Samples obtained from a total of 56 dogs with either confirmed or suspected exposure to Δ9- tetrahydrocannabidiol (Δ9-THC) have been analyzed by both point of care and liquid chromatography/tandem mass spectrometry (LC/MS-MS). Of those enrolled, 55 (98%) were confirmed positive for Δ9-THC by LC/MS-MS on plasma samples. Of the 56 urine samples tested, 17 tested positive using the Alere drug screen iCassette for THC, and 26 tested positive using the NarcoCheck THC Predosage test.
All of the samples that tested positive using the Alere drug screen also had positive detection using the NarcoCheck test. Sensitivity, as calculated based on positive NarcoCheck urine drug screening, was calculated as 47%. The most commonly reported clinical signs in those positive by urine drug screening test included hyperesthesia (100%), ataxia (92%), and depressed level of mentation (80%); however, no physical examination parameter was predictive of a positive urine drug screening test in those positive for Δ9-THC on LC/MS-MS.
Work continues for validation of LC/MSMS for metabolites of Δ9-THC in canine urine samples. Results from this analysis will provide information regarding the accuracy of urine metabolites in establishing exposure to Δ9-THC in dogs.