تسجيل الدخول

تسجيل

Sectional analysis

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  162

2026-10-05

158

Sectional analysis

Multisectional analysis involves taking a length of hair and cutting it into sections to measure drug use during shorter periods of time. The hair must be cut as close as possible to the scalp. Particular care is also required to ensure that relative positions of the pieces of cut hair are retained. The further away from the hair root, the more cautious the interpretation of the quantitative findings of the individual hair sections has to be. It has been claimed that this technique can provide a retrospective calendar of an individual’s drug use. For example, one can perform multisection analysis for people who test positive on an initial screen. This information can be used to validate an individual’s claim of prior drug use but abstinence during the most recent several months. Baumgartner et al. (1989) proposed that another use of such information is to compare the results with the individual’s self-reported drug-use history, to establish the level of abstention prior to referring the individual to rehabilitation. The most extensive study on sectional analysis for drugs of abuse involved patients in rehabilitation centres. Segmental hair analysis was used to verify both their previous drug history and their recent enforced abstinence. In case of abstinence the lowest drug concentrations are found in the segments nearest the root, thus confirming decreased drug use or recent abstinence. Abstinence from tobacco can be demonstrated by sectional analysis. The switch from heroin to another drug (codeine, ethylmorphine, dihydrocodeine) can be established with accuracy. Given the variation of hair-growth rates and the long half-lives of particular drugs (cannabinoids) which can be retained in the body for weeks or months, results from a multisectional analysis should not be used to determine a precise period of drug abuse or to compare drug taking in individuals.