Δ8-Tetrahydrocannabinol (Δ8-THC) recently became widely available as an alternative to cannabis. Δ8-THC is likely impairing and poses a threat to workplace and traffic safety. In the present study the prevalence of Δ8-THC in workplace drug testing was investigated by analyzing 1,504 urine specimens with a positive immunoassay cannabinoid initial test using an LC–MS-MS method quantifying 15 cannabinoid analytes after hydrolysis. Δ8-tetrahydrocannabinol-9-carboxylic acid (Δ8-THC-COOH) was detected in 378 urine specimens (15 ng/mL cutoff), compared to 1,144 specimens containing Δ9-THC-COOH. The data could be divided into three general groups. There were 964 (76%) Δ9-THC-COOH dominant (<10% Δ8-THC-COOH) and 139 (11%) Δ8-THC-COOH dominant (>90% Δ8-THC-COOH) specimens, with the remaining 164 (13%) specimens showing a mixture of both analytes (>90% Δ8-THC-COOH). Similar concentrations of Δ9-THC-COOH (median 187 ng/mL) and Δ8-THC-COOH (150 ng/mL) as the dominant species support the use of similar cutoffs and decision rules for both analytes. Apart from the carboxylic acid metabolites, 11-hydroxy-Δ9-tetrahydrocannabinol (11-OH-Δ9-THC, n = 1,282), Δ9-tetrahydrocannabivarin-9-carboxylic acid (Δ9-THCV-COOH, n = 1,058), Δ9-THC (n = 746) and 7-hydroxy-cannabidiol (7-OH-CBD, n = 506) were the most prevalent analytes. Two specimens (0.13%) contained ≥140 ng/mL Δ9-THC without Δ9-THC-COOH, which could be due to genetic variability in the drug metabolizing enzyme CYP2C9 or an adulterant targeting Δ9-THC-COOH. The cannabinoid immunoassay was repeated, and five specimens (0.33%) generated negative initial tests despite Δ9-THC-COOH concentrations of 54–1,000 ng/mL, potentially indicative of adulteration. The use of Δ8-THC is widespread in the US populations, and all forensic laboratories should consider adding Δ8-THC and/or Δ8-THC-COOH to their scope of testing. Similar urinary concentrations were observed for both analytes indicating that the decision rules used for Δ9-THC-COOH are appropriate also for Δ8-THC-COOH.

中文翻译：

---

工作场所药物检测中 Δ8-四氢大麻酚羧酸的流行率

Δ8-四氢大麻酚（Δ8-THC）最近作为大麻的替代品被广泛使用。Δ8-THC 可能会损害工作场所和交通安全并对其构成威胁。在本研究中，通过使用 LC-MS-MS 方法对水解后 15 种大麻素分析物进行定量，对 1,504 份大麻素免疫分析呈阳性初始测试的尿液样本进行分析，调查了 Δ8-THC 在工作场所药物检测中的流行情况。在 378 份尿液样本中检测到 Δ8-四氢大麻酚-9-羧酸 (Δ8-THC-COOH)（截止值 15 ng/mL），而 1,144 份样本含有 Δ9-THC-COOH。数据可分为三组。有 964 个 (76%) Δ9-THC-COOH 占优势 (<10% Δ8-THC-COOH) 和 139 个 (11%) Δ8-THC-COOH 占优势 (>90% Δ8-THC-COOH) 样本，其余164个(13％)样本显示两种分析物的混合物(＞90％Δ8-THC-COOH)。Δ9-THC-COOH（中位数 187 ng/mL）和 Δ8-THC-COOH（150 ng/mL）作为主要物种的浓度相似，支持对两种分析物使用相似的截止值和决策规则。除羧酸代谢物外，还有 11-羟基-Δ9-四氢大麻酚 (11-OH-Δ9-THC，n = 1,282)、Δ9-四氢大麻素-9-羧酸 (Δ9-THCV-COOH，n = 1,058)、Δ9- THC (n = 746) 和 7-羟基大麻二酚 (7-OH-CBD, n = 506) 是最常见的分析物。两个样本 (0.13%) 含有 ≥140 ng/mL Δ9-THC，不含 Δ9-THC-COOH，这可能是由于药物代谢酶 CYP2C9 的遗传变异或针对 Δ9-THC-COOH 的掺杂剂所致。重复进行大麻素免疫测定，尽管 Δ9-THC-COOH 浓度为 54–1,000 ng/mL，但 5 个样本 (0.33%) 的初始测试结果为阴性，可能表明存在掺假。Δ8-THC 在美国人群中广泛使用，所有法医实验室应考虑将 Δ8-THC 和/或 Δ8-THC-COOH 添加到其测试范围中。两种分析物观察到相似的尿浓度，表明用于 Δ9-THC-COOH 的决策规则也适用于 Δ8-THC-COOH。