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A blind quality control (BQC) program in blood alcohol analysis was implemented at the Houston Forensic Science Center (HFSC) in September 2015. By mimicking authentic toxicology blood evidence, the laboratory can perform a concurrent evaluation of their technical and administrative casework procedures and test the accuracy and reliability of their volatile analysis method in a format that is blinded to the analyst. From September 2015 to November 2023, HFSC's Quality Division submitted 1228 antemortem whole blood samples: 292 ethanol-negative samples and 936 ethanol-positive samples at sixteen target concentrations (0.051, 0.080, 0.100, 0.110, 0.120, 0.130, 0.150, 0.160, 0.170, 0.180, 0.190, 0.200, 0.230, 0.240, 0.250, and 0.260 g/dL). A second, unopened blood tube in 168 of the 1228 BQCs was also analyzed after 721-1140 days: 24 ethanol-negative samples and 144 ethanol-positive samples at five target concentrations (0.080, 0.100, 0.130, 0.180, and 0.240 g/dL). All 316 ethanol-negative samples remained negative. After 42-758 days, the average (median, range) change in ethanol concentration of the 936 positive samples was -1.4% (-1.3%, -12.0% to +8.4%) with a statistically significant difference (P < 0.001) observed for the gradual decline in blood alcohol concentration (BAC) over time. The average BAC percentage differences per target concentration, ranged from -6.4% (-0.008 g/dL) to +5.7% (+0.011 g/dL), were within HFSC's current measurement uncertainty (9.4% at k=3), showing no apparent correlation between the change in ethanol and the theoretical target concentration. As the analysis time between the two blood specimens from the same evidence kit extended, the loss in ethanol significantly increased (P < 0.001)., (© The Author(s) 2024. Published by Oxford University Press. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site–for further information please contact journals.permissions@oup.com.)

In recent years, the emergence of the novel designer benzodiazepine 4'-chloro deschloroalprazolam has presented a new challenge for forensic laboratories by interfering with the identification and quantitation of alprazolam. As an isomer of alprazolam, 4'-chloro deschloroalprazolam has similar physicochemical properties and can be misidentified in casework samples as alprazolam without a specific method to differentiate the two analytes. Starting in late 2021, the Houston Forensic Science Center (HFSC) received toxicological and seized drug evidence indicating the presence of 4'-chloro deschloroalprazolam. An interference study was performed to supplement the laboratory's validated benzodiazepines method for toxicological samples to differentiate alprazolam from 4'-chloro deschloroalprazolam. This study showed that while the isomers could not be chromatographically resolved using the current method, they could be differentiated based on their retention times relative to the internal standard, alprazolam-d5. Based on these findings, the HFSC toxicology laboratory reports test results as "unsuitable for analysis due to an interference" if a suspected alprazolam peak elutes before the alprazolam-d5 peak, even if all identification and quantification criteria (e.g., retention time) were acceptable. Additionally, the seized drug and toxicology laboratories re-evaluated previously analyzed alprazolam-positive casework to determine if suspected 4'-chloro deschloroalprazolam had been misidentified as alprazolam. This report presents three cases: one case with toxicological evidence indicating the presence of both 4'-chloro deschloroalprazolam and alprazolam, and two cases with both seized drug material and toxicology evidence indicating the presence of 4'chloro deschloroalprazolam with no detected alprazolam., (© The Author(s) 2023. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Drug-impaired driving is a growing public safety issue. Addressing impairment due to drugs other than ethanol can be challenging for forensic toxicologists as many factors need to be considered including the type of drug(s), drug-drug interaction, the dose(s) and the individual's physiological condition and drug use history. Interpretation of blood drug test results is additionally difficult as drug concentrations in impaired driving cases may overlap levels typically viewed as toxic. This study compares blood concentrations of drugs in impaired driving cases to those in postmortem cases in Houston, TX, from 2014 to 2020. Blood drug concentrations from driving while intoxicated (DWI) or driving under the influence of drugs (DUID) cases submitted to Houston Forensic Science Center (HFSC) and Harris County Institute of Forensic Sciences (HCIFS) were compared to postmortem blood test results from HCIFS. Eight DWI/DUID cases had drugs that exceeded impaired driving concentrations reported in the literature. These drugs included fentanyl (220 ng/mL), oxycodone (680 ng/mL), hydrocodone (310 and 490 ng/mL), clonazepam (330 ng/mL), methamphetamine (3,500 and 7,100 ng/mL) and tetrahydrocannabinol (THC) (160 ng/mL). For oxycodone and hydrocodone, the presented DWI/DUID cases exceeded 91% and 96% of postmortem concentrations, respectively. The 7,100 ng/mL methamphetamine DWI/DUID result was greater than 98% of postmortem cases. The presented DWI/DUID concentrations were higher than all but one postmortem case for clonazepam and higher than all postmortem cases for THC. This study demonstrates that extremely high drug concentrations in DWI/DUID casework blur the line between therapeutic/recreational and toxic concentrations., (© The Author(s) 2022. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Driving while intoxicated (DWI) or driving under the influence of drugs (DUID) poses a continued public safety risk in Texas, which has one of the highest alcohol impaired traffic fatality rates. This study aimed to identify alcohol and drug use trends seen in DWI/DUID cases in the city of Houston from 2014 to 2018 to better understand the populations at risk. Blood samples submitted to the Houston Forensic Science Center (HFSC) were evaluated for blood alcohol concentration (BAC), drug concentrations and demographics. During the 5-year period, 12,682 Houston driver blood samples had a mean (median) BAC of 0.151 g/dL (0.167 g/dL) and age of 36.3 (34) years. Fifty percent of samples were white males. Seventy-five percent of samples were individuals aged 21 to 44 years. Between 2014 and 2018, the number of cases submitted nearly doubled, from approximately 2,000 cases per year to over 3,700. In 2014, 23% of cases submitted required further analysis per HFSC testing policy (drug screen and confirmation for DWI/DUID cases when BAC < 0.100 g/dL), which rose to 27% by 2018. Of those, 36% were polydrug cases, requiring two or more confirmation tests. Cannabinoids was the most common drug class detected (34% of cases analyzed for drugs), followed by benzodiazepines (25%), phencyclidine (20%), cocaine/metabolites (15%) and opioids (12%). Phencyclidine rose from the fifth-most commonly detected drug in 2014 to the second-most drug in 2018. Only 3% of all cases (n = 408) were negative for both alcohol and drugs. Communication between law enforcement and laboratory management is recommended to address growing caseload more effectively. The study limitations (e.g., limited scope of analysis) suggest the present data underestimated the full extent of impaired driving in Houston, indicating even more urgent needs for increasing resources and efforts to reduce this serious threat to public safety., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Phencyclidine (PCP) was first synthesized in 1926 and originally developed in 1950s as a general anesthetic agent. Abuse of PCP declined at the national level since its first illicit use in 1960s, but it continues in certain areas including Houston. This research evaluates PCP-positive cases of driving while intoxicated (DWI) in 2013-2018. The blood samples were collected from drivers, submitted by the Houston Police Department and analyzed for alcohol and drugs. Toxicological findings and demographic information were evaluated for the impaired driving cases tested positive for PCP in blood. Additionally, the Drug Recognition Expert (DRE) findings were examined for 12 cases in 2018. A total of 615 DWI cases positive for PCP in blood were identified in which the traffic offense occurred between August 2013 and December 2018. The mean (median, range) PCP concentration was 47 (43, 7-180) ng/mL. A total of 23% of those cases were females, and 77% were males; 85% were blacks, 10% were whites and 5% were other races/ethnicities as identified by the arresting officer. The mean age was 37 years. No significant differences in median and distribution of PCP concentrations (P's > 0.05) were observed across the offense years and among demographic cohorts. A total of 43% of the cases were positive for PCP only. Among the remaining 57%, cannabinoids are the most common concurrently detected analytes (35%), followed by cocaine/metabolite (14%) and ethanol (13%). The proportion of black male PCP-positive drivers decreased in younger age groups. Common indications observed by DRE officers included slurred speech, chemical breath odor, watery and/or bloodshot eyes, vertical/horizontal gaze nystagmus and impaired coordination/balance. This study provides valuable regional information to better understand the demographic patterns of PCP-impaired drivers in Houston, TX over 6 years. The findings may aid in designing and implementing regulations and prevention programs to reduce PCP-impaired driving., (© The Author(s) 2020. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)

Declared proficiency tests are limited in their use for testing the performance of the entire system, because analysts are aware that they are being tested. A blind quality control (BQC) is intended to appear as a real case to the analyst to remove any intentional or subconscious bias. A BQC program allows a real-time assessment of the laboratory's policies and procedures and monitors reliability of casework. In September 2015, the Houston Forensic Science Center (HFSC) began a BQC program in blood alcohol analysis. Between September 2015 and July 2018, HFSC submitted 317 blind cases: 89 negative samples and 228 positive samples at five target concentrations (0.08, 0.15, 0.16, 0.20 and 0.25 g/100 mL; theoretical targets). These blood samples were analyzed by a headspace gas chromatograph interfaced with dual-flame ionization detectors (HS-GC-FID). All negative samples produced `no ethanol detected' results. The mean (range) of reported blood alcohol concentrations (BACs) for the aforementioned target concentrations was 0.075 (0.073-0.078), 0.144 (0.140-0.148), 0.157 (0.155-0.160), 0.195 (0.192-0.200) and 0.249 (0.242-0.258) g/100 mL, respectively. The average BAC percent differences from the target for the positive blind cases ranged from -0.4 to -6.3%, within our uncertainty of measurement (8.95-9.18%). The rate of alcohol evaporation/degradation was determined negligible. A multiple linear regression analysis was performed to compare the % difference in BAC among five target concentrations, eight analysts, three HS-GC-FID instruments and two pipettes. The variables other than target concentrations showed no significant difference (P > 0.2). While the 0.08 g/100 mL target showed a significantly larger % difference than higher target concentrations (0.15-0.25 g/100 mL), the % differences among the higher targets were not concentration-dependent. Despite difficulties like gaining buy-in from stakeholders and mimicking evidence samples, the implementation of a BQC program has improved processes, shown methods are reliable and added confidence to staff's testimony in court., (© The Author(s) 2019. Published by Oxford University Press. All rights reserved. For permissions, please email: journals.permissions@oup.com.)