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

• Single-dose studies are reviewed relative to reports on drug facilitated crimes (DFC).
• Twenty controlled single dose studies have been published on 35 drugs.
• Single doses can generally be detected in human hair.
• Most common drugs were benzodiazepines, GHB, ketamine and methamphetamine.
• Published DFC case studies show similar concentrations in hair to controlled dose studies.

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.