is concerned, subjects are instead always obliged to undergo toxicological analyses if they have either a documented past or a suspect present history of drug abuse, ( art. 187 “Driving under influence of drugs”), or if they are forced by the prefecture or by the traffic control authority. In some Regions such as Lombardy, hair analysis is used to rule out illicit drug use. This study presents the data obtained from hair analysis performed in the Laboratory of Forensic Toxicology of the University of Pavia in the last two years. Method: A total of 1017 hair samples were analysed for WDT (322) and DLR (695). Analyses were carried out by GC-MS using the method routinely applied on hair samples. Results and Discussion: The positive rate for the WDT second leve-test was 45% versus the 10% for the DLR. The different percentage of positive results demonstrate how hair analysis is useful both for the diagnosis of drug dependence and as deterrent of drug consumption. As regard to positive results distribution, a cocaine abuse emerged in 74.6% of workers, while drivers resulted positive mainly for cannabinoids (41%), and cocaine (39%). On the contrary, the second main consumption in WDT analysis resulted the polydrug abuse (16,5%). Opiates percentage was 1.4% in both cases while positive samples for methadone were 9 in the DLR analysis versus 3 in the WDT one. MDMA was present only in two workers and in association with cocaine.