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Determining an appropriate protocol for the laboratory

المؤلف:  Sue Jickells , Adam Negrusz (Editors)

المصدر:  Clarkes Analytical Forensic Toxicology

الجزء والصفحة:  320

2026-10-28

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Determining an appropriate protocol for the laboratory

While attention should be paid to the opinion of the arresting officer about what drugs are suspected in any given case, the toxicologist should apply a good broad-spectrum drug screen to be able to exclude the possibility of other drugs with similar effects. For example, an individual withdrawing from intravenous amfetamine use may appear drowsy and have constricted pupils, poor psychomotor performance and injection marks. These symptoms may appear to be caused by a narcotic analgesic, and consequently a test only for opiates would not disclose the true agent responsible. The class of CNS depressants is probably the most challenging analytically, since it includes some chemically very diverse drugs, from solvents and inhalants to long- and short-acting benzodiazepines, antidepressants, antihistamines and novel recreational drugs such as gamma-hydroxybutyric acid and butane-1,4 diol. Practically speaking, an escalation approach is the most economical and effective, beginning with the commonly encountered drugs and expanding and adding assays for drugs that could account for the symptoms observed. It is critical that laboratories performing this work observe accepted standards for forensic analysis, including: maintaining security and chain of custody, maintaining written protocols for commonly performed procedures, validating method accuracy through use of appropriate standards and controls, verifying the identity of any drugs reported, using MS wherever possible, implementing the scientific review of data, participating in proficiency testing programmes and ensuring that staff have appropriately documented qualifications and training.