Detecting and quantifying marijuana metabolites in serum and urine of 19 dogs affected by marijuana toxicity.
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-MSMS method. Calibrations from 0.1 to 100 ngmL 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 ngmL and 0.1-0.5 ngmL, respectively. In urine, the LOD and LLOQ ranges for the metabolites were 0.05-0.1 ngmL and 0.1-0.5 ngmL, respectively. In serum, median and range of metabolite concentrations (ngmL) detected included THC, 65.0 (0.14-160) 11-OH-Δ