Suitability of SoToxa oral fluid screening over time: re-examination of drugged driving in Wisconsin
Journal of Analytical Toxicology
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Drug impaired driver detection is a critical element of traffic safety. However, shifting drug use patterns over time and geography may limit long-term reliability of assay-based screening tools. In this work, we compare qualitative results from the Abbot SoToxa® oral fluid (OF) screening device to Quantisal™ OF and whole blood. Our objective was to examine these three qualitative toxicological approaches, scope applicability of OF collection at the roadside, and compare to a previous analysis of SoToxa in Wisconsin. OF specimens were screened with the SoToxa® for six drugs or drug classes including amphetamine, benzodiazepines, cocaine, methamphetamine, opioids, and tetrahydrocannabinol (THC). OF and blood specimens were collected from 106 participants. Quantisal™ OF and blood specimens were screened for drugs on ultra-performance liquid chromatography coupled to quadrupole time-of-flight high-resolution mass spectrometry (UPLC-QToF-HRMS) using a data independent acquisition mode. UPLC-QToF-HRMS data was compared to comprehensive spectral libraries and drugs were qualitatively identified. Drug Recognition Expert evaluations were performed, and face sheets submitted for 21 participants in this work. In general, the SoToxa® results were consistent with the combined qualitative results observed in Quantisal™ OF specimens and whole blood specimens. Limitations were uncovered for benzodiazepines, opioids, and THC. The SoToxa® benzodiazepine analysis appeared to be cross-reactive with alprazolam but not with clonazepam or diazepam. SoToxa® opioid screening did not detect fentanyl, which is increasingly prevalent among drug users. Finally, ∆9-THC and its major metabolite 11-nor-9-carboxy-∆9-THC are lipophilic, limiting partitioning into oral fluid. Despite these limitations, the SoToxa® instrument may be useful in assisting law enforcement with identifying individuals driving under the influence of drugs and establishing probable cause at roadside for making impaired driving arrests. Furthermore, Quantisal™ OF may be useful as screening specimens due to their ease of collection and results consistent with whole blood.