Experience with hair testing in the clinical biochemistry laboratory of Ca' Granda Niguarda Hospital, Milan, Italy

Abstract

In our laboratory, analysis of human hair for drugs of abuse detection was first performed in 1980. In the last 10 years we have processed about 2000 subjects/year (‘living subjects’ only). In the last 3 years we have also introduced hair analysis of cocaine: at first only in clinical applications, but for the last 2 years this analysis is now routine. Our application of hair analysis includes: clinical toxicology, medico-legal and administrative agencies. Requests come for example from several Committees for Driving Licenses, Addiction Treatment Centers and Legal Authorities. Hair samples are currently collected from the occipital area at the back of the head, which appears to show less variability in hair growth rate. At present we perform hair analysis using highly sensitive radioimmunoassay screening methods for the detection of parent drug and/or metabolites. All positive cases of cocaine and opiates abuse are confirmed by gas chromatography-mass spectrometry in electron impact or chemical ionization mode. Positive cases for opiates are also analysed using a specific morphine radioimmunoassay kit. Data show that, when the opiates/morphine ratio is higher than 6, we are dealing with consumption of codeine and/or dihydrocodeine. In our routine work last year there were 177 (263 samples) positive opiates subjects out of 2244 patients; positive cocaine subjects were 290 (362 samples) out of 2001 patients.Guidelines for hair analysis in Lombardia have been established based on the experience of our laboratory. Furthermore it will be possible to apply a unique protocol for all Committees for Driving Licenses, involving hair testing in addition to urine assay.