In 2018, Canada introduced roadside oral fluid (OF) screening devices, called Approved Drug Screening Equipment (ADSE), as an investigative tool in impaired driving investigations to detect tetrahydrocannabinol (THC), cocaine and/or methamphetamine in drivers. In this work, we compare the detection and concentration of THC in blood samples collected from suspected impaired drivers that tested positive at the roadside for THC on an ADSE. The two ADSEs that were utilized were the Dräger DrugTest® 5000 (DDT) and the Abbott SoToxa™ (SoToxa) both configured with a THC OF concentration cut-off concentration of 25 ng/mL. Blood samples were screened for cannabinoids using immunoassay and positive results were followed up by confirmation/quantitation of THC by ultra-performance liquid chromatography with tandem mass spectrometry (UPLC-MS/MS). A total of 230 cases were available where a blood sample was collected from a suspected impaired driver subsequent to a positive THC screen result on an ADSE. The blood samples were taken an average of 1.4 hours (range= 9 minutes to 3.2 hours) after the ADSE test. THC was confirmed in 98% of blood samples with concentrations across all samples ranging from not detected (cut off 0.5 ng/mL) to greater than 20 ng/mL. Further, 90% of the blood samples had a THC concentration of 2.0 ng/mL (the lower per se limit in Canada) or greater. A positive ADSE test of a suspected impaired driver may predict that the driver has a detectable level of THC in their blood, and there is a high likelihood that the THC blood concentration is 2.0 ng/mL or higher. Hence, ADSE may be a useful tool for law enforcement and aid in the development of grounds to believe that a driver is operating a conveyance with a THC concentration exceeding Canadian per se limits.

中文翻译：

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加拿大批准的药物筛选设备四氢大麻酚 (THC) 临界水平的评估

2018 年，加拿大推出了路边口腔液体 (OF) 筛查设备，称为批准药物筛查设备 (ADSE)，作为驾驶不清醒调查的调查工具，以检测驾驶员中的四氢大麻酚 (THC)、可卡因和/或甲基苯丙胺。在这项工作中，我们比较了从疑似受损驾驶员收集的血液样本中 THC 的检测和浓度，这些驾驶员在路边 ADSE 上 THC 检测呈阳性。使用的两种 ADSE 是 Dräger DrugTest® 5000 (DDT) 和 Abbott SoToxa™ (SoToxa)，两者的 THC OF 浓度截止浓度均为 25 ng/mL。使用免疫测定法筛选血液样本中的大麻素，并通过超高效液相色谱串联质谱法 (UPLC-MS/MS) 确认/定量 THC，对阳性结果进行跟踪。总共有 230 个案例，在 ADSE 上 THC 筛查结果呈阳性后，从疑似受损驾驶员身上采集了血样。 ADSE 测试后平均 1.4 小时（范围 = 9 分钟至 3.2 小时）采集血样。 98% 的血液样本中均证实含有 THC，所有样本的浓度范围从未检测到（截止值 0.5 ng/mL）到大于 20 ng/mL。此外，90% 的血液样本的 THC 浓度为 2.0 ng/mL（加拿大本身的下限）或更高。疑似受损驾驶员的 ADSE 测试呈阳性，可以预测该驾驶员的血液中可检测到 THC 水平，并且 THC 血液浓度很可能为 2.0 ng/mL 或更高。因此，ADSE 可能是执法的有用工具，并有助于建立理由相信司机所驾驶的交通工具的 THC 浓度超过了加拿大本身的限制。