RCU Labs, Inc., 408 Sunrise Ave, Roseville, CA 95661-4123, United States.
Professor Emeritus, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States.
J AOAC Int. 2024 May 2;107(3):493-505. doi: 10.1093/jaoacint/qsae015.
While current analytical methodologies can readily identify cannabis use, definitively establishing recent use within the impairment window has proven to be far more complex, requiring a new approach. Recent studies have shown no direct relationship between impairment and Δ9-tetra-hydrocannabinol (Δ9-THC) concentrations in blood or saliva, making legal "per se" Δ9-THC limits scientifically unjustified. Current methods that focus on Δ9-THC and/or metabolite concentrations in blood, saliva, urine, or exhaled breath can lead to false-positive results for recent use due to the persistence of Δ9-THC well outside of the typical 3-4 h window of potential impairment following cannabis inhalation. There is also the issue of impairment due to other intoxicating substances-just because a subject exhibits signs of impairment and cannabis use is detected does not rule out the involvement of other drugs. Compounding the matter is the increasing popularity of hemp-derived cannabidiol (CBD) products following passage of the 2018 Farm Bill, which legalized industrial hemp in the United States. Many of these products contain varying levels of Δ9-THC, which can lead to false-positive tests for cannabis use. Furthermore, hemp-derived CBD is used to synthesize Δ8-THC, which possesses psychoactive properties similar to Δ9-THC and is surrounded by legal controversy. For accuracy, analytical methods must be able to distinguish the various THC isomers, which have identical masses and exhibit immunological cross-reactivity. A new testing approach has been developed based on exhaled breath and blood sampling that incorporates kinetic changes and the presence of key cannabinoids to detect recent cannabis use within the impairment window without the false-positive results seen with other methods. The complexity of determining recent cannabis use that may lead to impairment demands such a comprehensive method so that irresponsible users can be accurately detected without falsely accusing responsible users who may unjustly suffer harsh, life-changing consequences.
虽然当前的分析方法可以很容易地识别大麻的使用情况，但在损伤窗口内明确确定最近的使用情况却证明要复杂得多，需要一种新的方法。最近的研究表明，在血液或唾液中的损伤与 Δ9-四氢大麻酚（Δ9-THC）浓度之间没有直接关系，这使得法律上“本身”的 Δ9-THC 限制在科学上是没有道理的。目前的方法侧重于血液、唾液、尿液或呼气中 Δ9-THC 和/或代谢物的浓度，由于大麻吸入后潜在损伤的典型 3-4 小时窗口之外 Δ9-THC 的持续存在，可能导致最近使用的假阳性结果。还有由于其他致醉物质造成损伤的问题-仅仅因为受试者表现出损伤迹象并且检测到大麻使用，并不排除其他药物的参与。使问题更加复杂的是，2018 年《农场法案》通过后，源自大麻的大麻二酚（CBD）产品越来越受欢迎，该法案使美国的工业大麻合法化。这些产品中的许多都含有不同水平的 Δ9-THC，这可能导致大麻使用的假阳性测试。此外，源自大麻的 CBD 用于合成 Δ8-THC，它具有与 Δ9-THC 相似的致幻特性，并且受到法律争议的包围。为了准确性，分析方法必须能够区分各种 THC 异构体，它们具有相同的质量并表现出免疫交叉反应性。已经开发出一种新的测试方法，该方法基于呼气和血液采样，结合动力学变化和关键大麻素的存在，以在损伤窗口内检测最近的大麻使用，而不会出现其他方法中看到的假阳性结果。确定可能导致损伤的最近大麻使用的复杂性要求使用这种全面的方法，以便能够准确检测不负责任的使用者，而不会错误地指责可能遭受严厉、改变生活后果的负责任的使用者。
