publication DOI: 10.1373/clinchem.2016.265371 Published February 2017
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