Blood drug analysis and substance use profile in cases suspected of driving under the influence of drugs in Kayseri, Turkiye

Background & Aims: There is extensive research in the literature that substance use increases traffic accidents byimpairing the visual, cognitive and/or motor abilities necessary for safe driving. This poses a threat to public safetyfor other drivers and pedestrians. In cases of driving under the influence of drugs, blood substance analysis is extremely valuable because it showsbeing "under the influence of drugs" and is closed to adulteration. Therefore, it has important evidentiary value inforensic toxicology.In this study, we aimed to investigate the rates of substance positivity and the most detected substances in bloodsamples admitted to our laboratory with suspicion of driving under the influence of drug within the past year, andto reveal the current status of substance abuse in our city.Methods: Between March 1, 2023 and February 15, 2024, blood samples (n=327) admitted to Erciyes UniversityDrug Application and Research Center Medical Biochemistry Laboratory by law enforcements for drug screeningand confirmation analyses were included in the study. Following liquid-liquid extraction, precipitation and evaporation pretreatments, the blood samples were analyzed using a validated method on a SCIEX Triple Quad 5500+QTRAP liquid chromatography-mass spectrometer (LC-MS/MS). A total of 90 substances were screened and thetotal run time was 10 minutes. Results were quantified by analyte/IS areas on Sciex OS® software and spectral validation was performed using the mzCloud Mass Spectral Library. For positive samples, demographic data, detectedsubstances and their blood levels were reviewedResults & Discussion: During the specified period, a total of 327 blood samples were admitted to the laboratoryfor substance analysis, belonging to individuals aged between 12 and 77 years (mean age 32.8 years), including 24(7.3%) females and 303 (92.7%) males. Of these, 79% (n=259) tested positive for at least one substance above thelimit of quantification (LOQ), with single substance abuse detected in 62% (n=204) and multiple substance detected in 17% (n=55). Indeed, 21% (n=68) tested negative. The mean age of the positive group was 32.6 years (range 16-58) and the mean age of the negative group was 33.5years (range 12-77) (p=0.473). While 95.4% (n=247) of the positive group was male, 82.4% (n=56) of the negativegroup was male (p=0.001).Methamphetamine and amphetamines were the predominant substance group detected in blood (86.1%), followedby cannabis (13.9%), while cocaine was the least frequently detected substance (1.2%). Additionally, 13.9% (n=36)of samples tested positive for substances beyond the standard five-panel screen (amphetamines, opiates, cannabis, cocaine, and benzodiazepines), with pregabalin (52.8%) and gabapentin (36.1%) being the most frequentlydetected substances within this category.According to the cut-off values determined in the "Driving under the Influence of Drugs, Alcohol, and Medicines(DRIUD)" project, the rate of positive samples above the cut-off value were considered as individuals under substance influence and the rate was 88.8% (n=198) for the amphetamine group, 61.1% (n=22) for the cannabis group,44.4% (n=4) for the benzodiazepine group, 16.6% (n=3) for the opioid group, and 66.6% (n=2) for the cocainegroup, resulting in an overall rate of 79.2% (n=229).Our study presents the results of blood drug analysis and the substance use profile of cases associated with suspicion of driving under the influence of drugs. At least one substance above the quantitation limit was detectedin 79% of suspected cases. In addition, polysubstance abuse was detected in almost one in five cases (17%). Themost commonly abused substances were amphetamines and cannabis. Furthermore, the detection of substancesbeyond the standard five-panel screen in a significant proportion of cases (13.9%) indicates that pregabalin andgabapentin use is widespread in Turkey and suggests that screening analyses should be more comprehensive toinclude these substances.Substance concentrations above the cut-off value indicating that drivers were under the influence of drugs weredetected in more than half of the cases. These findings confirm the association of substance use with driving impairment and demonstrate once again that it is a widespread problem in society.Conclusion: The present findings of our study emphasize that methamphetamine and amphetamines are the mostly abused substances for drivers and pregabalin and gabapentin are the most accompanying drugs in Kayseri city inTurkiye, which may pose a serious threat to traffic safety problem.