Cannabinoid concentrations in hair from documented cannabis users

• Published in: Forensic science international 2007-07, Vol.169 (2), p.129-136
• Main Authors: Huestis, Marilyn A, Gustafson, Richard A, Moolchan, Eric T, Barnes, Allan, Bourland, James A, Sweeney, Stacy A, Hayes, Eugene F, Carpenter, Patrick M, Smith, Michael L
• Format: Article
• Language: English
• Subjects: Adult; Bias; Biological and medical sciences; Chromatography; Cocaine; Criminal investigations; Double-Blind Method; Dronabinol - administration & dosage; Dronabinol - analogs & derivatives; Dronabinol - analysis; Drug abuse; Drug dosages; Drug use; Enzyme-Linked Immunosorbent Assay; Forensic medicine; Forensic sciences; Forensic Toxicology; Gas Chromatography-Mass Spectrometry; General aspects; Hair; Hair - chemistry; Hallucinogens - administration & dosage; Hallucinogens - analysis; Humans; Immunoassay; Investigative techniques, diagnostic techniques (general aspects); Male; Marijuana; Marijuana Abuse; Marijuana Smoking; Mass spectrometry; Medical sciences; Pathology; Public health. Hygiene; Public health. Hygiene-occupational medicine; Sex crimes; Studies; Substance Abuse Detection
• ISSN: 0379-0738; 1872-6283
• DOI: 10.1016/j.forsciint.2006.08.005

Abstract Fifty-three head hair specimens were collected from 38 males with a history of cannabis use documented by questionnaire, urinalysis and controlled, double blind administration of Δ9 -tetrahydrocannabinol (THC) in an institutional review board approved protocol. The subjects completed a questionnaire indicating daily cannabis use ( N = 18) or non-daily use, i.e. one to five cannabis cigarettes per week ( N = 20). Drug use was also documented by a positive cannabinoid urinalysis, a hair specimen was collected from each subject and they were admitted to a closed research unit. Additional hair specimens were collected following smoking of two 2.7% THC cigarettes ( N = 13) or multiple oral doses totaling 116 mg THC ( N = 2). Cannabinoid concentrations in all hair specimens were determined by ELISA and GCMSMS. Pre- and post-dose detection rates did not differ statistically, therefore, all 53 specimens were considered as one group for further comparisons. Nineteen specimens (36%) had no detectable THC or 11-nor-9-carboxy-THC (THCCOOH) at the GCMSMS limits of quantification (LOQ) of 1.0 and 0.1 pg/mg hair, respectively. Two specimens (3.8%) had measurable THC only, 14 (26%) THCCOOH only, and 18 (34%) both cannabinoids. Detection rates were significantly different ( p < 0.05, Fishers’ exact test) between daily cannabis users (85%) and non-daily users (52%). There was no difference in detection rates between African-American and Caucasian subjects ( p > 0.3, Fisher's exact test). For specimens with detectable cannabinoids, concentrations ranged from 3.4 to >100 pg THC/mg and 0.10 to 7.3 pg THCCOOH/mg hair. THC and THCCOOH concentrations were positively correlated ( r = 0.38, p < 0.01, Pearson's product moment correlation). Using an immunoassay cutoff concentration of 5 pg THC equiv./mg hair, 83% of specimens that screened positive were confirmed by GCMSMS at a cutoff concentration of 0.1 pg THCCOOH/mg hair.