Cannabinoid concentrations in blood and urine after smoking cannabidiol joints

Forensic Sci Int. 2018 Oct:291:62-67. doi: 10.1016/j.forsciint.2018.08.009. Epub 2018 Aug 11.


In Switzerland, the sale of cannabis with tetrahydrocannabinol (THC) content less than 1% has recently been legalized. As a consequence, cannabis with low THC and high cannabidiol (CBD) values up to approximately 25% is legally available on the market. In this study, we investigated cannabinoid blood and urine concentrations of a naive user and of a modeled chronic user after smoking a single CBD joint. Chronic use was modeled as smoking 2 joints per day for 10 days. Joints contained 200mg of cannabis with THC concentrations of 0.94% and 0.8% and CBD concentrations of 23.5% and 17% in the naive-smoker and chronic-smoker experiment, respectively. After smoking, blood and urine samples were collected for 4 and 20h after smoking start, respectively. THC blood concentrations reached 2.7 and 4.5ng/mL in the naive and chronic user, respectively. In both cases, the blood THC concentration is significantly above the Swiss road traffic threshold of 1.5ng/mL. Consequently, the user was legally unfit to drive directly after smoking. CBD blood concentrations of 45.7 and 82.6ng/mL were reached for the naive and chronic user, respectively. During the 10-day smoking period, blood and urine samples were regularly collected. No accumulation of any cannabinoid was found in the blood during this time. Urinary 11-nor-9-carboxy-THC concentrations seemed to increase during the 10-day period, which is important in abstinence testing.

Keywords: Abstinence testing; Cannabidiol; Cannabinoids; Driving capacity; GC–MS/MS.

Publication types

  • Comparative Study

MeSH terms

  • Adult
  • Cannabinoids / blood*
  • Cannabinoids / urine*
  • Driving Under the Influence
  • Female
  • Gas Chromatography-Mass Spectrometry
  • Humans
  • Marijuana Abuse / blood
  • Marijuana Abuse / urine
  • Marijuana Smoking / blood*
  • Marijuana Smoking / urine*
  • Switzerland


  • Cannabinoids