Drugs are incorporated into growing hair and therefore the analysis of a sample of hair can be used as a tool to help demonstrate retrospective abstention. It should be noted however that a time delay of up to several weeks can elapse before drugs appear in hair.
A sample of hair (roughly the width of a thin pencil) is taken from the back of the crown of the head. Obviously a sufficient length of hair must be available before a hair test can be carried out; at least 2 cm should be available for collection, which would enable 2 months retrospective drug abuse screening to be carried out. The usual length of head hair analysed is 3 cm (proximal) – representing the previous 3 months approximately.
Body hair may also be used (eg pubic, underarm or chest). Generally body hair samples are analysed as a single entity and reflect a longer detection period – up to approximately 6 months or more. Due to the growth patterns of body hair, segmental analysis is not possible.
NIVHA provides a complete service: from sample collection, laboratory analysis and expert interpretative report for court purposes.
All analytical work is accredited to UKAS 17025 standard.
The standard drug panel represents a broad range of commonly abused drugs:
- Ecstasy drugs (eg MDMA)
- Opiates (morphine, codeine, dihydrocodeine)
- Cannabis (THC)
- Benzodiazepines (eg diazepam, temazepam)
Additional drugs can also be added if required.
Hair collection and analysis for drugs follows international guidelines established by the Society for Hair Testing (www.SOHT.org).