MSACL 2018 US Abstract

Topic: Cannabinoids

Cannabinoids in Oral Fluid: Roadside Screening & Markers of Recent Use

Madeleine Swortwood (Presenter)
Sam Houston State University

Bio: Dr. Madeleine Swortwood graduated with a BA in Biochemistry from Duquesne University and a PhD in Chemistry from Florida International University. She completed her post-doctoral fellowship at the National Institute on Drug Abuse, where she took on a variety of research projects including a controlled drug administration clinical study, method development and validation for complex matrices, metabolic profiling of synthetic cathinones, and examining in utero drug exposure. Currently, she is a tenure-tracked Assistant Professor at Sam Houston State University in the department of Forensic Science. She oversees Masters and Doctoral level research focused on examining novel psychoactive substances in alternative matrices by use of liquid chromatography tandem mass spectrometry. She has published over 19 articles and presents her research annually at national and international conferences.

Authorship: Madeleine J. Swortwood (1), Marilyn A. Huestis (2)
(1) Sam Houston State University, Huntsville, TX; (2) University of Maryland School of Medicine, Baltimore, MD

Short Abstract

Oral fluid (OF) is an important alternative matrix for monitoring drug use. Cannabis remains the most commonly used illicit drug worldwide. Oral fluid is easily collected under direct observation, deterring adulteration, and does not require specialized personnel for collection. High concentrations of tetrahydrocannabinol (THC) result primarily from oral mucosa contamination from smoking or vaporizing cannabis and can persist. Concentrations of carboxy-THC vary considerably between frequent and occasional smokers. This presentation will examine and compare two roadside screening devices to detect recent cannabis use in oral fluid in frequent and occasional cannabis smokers following controlled smoked, vaporized, and oral cannabis administration. Additionally, presence of minor cannabinoids present in oral fluid will be discussed as potential markers of recent cannabis intake.

Long Abstract


Oral fluid (OF) is an important matrix for monitoring driving under the influence of drugs (DUID). Although smoking is the most common cannabis administration route, vaporization and oral consumption via edibles are becoming more popular. While cannabinoid disposition in oral fluid is well characterized after smoking and vaporization, few data exist after edible cannabis. Additionally, roadside OF screening devices capable of detecting tetrahydrocannabinol (THC) need to be evaluated following cannabis administration via oral route. We sought to screen OF from frequent and occasional cannabis smokers following controlled smoked, vaporized, and oral cannabis administration using commercially available roadside devices in order to evaluate device performance and correlate with confirmatory testing. Further, we sought to examine OF for presence of minor cannabinoids in order to identify recent cannabis use markers.


Frequent and occasional cannabis smokers were recruited for study participation and provided written informed consent. Over 4 randomized, double-blind dosing sessions, participants were administered 1) placebo cannabis or active cannabis (54 mg THC) via 2) cigarette, 3) vaporizer, or 4) brownie. OF was collected with Quantisal collection devices before and up to 72 h after dosing. THC, 11-hydroxy-THC, carboxy-THC, tetrahydrocannabivarin (THCV), cannabidiol (CBD), and cannabigerol (CBG) were quantified in oral fluid by a validated liquid chromatography-tandem mass spectrometry method with 0.2 ug/L limits of quantification (except 15 ng/L for carboxy-THC). Maximum concentration, time to maximum concentration, and time of last detection were determined. Following Quantisal collection, OF was also collected with either Draeger DrugTest 5000 or Alere DDS2 with 5 and 25 ug/L THC cutoffs, respectively. Sensitivity, specificity, and efficiency of devices was calculated by comparison of screening results (pos/neg) to confirmatory THC concentrations at various cutoffs.


Overall, 654 Draeger and 679 Alere results were paired with Quantisal confirmation results. Specificity and efficiency met or exceeded optimal performance criteria (>80%) for frequent and occasional smokers for both screening devices after all three cannabis routes when using 5 or 10 ug/L THC confirmatory cutoffs. Positive screening results utilizing a 5 ug/L confirmatory cutoff after smoked, vaporized, and oral cannabis were observed in Draeger samples up to 20, 12, and 20 h, respectively and in Alere samples up to 20, 10, and 5 h. In the confirmatory samples, THC maximum concentrations were significantly higher in frequent smokers after inhaled routes compared to oral administration. Minor cannabinoids, THCV, CBD, and CBG, were detected significantly later in frequent smokers after inhaled cannabis compared to oral cannabis administration. 11-hydroxy-THC was detected infrequently and never beyond 1.5 h. Carboxy-THC concentrations were varied. Presence and concentrations of minor cannabinoids resulted in detection windows indicative of recent cannabis intake for all three administration routes, regardless of smoking history.

Conclusions & Discussion

For the first time, cannabinoids and metabolites were fully characterized in OF following controlled cannabis brownie consumption with direct comparison to smoked and vaporized administration in frequent and occasional cannabis smokers. Persistance of THC and variability of carboxy-THC in OF make current data interpretation difficult. However, presence of minor cannabinoids can be indicative of recent cannabis use, regardless of administration route or smoking frequency. Evaluation of roadside screening devices indicates optimal device performance of >80% sensitivity, specificity, and efficiency for both Draeger and Alere after smoked, vaporized, and oral cannabis administration when confirming THC >5 ug/L.

References & Acknowledgements:

Oral fluid screening devices and confirmatory collection devices were provided by the manufacturers via Material Transfer Agreements between Draeger, Alere, and Immunalysis with NIH. The companies had no role in study design or data analysis.

Financial Disclosure

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