Integrated use of hair analysis to investigate the physical fitness to obtain the driving licence: a casework study

Abstract

According to the laws presently in force in Italy and the guidelines of the Driving Licence Enforcement Commission of Verona, applicants for the driving licence with a history of drug abuse undergo a medical examination, during which complete anamnestic and clinical data are recorded. On this occasion, a hair sample (50–200 mg) is collected and a urinalysis program is started consisting ofEMIT ® controls for opiates, methadone, cocaine, barbiturates, amphetamines, cannabinoids, benzodiazepines and alcohol carried out on eight seriate samples, collected at random over about 40 days under direct supervision. The positive results from urine immunoassays are confirmed by standardized GC/MS methods. The hair samples are screened for morphine and cocaine, the most abused illicit substances in our region, using commercial RIAs adopting cut-off levels of 0.1 ng/mg. All positive samples and about 10% of negative are confirmed by HPLC. In case of confirmed positive results, the applicant is informed: if the subject denies use of opiates or cocaine in the recent months, he or she has the chance of submitting for analysis a new hair sample, which is analyzed in parallel with the hair remaining from the previous assay. In case of persisting denial, claiming analytical interferences by other drugs or endogenous substances, further confirmation of results can be carried out by CE and/or by qualitative MS/MS. In addition, hair sampling from multiple sites (scalp, axillary, pubic hair) with different susceptibility to contamination from the external sources can be carried out to rule out the possibility of passive contamination. At present, we investigate more than 700 subjects per year. The results of this integrated diagnostic strategy are presented and discussed.