title: Cannabinoid concentrations in hair from documented cannabis users.
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 delta9-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.
authors.affiliation: Chemistry and Drug Metabolism, Intramural Research Program, National Institute on Drug Abuse, National Institutes of Health, Baltimore, MD 21224, United States. mhuestis@irp.nida.nih.gov
authors.forename: Marilyn A
authors.initials: MA
authors.lastname: Huestis
authors.forename: Richard A
authors.initials: RA
authors.lastname: Gustafson
authors.forename: Eric T
authors.initials: ET
authors.lastname: Moolchan
authors.forename: Allan
authors.initials: A
authors.lastname: Barnes
authors.forename: James A
authors.initials: JA
authors.lastname: Bourland
authors.forename: Stacy A
authors.initials: SA
authors.lastname: Sweeney
authors.forename: Eugene F
authors.initials: EF
authors.lastname: Hayes
authors.forename: Patrick M
authors.initials: PM
authors.lastname: Carpenter
authors.forename: Michael L
authors.initials: ML
authors.lastname: Smith
mesh_terms: D000328:Adult; D004311:Double-Blind Method; D013759:Dronabinol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000032:analysis*; D004797:Enzyme-Linked Immunosorbent Assay; D053593:Forensic Toxicology; D008401:Gas Chromatography-Mass Spectrometry; D006197:Hair / Q000737:chemistry*; D006213:Hallucinogens / Q000008:administration & dosage / Q000032:analysis*; D006801:Humans; D008297:Male; D002189:Marijuana Abuse; D008385:Marijuana Smoking; D015813:Substance Abuse Detection
chemical_list: D006213:Hallucinogens; C016780:11-nor-delta(9)-tetrahydrocannabinol-9-carboxylic acid; D013759:Dronabinol