Review: Drug concentrations in hair and their relevance in drug facilitated crimes.

Segmental hair analysis can provide valuable retrospective information on the history of drug exposure in victims of drug facilitated crimes (DFC). This is now possible with availability of sensitive tandem MS techniques such as GC-MS/MS and LC-MS/MS allowing drugs to be detected at pg/mg concentrations after a single dose. In this review hair concentrations of 35 psychoactive drugs given in 20 controlled dose studies are reviewed and compared to the 25 different drugs detected in reported case work. The most common drugs were the benzodiazepines and related hypnotics, gamma-hydroxybutyrate (GHB), ketamine and methamphetamine. Those concentrations reported in DFC were mostly similar or higher than that seen in controlled dose studies. The factors that affecting interpretation of segmental hair results including hair color, growth rates, sample preparation and surface contamination are discussed.