You are here:

Cannabis Edibles

posted 01/02/2017

publication DOI: 10.1373/clinchem.2016.265371 Published February 2017

Blood and Oral Fluid Cannabinoid Pharmacokinetics and Evaluation of Oral Fluid Screening Devices for Predicting Δ9-Tetrahydrocannabinol in Blood and Oral Fluid following Cannabis Brownie Administration

Matthew N. Newmeyer, Madeleine J. Swortwood, Maria Andersson, Osama A. Abulseoud, Karl B. Scheidweiler, Marilyn A. Huestis


Background: Roadside oral fluid (OF) Δ9-tetrahydro-cannabinol (THC) detection indicates recent cannabis intake. OF and blood THC pharmacokinetic data are limited and there are no on-site OF screening performance evaluations after controlled edible cannabis.

Content: We reviewed OF and blood cannabinoid pharmacokinetics and performance evaluations of the Draeger DrugTest®5000 (DT5000) and Alere™ DDS®2 (DDS2) on-site OF screening devices. We also present data from a controlled oral cannabis administration session.

Summary: OF THC maximum concentrations (Cmax) were similar in frequent as compared to occasional smokers, while blood THC Cmax were higher in frequent [mean (range) 17.7 (8.0–36.1) μg/L] smokers compared to occasional [8.2 (3.2–14.3) μg/L] smokers. Minor cannabinoids Δ9-tetrahydrocannabivarin and cannabigerol were never detected in blood, and not in OF by 5 or 8 h, respectively, with 0.3 μg/L cutoffs. Recommended performance (analytical sensitivity, specificity, and efficiency) criteria for screening devices of ≥80% are difficult to meet when maximizing true positive (TP) results with confirmation cutoffs below the screening cutoff. TPs were greatest with OF confirmation cutoffs of THC ≥1 and ≥2 μg/L, but analytical sensitivities were <80% due to false negative tests arising from confirmation cutoffs below the DT5000 and DDS2 screening cutoffs; all criteria were >80% with an OF THC ≥5 μg/L cutoff. Performance criteria also were >80% with a blood THC ≥5 μg/L confirmation cutoff; however, positive OF screening results might not confirm due to the time required to collect blood after a crash or police stop. OF confirmation is recommended for roadside OF screening.

Received for publication August 12, 2016.
Accepted for publication November 21, 2016.

© 2016 American Association for Clinical Chemistry

get involved

If you are interested in what we do and would like to support our work, find out more ways to get involved.


get our book

Drugs: It’s just not worth it

Drugs: It’s just not worth it

Our 35-page book gives clear and easy to read facts and advice aimed at teenagers and young people.


Buy Now