Patterns in drug use in the United Kingdom as revealed through analysis of hair in a large population sample.

This paper presents an overview of the most common sectioning patterns utilised in the analysis of hair for drug use; report on the major user groups (sectors) that currently make use of hair analysis in the United Kingdom (UK); present the results for the different drug groups analysed in samples of hair samples analysed at TrichoTech between 2001 and 2005. A total of 186,084 tests on 34,626 hair samples were performed for the commonly requested drug groups. There were 145,799 enzyme-linked Immunosorbent positive screening tests (ELISA), which were subsequently confirmed by gas chromatography equipped with mass spectrometry detection (GC-MS). The two major sectors were the Medico-Legal sector (65%) and Workplace (20%). Police (Forensics), Clinical Monitoring, Schools, Research and Insurance accounted together for the remaining 15% of the samples. Combinations of several sections patterns were requested covering periods from the most recent month up to 24 months. The most common sectioning pattern was one single section measuring 3 cm, to cover the most recent 3 months (44%), which in some cases was complemented by a further 3 cm to cover together 6 months (13%). The second most common sectioning pattern was the analysis of three sections of 1cm each to cover the most recent 3 months (28%), when a more detailed evaluation of drug use pattern was relevant. Samples collected from other areas of the body such as axilla, pubic, chest, beard and leg, constituted 6% of the samples. The analysis of monthly sections plays an important role in the evaluation and interpretation of drug use, particularly in certain Medico-Legal cases. The sectors with the highest rates of positive results were Police (Forensics) (78%), Medico-Legal (62%) and Clinical (54%). The common drugs in each group were cannabinol (27%), cocaine (25%), morphine (17%), amphetamine (13%) and diazepam (15%). The positive rate for the Workplace sector was 10%. The most common drugs detected in the Workplace samples in each group were: THC (4%), codeine (2%), cocaine (2%), MDMA (0.5%) and diazepam (0.1%). The concentration levels of drugs found in samples from the workplace were lower than in the other sectors (95% of cases). The exceptions were for dihydrocodeine and MDMA, where levels were 170 and 143% higher, respectively. However, the maximum levels detected in the Workplace samples were lower. The Medico-Legal sector is the most prevalent sector using hair analysis in the UK but the rate of Workplace sector use of hair testing is increasing. One in 10 workplace hair tests detected the presence of at least one drug, which is twice the rate of detection using urine, which is a 1 in 20 urine sample. This means that the chances of identifying people on drugs in the workplace by testing hair samples are twice as likely than urine samples.