National Centre on Addiction and Doping, Istituto Superiore di Sanità, Rome, Italy.
Unit of Forensic Toxicology (UoFT), Department of Anatomical, Histological, Forensic and Orthopedic Sciences, Sapienza University of Rome, Rome, Italy.
Clin Chem Lab Med. 2018 Dec 19;57(2):238-243. doi: 10.1515/cclm-2018-0566.
Background In those countries where cannabis use is still illegal, some manufacturers started producing and selling "light cannabis": dried flowering tops containing the psychoactive principle Δ-9-tetrahydrocannabinol (THC) at concentrations lower than 0.2% together with variable concentration of cannabidiol (CBD). We here report a pilot study on the determination of cannabinoids in the oral fluid and urine of six individuals after smoking 1 g of "light cannabis". Methods On site screening for oral fluid samples was performed, as a laboratory immunoassay test for urine samples. A validated gas chromatography-mass spectrometry (GC-MS) method was then applied to quantify THC and CBD, independently from results of screening tests. Results On site screening for oral fluid samples, with a THC cut-off of 25 ng/mL gave negative results for all the individuals at different times after smoking. Similarly, negative results for urine samples screening from all the individuals were obtained. Confirmation analyses showed that oral fluid THC was in the concentration range from 2.5 to 21.5 ng/mL in the first 30 min after smoking and then values slowly decreased. CBD values were usually one order of magnitude higher than those of THC. THC-COOH, the principal urinary THC metabolite, presented the maximum urinary value of 1.8 ng/mL, while urinary CBD had a value of 15.1 ng/mL. Conclusions Consumers of a single 1 g dose of "light cannabis" did not result as positive in urine screening, assessing recent consumption, so that confirmation would not be required. Conversely, they might result as positive to oral fluid testing with some on-site kits, with THC cut-off lower than 25 ng/mL, at least in the first hour after smoking and hence confirmation analysis can be then required. No conclusions can be drawn of eventual chronic users.
在一些大麻使用仍属非法的国家，一些制造商开始生产和销售“低浓度大麻”：含有低于 0.2%精神活性成分 Δ-9-四氢大麻酚（THC）的干燥开花顶部分支，以及具有可变浓度大麻二酚（CBD）。在此，我们报告了一项关于六名个体吸食 1 克“低浓度大麻”后口腔液和尿液中大麻素的初步研究。
现场筛查口腔液样本，实验室免疫检测尿液样本。然后应用经验证的气相色谱-质谱（GC-MS）方法独立于筛查试验结果来定量 THC 和 CBD。
现场筛查口腔液样本，以 25 ng/mL 的 THC 截断值，在吸烟后不同时间，所有个体均呈阴性结果。同样，对所有个体的尿液样本筛查均呈阴性结果。确认分析表明，在吸烟后 30 分钟内，口腔液中的 THC 浓度范围为 2.5 至 21.5 ng/mL，然后值缓慢下降。CBD 值通常比 THC 值高一个数量级。主要的尿液 THC 代谢物 THC-COOH，其尿液最大值为 1.8 ng/mL，而尿液 CBD 值为 15.1 ng/mL。
单次吸食 1 克“低浓度大麻”的消费者在评估近期消费时，尿液筛查结果不会呈阳性，因此无需确认。相反，他们可能会对现场检测试剂盒呈阳性，尤其是在吸烟后第一小时内，这些试剂盒的 THC 截断值低于 25 ng/mL，因此可能需要进行确认分析。对于潜在的长期使用者，无法得出结论。
