Cannabinoid concentrations in hair from documented cannabis users

Area of Science:

• Forensic Toxicology
• Pharmacology
• Analytical Chemistry

Background:

• Cannabis use is prevalent, and reliable drug testing methods are crucial for legal and clinical settings.
• Hair analysis offers a long detection window for drug use compared to urine tests.

Purpose of the Study:

• To evaluate the detection rates and concentrations of delta9-tetrahydrocannabinol (THC) and its metabolite 11-nor-9-carboxy-THC (THCCOOH) in head hair specimens.
• To compare detection rates between daily and non-daily cannabis users.
• To assess the correlation between THC and THCCOOH concentrations in hair.

Main Methods:

• Collected 53 head hair specimens from 38 males with documented cannabis use.
• Utilized questionnaires and urinalysis to confirm cannabis consumption.
• Administered delta9-tetrahydrocannabinol (THC) under controlled conditions.
• Analyzed hair specimens using Enzyme-Linked Immunosorbent Assay (ELISA) and Gas Chromatography-Mass Spectrometry/Mass Spectrometry (GC-MS/MS).

Main Results:

• 36% of specimens showed no detectable THC or THCCOOH.
• Detection rates were significantly higher in daily users (85%) versus non-daily users (52%).
• THC and THCCOOH concentrations were positively correlated (r=0.38).
• 83% of immunoassay-positive screens were confirmed by GC-MS/MS.

Conclusions:

• Hair analysis is effective in detecting chronic and occasional cannabis use.
• Detection rates are significantly influenced by the frequency of cannabis consumption.
• GC-MS/MS provides reliable confirmation of cannabinoids in hair specimens.