Evaluating the Impact of Hemp Food Consumption on Workplace Drug Tests

Authors: Leson G.¹; Pless P.¹; Grotenhermen F.²; Kalant H.³; ElSohly M.A.⁴

Source: Journal of Analytical Toxicology, Volume 25, Number 8, November/December 2001 , pp. 691-698(8)

Publisher: Preston Publications

Abstract:

Foods containing seeds or oil of the hemp plant (Cannabis sativa L.) are increasingly found in retail stores in the U.S. The presence of ⁹-tetrahydrocannabinol (THC) in these foods has raised concern over their impact on the results of workplace drug tests for marijuana. Previous studies have shown that eating hemp foods can cause screening and confirmed positive results in urine specimens. This study evaluated the impact of extended daily ingestion of THC via hemp oil on urine levels of its metabolite 11-nor-9-carboxy-⁹-tetrahydrocannabinol (THC-COOH) for four distinct daily THC doses. Doses were representative of THC levels now commonly found in hemp seed products and a range of conceivable daily consumption rates. Fifteen THC-naïve adults ingested, over four successive 10-day periods, single daily THC doses ranging from 0.09 to 0.6 mg. Subjects self-administered THC in 15-mL aliquots (20 mL for the 0.6-mg dose) of four different blends of hemp and canola oils. Urine specimens were collected prior to the first ingestion of oil, on days 9 and 10 of each of the four study periods, and 1 and 3 days after the last ingestion. All specimens were screened for cannabinoids by radioimmunoassay (Immunalysis Direct RIA Kit), confirmed for THC-COOH by gas chromatography–mass spectrometry (GC–MS), and analyzed for creatinine to identify dilute specimens. None of the subjects who ingested daily doses of 0.45 mg of THC screened positive at the 50-ng/mL cutoff. At a daily THC dose of 0.6 mg, one specimen screened positive. The highest THC-COOH level found by GC–MS in any of the specimens was 5.2 ng/mL, well below the 15-ng/mL confirmation cutoff used in federal drug testing programs. A THC intake of 0.6 mg/day is equivalent to the consumption of approximately 125 mL of hemp oil containing 5 g/g of THC or 300 g of hulled seeds at 2 g/g. These THC concentrations are now typical in Canadian hemp seed products. Based on our findings, these concentrations appear to be sufficiently low to prevent confirmed positives from the extended and extensive consumption of hemp foods.

Language: English

Document Type:

Affiliations: 1: Leson Environmental Consulting, P.O. Box 10075, Berkeley, California 94709 2: Nova Institute, Goldenbergstrae 2, 50354 Hürth, Germany e 2, 50354 Hürth, Germany "> 3: ARF Division of Centre for Addiction and Mental Health and Department of Pharmacology, University of Toronto, Toronto, Ontario, M5S 1A8, Canada 4: ElSohly Laboratories, Inc., 5 Industrial Park Drive, Oxford, Mississippi 38655

Publication date: 2001-11-01

• The Journal of Analytical Toxicology (JAT), established in 1977 and published 9 times a year, is the international source covering a broad range of clinical, forensic, and industrial laboratory topics regarding the isolation, identification, and quantitation of potentially toxic substances.

  With an emphasis on practical application, JAT articles provide improved and novel techniques for use in clinical, forensic, workplace, sports testing (doping), and other toxicology laboratories. Articles describe newly developed methods in immunoassay testing, gas chromatography, liquid chromatography, mass spectrometry, atomic absorption spectrometry, solid and liquid phase extraction techniques, and other analytical approaches. Worldwide readership includes toxicologists, pathologists, chemists, clinicians, researchers, and educators working in medical examiner and law enforcement laboratories, hospitals, university and independent analytical laboratories, as well as the drug manufacturing industry.

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