Veterinarians diagnose marijuana toxicity based on clinical signs and history, or in conjunction with an over-the-counter (OTC) human urine drug screen. With the legalization of recreational marijuana use becoming more prevalent in the United States, a more accurate test to aid in the diagnosis of canine marijuana toxicity is needed. We collected urine and serum samples from 19 dogs with confirmed or suspected marijuana toxicosis from multiple veterinary hospitals and analyzed them with a novel UPLC-MS/MS method. Calibrations from 0.1 to 100 ng/mL and QC materials were prepared. Samples were extracted, purified, and eluted with solid-phase extraction. Urine samples were tested with an OTC human urine drug screen. The limit of detection (LOD) and lower limit of quantification (LLOQ) ranges for marijuana metabolites in serum were 0.05–0.25 ng/mL and 0.1–0.5 ng/mL, respectively. In urine, the LOD and LLOQ ranges for the metabolites were 0.05–0.1 ng/mL and 0.1–0.5 ng/mL, respectively. In serum, median and range of metabolite concentrations (ng/mL) detected included: THC, 65.0 (0.14–160); 11-OH-Δ⁹-THC, 4.78 (1.15–17.8); 11-nor-9-carboxy-Δ⁹-THC, 2.18 (0.71–7.79); CBD, 0.28 (0.11–82.5); and THC-glucuronide, 2.05 (0.72–18.3). In the 19 urine samples, metabolite: creatinine (ng: mg) values detected included: THC, 0.22 (0.05–0.74); 11-OH-Δ⁹-THC, 0; 11-nor-9-carboxy-Δ⁹-THC, 1.32 (0.16–11.2); CBD, 0.19 (0.12–0.26); THC-COOH-glucuronide, 0.08 (0.04–0.11); and THC-glucuronide, 0.98 (0.25–10.7). Twenty of 21 urine samples tested negative for THC on the urine drug screen. All 19 serum samples contained quantifiable concentrations of THC using our novel UPLC-MS/MS method. Utilizing a UPLC-MS/MS method can be a useful aid in the diagnosis of marijuana toxicosis in dogs, whereas using an OTC human urine drug test is not a useful test for confirming marijuana exposure in dogs because of the low concentration of THC-COOH in urine.

兽医根据临床症状和病史或结合非处方 (OTC) 人尿药物筛查来诊断大麻毒性。随着休闲大麻使用合法化在美国变得越来越普遍，需要更准确的测试来帮助诊断犬类大麻的毒性。我们从多家兽医医院收集了 19 只确诊或疑似大麻中毒的狗的尿液和血清样本，并用一种​​新型的 UPLC-MS/MS 方法对其进行了分析。制备了 0.1 至 100 ng/mL 的校准物和 QC 材料。样品经萃取、纯化、固相萃取洗脱。尿液样本通过 OTC 人尿药物筛查进行了测试。血清中大麻代谢物的检测限 (LOD) 和定量下限 (LLOQ) 范围为 0.05–0。分别为 25 ng/mL 和 0.1–0.5 ng/mL。在尿液中，代谢物的 LOD 和 LLOQ 范围分别为 0.05–0.1 ng/mL 和 0.1–0.5 ng/mL。在血清中，检测到的代谢物浓度 (ng/mL) 的中位数和范围包括： THC，65.0 (0.14–160)；11-OH-Δ^{9 -}四氢大麻酚，4.78 (1.15–17.8)；11-nor-9-羧基-Δ ⁹ -THC，2.18 (0.71–7.79)；CBD，0.28（0.11-82.5）；和 THC-葡糖苷酸，2.05 (0.72–18.3)。在 19 个尿样中，检测到的代谢物：肌酐（ng：mg）值包括：THC，0.22（0.05–0.74）；11-OH-Δ ⁹ -THC，0；11-nor-9-羧基-Δ ⁹-THC，1.32 (0.16–11.2)；CBD，0.19（0.12-0.26）；THC-COOH-葡糖苷酸，0.08 (0.04–0.11)；和 THC-葡糖苷酸，0.98 (0.25–10.7)。21 份尿液样本中有 20 份在尿液药物筛查中检测为 THC 阴性。使用我们的新型 UPLC-MS/MS 方法，所有 19 个血清样品都含有可量化的 THC 浓度。使用 UPLC-MS/MS 方法可以帮助诊断狗的大麻中毒，而使用 OTC 人尿药物测试不是确认狗的大麻暴露的有用测试，因为 THC-COOH 浓度低在尿液中。