Trace Detection of Adulterants in Illicit Opioid Samples Using Surface-Enhanced Raman Scattering and Random Forest Classification.

The detection of trace adulterants in opioid samples is an important aspect of drug checking, a harm reduction measure that is required as a result of the variability and unpredictability of the illicit drug supply. While many analytical methods are suitable for such analysis, community-based approaches require techniques that are amenable to point-of-care applications with minimal sample preparation and automated analysis. We demonstrate that surface-enhanced Raman spectroscopy (SERS), combined with a random forest classifier, is able to detect the presence of two common sedatives, bromazolam (0.32-36% w/w) and xylazine (0.15-15% w/w), found in street opioid samples collected as a part of a community drug checking service. The Raman predictions, benchmarked against mass spectrometry results, exhibited high specificity (88% for bromazolam, 96% for xylazine) and sensitivity (88% for bromazolam, 92% for xylazine) for the compounds of interest. We additionally provide evidence that this exceeds the performance of a more conventional approach using infrared spectral data acquired on the same samples. This demonstrates the feasibility of SERS for point-of-care analysis of challenging multicomponent samples containing trace adulterants.

Beyond a spec: assessing heterogeneity in the unregulated opioid supply.

BACKGROUND: Drug checking services aim to provide compositional information for the illicit drug supply and are being employed in public health responses to extreme rates of overdose associated with fentanyl within street opioids. The technologies used within these services range from basic qualitative tests, such as immunoassay test strips, to comprehensive quantitative analyses, such as mass spectrometry. In general, there is concern that heterogeneity of a drug mixture adds significant uncertainty when using drug checking results based on a small subsamples. The presence of hot spots of active drug components in this context is often termed the 'chocolate chip cookie effect'. Establishing the limitations of the service are essential for interpretation of the results. METHODS: This study assesses the consequence of drug heterogeneity and sampling of consumer level opioid purchased in Victoria, British Columbia ( n = 21 , 50-100 mg each) on quantitative fentanyl results determined from testing with paper spray mass spectrometry. RESULTS: Using descriptive statistics, such as relative standard deviation and interquartile range, the results demonstrate varied distributions of fentanyl concentrations within a single drug batch. However, the presence of hot spots, defined as outliers, were relatively rare. CONCLUSIONS: This study found that the variability in fentanyl concentration from drug heterogeneity and sampling is greater than that attributed to the analytical technique. On a practical level, this provides data to help guide communication of limitations of drug checking services, supporting the aim of trust and transparency between services and people who use drugs. However, if drug checking services continue to be restricted from fully engaging with the reality of manufacturing, buying, selling, mixing and dosing practices, the accuracy, usefulness, and impact will always be limited.

Planning and implementing community-based drug checking services in Scotland: a qualitative exploration using the consolidated framework for implementation research.

BACKGROUND: Drug checking services (DCS) provide harm reduction support and advice to individuals based on chemical analysis of submitted substances of concern. Whilst there are currently no DCS in Scotland, community-based services are being planned in three cities. METHODS: In this paper, we report qualitative findings based on interviews with 43 participants, focused on perceptions of DCS and their implementation. Participants were relevant professionals, those with experience of drug use, and family members of those with experience of drug use. The Consolidated Framework for Implementation Research (CFIR) was used to inform data collection and analysis. We report findings under nine constructs/themes across the five CFIR domains. RESULTS: Participants noted the importance of DCS being implemented in low-threshold, trusted services with a harm reduction ethos, and outlined a range of further service design considerations such as speed of testing, and information provided through the analysis process. In relation to the 'inner setting', a key finding related to the potential value of leveraging existing resources in order to expand both reach and effectiveness of drug trend communication. The approach of local and national police to DCS, and the attitudes of the public and local community, were described as important external factors which could influence the success (or otherwise) of implementation. Bringing together a range of stakeholders in dialogue and developing tailored communication strategies were seen as ways to build support for DCS. Overall, we found high levels of support and perceived need for DCS amongst all stakeholder groups. CONCLUSIONS: Our findings present initial implementation considerations for Scotland which could be further explored as DCS are operationalised. Further, our focus on implementation contexts is relevant to research on DCS more generally, given the minimal consideration of such issues in the literature.

Toward automated infrared spectral analysis in community drug checking.

The body of knowledge surrounding infrared spectral analysis of drug mixtures continues to grow alongside the physical expansion of drug checking services. Technicians trained in the analysis of spectroscopic data are essential for reasons that go beyond the accuracy of the analytical results. Significant barriers faced by people who use drugs in engaging with drug checking services include the speed and accuracy of the results, and the availability and accessibility of the service. These barriers can be overcome by the automation of interpretations. A random forest model for the detection of two compounds, MDA and fluorofentanyl, was trained and optimized with drug samples acquired at a community drug checking site. This resulted in a 79% true positive and 100% true negative rate for MDA, and 61% true positive and 97% true negative rate for fluorofentanyl. The trained models were applied to selected drug samples to demonstrate a proposed workflow for interpreting and validating model predictions. The detection of MDA was demonstrated on three mixtures: (1) MDMA and MDA, (2) MDA and dimethylsulfone, and (3) fentanyl, etizolam, and benzocaine. The classification of fluorofentanyl was applied to a drug mixture containing fentanyl, fluorofentanyl, 4-anilino-N-phenethylpiperidine, caffeine, and mannitol. Feature importance was calculated using shapely additive explanations to better explain the model predictions and k-nearest neighbors was used for visual comparison to labelled training data. This is a step toward building appropriate trust in computer-assisted interpretations in order to promote their use in a harm reduction context.

Teledentistry content in Canadian dental and dental hygiene curricula.

OBJECTIVES: To explore the extent to which teledentistry (TD) content is incorporated into Canadian dental and dental hygiene curricula. METHODS: An anonymous survey was distributed among all 10 dental and 35 dental hygiene programs across Canada in June and July 2022. The survey focused on TD teaching (methods employed, content taught, and barriers to TD education), with descriptive (frequency, maximum, minimum, mean) and inferential (Pearson chi-square for odds ratio test) data analyses using SPSS. A ρ - value < 0.05 was considered statistically significant. RESULTS: Thirty-four programs responsed to the survey, including all dental (n = 10) and 68% (n = 24) of dental hygiene programs; eighteen reported having TD content, including three dental programs. An average of 9.22 ± 4.86 h was reported for teaching TD, with lecture format as the most employed approach and using TD in dental practice as the most covered topic. While 53% of the dental hygiene programs employed formative and summative assessments, only one dental program reported having assessment for this content. Moreover, programs that dedicated less than 9 h to teaching this content were less likely to address more than seven topics (Odds ratio (OR) = 0.14). CONCLUSION: The dental and dental hygiene programs in Canada differ in their offering TD education, and 30% of the dental and 62.5% of the surveyed dental hygiene programs addressed TD content. This scarcity emphasizes the necessity for incorporating such content in future curriculum planning to consequently decrease the lack of knowledge, an identified barrier to TD implementation in education and practice, as today's students will be future educators.

"It would really support the wider harm reduction agenda across the board": A qualitative study of the potential impacts of drug checking service delivery in Scotland.

Drug checking services (DCS) enable individuals to voluntarily submit a small amount of a substance for analysis, providing information about the content of the substance along with tailored harm reduction support and advice. There is some evidence suggesting that DCS may lead to behaviour and system change, with impacts for people who use drugs, staff and services, and public health structures. The evidence base is still relatively nascent, however, and several evidence gaps persist. This paper reports on qualitative interviews with forty-three participants across three Scottish cities where the implementation of community-based DCS is being planned. Participants were drawn from three groups: professional participants; people with experience of drug use; and affected family members. Findings focus on perceived harm reduction impacts of DCS delivery in Scotland, with participants highlighting the potential for drug checking to impact a number of key groups including: individual service users; harm reduction services and staff; drug market monitoring structures and networks; and wider groups of people who use and sell drugs, in shaping their interactions with the drug market. Whilst continued evaluation of individual health behaviour outcomes is crucial to building the evidence base for DCS, the findings highlight the importance of extending evaluation beyond these outcomes. This would include evaluation of processes such as: information sharing across a range of parties; engagement with harm reduction and treatment services; knowledge building; and increased drug literacy. These broader dynamics may be particularly important for evaluations of community-based DCS serving individuals at higher-risk, given the complex relationship between information provision and health behaviour change which may be mediated by mental and physical health, stigma, criminalisation and the risk environment. This paper is of international relevance and adds to existing literature on the potential impact of DCS on individuals, organisations, and public health structures.

A strategy for the detection of benzodiazepine drugs using low-resolution paper-spray mass spectrometry for harm reduction drug checking.

The ability to detect newly emerging substances is of great importance in reducing harms for people who use drugs. New psychoactive substances including novel benzodiazepines in the illicit drug supply have been linked to high rates of overdose deaths while complicating drug checking as an overdose prevention strategy. Paper-spray mass spectrometry (PS-MS) has emerged as a novel strategy to rapidly detect trace components in street drug samples. While targeted, low-resolution PS-MS methods have proven effective, newly emerging substances are often missed. To address this, a method was applied to low-resolution full-scan PS-MS data to aid in the early detection and identification of novel benzodiazepines in the unregulated drug supply. Using the developed method, true positives rates of 0.89 and 0.75 were achieved for bromazolam and etizolam in street samples obtained in a community drug checking service. The applicability of the method was further demonstrated for a novel benzodiazepine, desalkylgidazepam, that has recently emerged in the illicit drug supply.

'It's not going to be a one size fits all': a qualitative exploration of the potential utility of three drug checking service models in Scotland.

BACKGROUND: Scotland currently has the highest rates of drug-related deaths in Europe, so drug checking services are being explored due to their potential role in reducing these deaths and related harms. Drug checking services allow individuals to submit presumed psychoactive drug samples for analysis, and then receive individualised feedback and counselling. This paper explores participants' views on the advantages and challenges of three hypothetical service models, to inform future service delivery in Scotland. METHODS: Semi-structured interviews were conducted with 43 people: 27 professional stakeholders, 11 people with experience of drug use, and five family members across three cities. Vignettes were used to provide short descriptions of three hypothetical service models during the interviews. Interviews were audio-recorded, transcribed and analysed using thematic analysis. RESULTS: Participants identified advantages and challenges for each of the three potential service models. The third sector (not-for-profit) model was favoured overall by participants, and the NHS substance use treatment service was the least popular. Participants also noted that multiple drug checking sites within one city, along with outreach models would be advantageous, to meet the diverse needs of different groups of people who use drugs. CONCLUSIONS: Drug checking services need to be tailored to local context and needs, with a range of service models being possible, in order to meet the needs of a heterogeneous group of people who use drugs. Addressing issues around stigma, accessibility, and concerns about the potential impact of accessing drug checking on access to and outcomes of drug treatment, are essential for successful service delivery.

Point-of-care community drug checking technologies: an insider look at the scientific principles and practical considerations.

Drug checking is increasingly being explored outside of festivals and events to be an ongoing service within communities, frequently integrated within responses to illicit drug overdose. The choice of instrumentation is a common question, and the demands on these chemical analytical instruments can be challenging as illicit substances may be more complex and include highly potent ingredients at trace levels. The answer remains nuanced as the instruments themselves are not directly comparable nor are the local demands on the service, meaning implementation factors heavily influence the assessment and effectiveness of instruments. In this perspective, we provide a technical but accessible introduction to the background of a few common drug checking methods aimed at current and potential drug checking service providers. We discuss the following tools that have been used as part of the Vancouver Island Drug Checking Project in Victoria, Canada: immunoassay test strips, attenuated total reflection IR-absorption spectroscopy, Raman spectroscopy from powder samples, surface-enhanced Raman scattering in a solution of colloidal gold nanoparticles, and gas chromatography-mass spectrometry. Using four different drug mixtures received and tested at the service, we illustrate the strengths, limitations, and capabilities of such instruments, and expose the scientific theory to give further insight into their analytical results. Each case study provides a walk-through-style analysis for a practical comparison between data from several different instruments acquired on the same sample. Ideally, a single instrument would be able to achieve all of the objectives of drug checking. However, there is no clear instrument that ticks every box; low cost, portable, rapid, easy-to-use and provides highly sensitive identification and accurate quantification. Multi-instrument approaches to drug checking may be required to effectively respond to increasingly complex and highly potent substances demanding trace level detection and the potential for quantification.

Carfentanil structural analogs found in street drugs by paper spray mass spectrometry and their characterization by high-resolution mass spectrometry.

Carfentanil is one of the most potent synthetic opioids ever developed, with an estimated analgesic potency approximately 20-100 times that of fentanyl and 10,000 times that of morphine. Carfentanil has been appearing in the illicit drug supply in many regions and has been linked to fatal overdose events. A subset of 59 street drug samples obtained in Victoria, B.C., that were confirmed to contain carfentanil were analyzed by mass spectrometry for this study. Carfentanil quantitation by paper spray mass spectrometry ranged from 0.05 to 2.95 w/w% (median = 0.32%) in the original drug sample. Paper spray mass spectrometry analysis also detected two unknown peaks at m/z 380.2 and 381.2 in 31 of these 59 samples (53%). Initial tandem mass spectrometry experiments revealed structural similarities between these unknown compounds and carfentanil, suggesting they were potential structural analogs, possibly arising from incomplete purification during synthesis. High-resolution mass spectrometry determined the chemical formulas of these compounds as C23 H29 N3 O2 (m/z 380.2333) and C23 H29 N2 O3 (m/z 381.2137). Literature and tandem mass spectrometry results were used to determine the identity of these potential new psychoactive substances, C23 H29 N3 O2 as desmethylcarfentanil amide and C23 H29 N2 O3 as desmethylcarfentanil acid. µ-Opioid receptor binding modeling determined that the binding poses of these analogs were nearly identical to that of carfentanil with relative binding energy calculations of 0.544 kJ/mol (desmethylcarfentanil amide) and -0.171 kJ/mol (desmethylcarfentanil acid); these data suggest they may share the toxic effects of carfentanil and have similar potencies.

Substance Use Stigma and Community Drug Checking: A Qualitative Study Examining Barriers and Possible Responses.

BACKGROUND: Community drug checking is an emerging response to the overdose crisis. However, stigma has been identified as a potential barrier to service use that requires investigation. METHODS: A qualitative study explored how best to implement drug checking services to the wider population including those at risk of overdose. A secondary analysis of 26 interviews with potential service users examine how stigma may be a barrier to service use and strategies to address this. A Substance Use Stigma Framework was developed to guide analysis. RESULTS: Drug checking is operating in a context of structural stigma produced by criminalization. People fear criminal repercussions, anticipate stigma when accessing services, and internalize stigma resulting in shame and avoidance of services. A perceived hierarchy of substance use creates stigma results in stigma between service users and avoidance of sites associated with certain drugs. Participants frequently recommended drug checking to be located in more public spaces that still maintain privacy. CONCLUSIONS: Criminalization and societal views on substance use can deter service use. Strategies to mitigate stigma include employment of people with lived and living experience from diverse backgrounds; public yet private locations that preserve anonymity; and normalization of drug checking while decriminalization could address the root causes of stigma.

Evaluation of Respiratory Sounds Using Image-Based Approaches for Health Measurement Applications.

Goal: The evaluation of respiratory events using audio sensing in an at-home setting can be indicative of worsening health conditions. This paper investigates the use of image-based transfer learning applied to five audio visualizations to evaluate three classification tasks (C1: wet vs. dry vs. whooping cough vs. restricted breathing; C2: wet vs. dry cough; C3: cough vs. restricted breathing). Methods: The five visualizations (linear spectrogram, logarithmic spectrogram, Mel-spectrogram, wavelet scalograms, and aggregate images) are applied to a pre-trained AlexNet image classifier for all tasks. Results: The aggregate image-based classifier achieved the highest overall performance across all tasks with C1, C2, and C3 having testing accuracies of 0.88, 0.88, and 0.91 respectively. However, the Mel-spectrogram method had the highest testing accuracy (0.94) for C2. Conclusions: The classification of respiratory events using aggregate image inputs to transfer learning approaches may help healthcare professionals by providing information that would otherwise be unavailable to them.

Everywhere and for everyone: proportionate universalism as a framework for equitable access to community drug checking.

BACKGROUND: Illicit drug overdoses have reached unprecedented levels, exacerbated by the COVID-19 pandemic. Responses are needed that address the increasingly potent and unpredictable drug supply with better reach to a wide population at risk for overdose. Drug checking is a potential response offered mainly within existing harm reduction services, but strategies are needed to increase reach and improve equitable delivery of drug checking services. METHODS: The purpose of this qualitative study was to explore how to extend the reach of drug checking services to a wide population at risk of overdose. We conducted 26 in-depth interviews with potential service users to identify barriers to service use and strategies to increase equitable delivery of drug checking services. Our analysis was informed by theoretical perspectives on equity, and themes were developed relevant to equitable delivery through attention to quality dimensions of service use: accessibility, appropriateness, effectiveness, safety, and respect. RESULTS: Barriers to equitable service delivery included criminalization and stigma, geographic and access issues, and lack of cultural appropriateness that deter service use for a broad population with diverse needs. Strategies to enhance equitable access include 1ocating services widely throughout communities, integrating drug checking within existing health care services, reframing away from risk messaging, engaging peers from a broad range of backgrounds, and using discrete methods of delivery to help create safer spaces and better reach diverse populations at risk for overdose. CONCLUSIONS: We propose proportionate universalism in drug checking as a guiding framework for the implementation of community drug checking as an equity-oriented harm reduction intervention and as a population health response. Both a universal equity-oriented approach and multiple tailored approaches are required to facilitate drug checking services that maximize reach and appropriateness to respond to diverse needs.

A Realist Review of How Community-Based Drug Checking Services Could Be Designed and Implemented to Promote Engagement of People Who Use Drugs.

With rising numbers of drug-related deaths in the UK and globally, exploration of interventions that seek to reduce drug-related harm is essential. Drug checking services (DCS) allow people to submit drug samples for chemical analysis and receive feedback about the sample, as well as harm reduction advice. The use of DCS is often linked to festival and/or nightlife settings and to so-called 'recreational' drug use, but research has also shown the potential of community-based DCS as an intervention serving more varied demographics of people who use drugs, including more marginalised individuals and those experiencing drug dependence. Whilst there is a growing evidence base on the effectiveness of drug checking as a harm reduction intervention, there is still limited evidence of the underlying mechanisms and processes within DCS which may aid implementation and subsequent engagement of people who use drugs. This presents a challenge to understanding why engagement differs across types of DCS, and how best to develop and deliver services across different contexts and for different populations. To explore the contexts and mechanisms which impact engagement in community-based DCS, a realist review was undertaken to synthesise the international evidence for the delivery and implementation of DCS. There were 133 sources included in the review. From these sources the underlying contexts, mechanisms, and outcomes relating to DCS implementation and engagement were developed and refined into seven programme theories. The findings of this review are theoretically novel and hold practical relevance for the design of DCS, with implications for optimisation, tailoring, and implementing services to reach individuals in different settings.

Challenges for drug checking services in Scotland: a qualitative exploration of police perceptions.

BACKGROUND: The impact of policing practices on the engagement of people who use drugs (PWUD) with harm reduction services is well evidenced. Although the police have traditionally taken an enforcement role in responding to drug use, it is increasingly clear that they can play an important part in multiagency delivery of harm reduction interventions. Despite this, there have been no studies exploring police officer perceptions of drug checking services (DCS), which provide analytical testing of client drug samples alongside harm reduction support and advice. METHODS: Semi-structured interviews were conducted with 10 police officers to explore the policing and legal challenges which could be encountered in the delivery of DCS in Scotland. RESULTS: Participants expressed general support for DCS and described this support as part of a wider organisational shift towards public health-oriented policing. Participants also discussed different potential approaches to the policing of areas surrounding DCS including: formal limits on police presence around the service and/or stop and search powers in relation to personal possession; the effective decriminalisation of personal possession within a specified boundary around the service; and informal agreements between local divisions and DCS outlining expected policing practices. Any formal limitation on the capacity of police officers to respond to community concerns was viewed as problematic and as having the potential to erode public confidence in policing. Participants also highlighted the potential for frontline officers to utilise discretion in ways which could undermine public health goals. Legislative change, or national strategic guidance from relevant stakeholders, was seen as a means of providing 'cover', enabling local divisions to support the operation of drug checking. CONCLUSIONS: Despite a small sample of participants, this study summarises key challenges to be addressed in the implementation and operation of DCS in Scotland, and more widely. The paper concludes with suggested opportunities to develop approaches to policing that can facilitate rather than impede implementation and operation of these services.

Exploring the use of infrared absorption spectroscopy and two-trace two-dimensional correlation analysis for the resolution of multi-component drug mixtures.

Community drug checking provides an essential service that responds to the unpredictable and variable supply of illicit drugs. Point of care detection of trace components using portable infrared spectrometers is a harm reduction measure to prevent overdose. This study investigates the ability of weighted subtraction and two-trace two-dimensional (2T2D) correlation analysis to reveal the presence of heroin in an opioid mixture that contains heroin and fentanyl mixed with caffeine as a cutting agent. In both methods, a spectral trace was identified that provided reasonably high correlation scores to heroin when compared to entries in drug libraries. The two-trace correlation analysis produced a higher match score, suggesting that future improvements in spectral unmixing methods may enhance the reliability of detecting trace components in drugs.

Variability in the unregulated opioid market in the context of extreme rates of overdose.

BACKGROUND: Drug checking uses analytical chemistry technologies to report on the composition of drugs from the unregulated market to reduce substance use-related risks, while additionally allowing for monitoring and reporting of the supply. In the context of an overdose crisis linked to fentanyl, we used drug checking data to examine variability within the illicit opioid supply. METHODS: In this time-series analysis, data was collected from a drug checking service in Victoria, Canada from November 2020 to July 2021. Drugs reported as opioids by participants of the service (N = 454) were analyzed to determine sample composition and paper spray mass spectroscopy was used to quantify low-concentration actives. Interquartile and statistical process control (SPC) analysis, namely standard deviation control charts, were used to examine the degree of variability among samples. RESULTS: Fentanyl was found in 96% of samples reported to be opioids, with a median concentration of 9%. Concentrations varied significantly, with a standard deviation of 7% for fentanyl and where nearly 20% of data points fell outside the control limits. Over half of the samples contained an additional and unexpected active, most commonly etizolam (43% of samples). Etizolam also showed a large level of variability, uncorrelated to that of fentanyl. CONCLUSIONS: Based on our chemical quantification and SPC analysis, a high degree of variability was found in opioid samples from the unregulated market in both the drugs detected and the concentrations of those drugs. This demonstrated the opioid crisis to be less attributable to a bad batch of drugs but rather the general variability found in the unregulated market.

Rapid and accurate etizolam detection using surface-enhanced Raman spectroscopy for community drug checking.

BACKGROUND: In British Columbia, Canada, illicit opioids have been increasingly combined with etizolam, a benzodiazepine analog, that continues to challenge popular portable drug checking technologies as it is often present in low concentrations as a result of its high potency. An unknown combination of opioids and benzodiazepines may have dangerous consequences due to unpredictable dosing, increased respiratory depression, and complicated overdose response measures. METHODS: Surface-enhanced Raman spectroscopy (SERS) using a portable Raman spectrometer is used to establish a univariate model for the detection of etizolam in opioid drug mixtures (n=100) obtained from the Vancouver Island Drug Checking Project, where the presence of etizolam has been determined using paper-spray mass spectrometry. Benzodiazepine immunoassay test strips are also performed on all samples for comparison. RESULTS: SERS is shown to detect etizolam with high sensitivity (96%) and specificity (86%). In contrast, benzodiazepine test strips demonstrate a low sensitivity (8%) for the detection of etizolam of the same samples (n=100), with only small improvements when studied over a larger subset of samples (n=506, sensitivity = 29%). CONCLUSION: We have demonstrated the potential of SERS for trace detection of etizolam within complex sample matrices. Since SERS is one of the few portable technologies capable of trace detection, further studies on its ability for quantification and discrimination of trace adulterants in street samples is of significant interest for point-of-care applications.

Third party drug checking: accessing harm reduction services on the behalf of others.

BACKGROUND: Drug checking uses chemical analytical technologies to analyze drugs from the unregulated market to reduce substance use-related risks. We aim to examine the frequency of third party use of a community drug checking service to explore the potential for harm reduction to extend beyond the individual into the community, increase service accessibility, and to contribute to upstream interventions in the supply. METHODS: Over 31 months, data were collected from a point-of-care drug checking service operated in Victoria, Canada. Through the implementation of survey questions at the intake of the service, data were collected about whether the drug check was for the individual, to sell, and/or for others. RESULTS: Just over half (52%) of service users were checking for reasons that extended beyond individual use. When checking for others, friends were the most common response, representing 52% of responses, and outreach/support workers checking for others was the second most at 32%. Twelve percent of service users reported checking to sell or for a supplier. CONCLUSIONS: Third party checking is a frequent, and important aspect of drug checking services, which through facilitating community engagement and increasing accessibility, has expanded the reach of interventions beyond individuals to reduce risks within the unregulated market. Therefore, drug checking as an overdose response should be responsive and accessible for those using the service on the behalf of others.