This research report describes factors that may impact the test results of specimens collected for cannabinoid drug screening.
There has been a surge in the presence and use of cannabinoids since the federal legalization of hemp in 2018. This increase is attributed not only to the use of ∆9-tetrahydrocannabinol (∆9-THC) and cannabidiol, the most abundant phytocannabinoid components of cannabis and hemp, respectively, but also to the use of many other emerging THC analogs. Structurally, these analogs are similar to ∆9-THC. Urine specimens for drug analysis are often collected offsite and transported to a laboratory for analysis. Screening assays are usually the first step in urine drug testing. These assays are usually qualitative and automated, which for negative specimens, reduces cost and reporting time. The stability of ∆9-THC and its metabolites has been known for some time; however, the stability of emerging analogs has not been elucidated, and therefore, assuming equivalent storage stability can be erroneous. Previous work assessed the cross-reactivity of ∆8-THC and its major metabolites, the ∆10-THC chiral analogs and the chiral 11-COOH-hexahydrocannabinol analogs. In this paper, the authors describe their assessment of stability for each analyte, their preparation of samples in drug-free urine at three different pHs and stored at three different temperatures, and analysis utilizing the Lin-Zhi International Cannabinoids Enzyme Immunoassay cannabinoid screening kit calibrated at the 25 ng/mL cut-off. Overall, the cannabinoid analogs produced diminishing instrument responses depending on pH and temperature. They conclude that time, storage temperature, and pH of urine specimens may affect the screening results of specimens collected for cannabinoid drug screening. Publisher Abstract Provided
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