Providers presented a picture of the drug market as a moving target, characterized by rapid changes in localized drug supply content and associated rates of overdose. Drug checking services provide users with information about the risk of taking the respective drug compound tested and can influence drug-taking behaviors [65]. Indeed, as seen in the interviews conducted, drug checking services have been instrumental in monitoring and providing information to PWUDs about the presence of the highly potent synthetic opioid fentanyl, a product that has come to dominate the illicit drug market in a number of regions across North America [19,35,36,39–43]. Bearing witness to ever-changing drug markets, there is increasing concern over the presence of the veterinary tranquilizer xylazine within both the USA and Canada [66,67], and novel psychoactive substances of concern continue to emerge, requiring timely monitoring.
Overall, providers’ depictions of the illicit drug market highlight the need for drug checking as a key mechanism to reduce risks to PWUDs while emphasizing the ‘bootstrap’ nature of the implementation of these programs. In addition to providing individuals with vital information about potential drug risks, drug checking data can provide both formal and informal (word of mouth) warnings about contaminants and/or drug variants that may pose risks to the larger community [11,12,14,15]. In Canada, drug checking is increasingly used as a monitoring and surveillance tool, while other forms of drug supply surveillance have been suggested elsewhere [34,68]. It is notable how drug checking services emerged in the context of drug prohibition, creating an unregulated drug market where, outside of some law enforcement channels and limited public health surveillance, information about the drug supply is highly limited. Drug checking as a response to this sparse and sometimes guarded knowledge is not a monolith, but rather an amalgamation of established and novel services that seek to provide useful and actionable information about the drug supply. In short, drug checking services provide a key source of information for monitoring and acting upon changes in local drug markets.
While mindful of the promise that drug checking provides in terms of increasing individual- and community-level knowledge, drug checking providers recognized that drug checking is an imperfect enterprise, limited with respect to the available technology (and associated financial costs), the lack of combined technical and communication exper- tise requirements, and the legal landscape. With respect to the available technology (and reflecting the current literature), provider interviews highlighted that there is no single technology that can cope with ever-changing drug markets. While FTSs are cost-effective, can reliably identify fentanyl as a contaminant in other drugs, and are a useful component in a constellation of drug checking technologies, they identify only one compound among many and cannot offer quantitative data [39,49,69,70]. In addition, the utility of FTSs is reduced for those who prefer fentanyl or who are getting “fatigued” by needing to test frequently. By way of contrast, spectrometry provides information as to the overall content of the sample provided by drug users and can provide quantification as well, but the equip- ment is expensive, requires training to analyze the results, and the machines are limited with respect to their sensitivity (i.e., 5% by weight) and mobility [10,17,37,38,44–46,50]. To balance the pros and cons of each piece of technology, many programs are combining the greater sensitivity of FTSs (as well as immunoassay test strips for other drugs, e.g., benzodiazepines and xylazine) with the greater specificity of spectrometry in their drug checking algorithms.
Even if a single perfect technology was available, its costs, in terms of staffing and equipment, along with the need to provide integrated comprehensive health and social services for PWUDs remain challenging for most programs. Individual spectrometry machines were reported to cost approximately USD 50,000, but it is also clear that a single machine is not sufficient to cover a city the size of San Francisco (population~800,000), let alone Los Angeles (population~3,800,000). As such, it can be assumed that newly launched drug checking services would require significant funding support on a long-term basis and be in locations where PWUDs are best suited to access services [10,37,47,50]. Any upscaling efforts will require knowledge of how many machines (such as FTIR) would be needed to meet the requirements of a particular location (noting that some might need to be used in mobile units) and the upfront costs associated with these machines (and associated physical infrastructure), as well as training, operation, and maintenance costs.
Closely associated with technology and costs, providers pointed to a bottleneck or even crisis with respect to the staff needed to operate a successful drug checking program. Providers highlighted both the paucity of resources devoted to harm reduction programs generally, as well as the issue of training on and operating devices that require a high initial level of technical skill. Our study participants were divided on the appropriate level of technical skill as well as drug supply know-how needed to successfully operate and interpret the readout provided by a machine, such as an FTIR machine [64,71,72]. Finding appropriately trained individuals who are also knowledgeable about the drug supply and sympathetic to the issues faced by people who use drugs is likely to be challenging. Addi- tionally, there is an urgent need, as participants noted, for developing training materials and technical support for the harm reduction organizations operating these programs. Asking that drug checking technicians, who are not deeply rooted in harm reduction practices, relay complicated information about drugs to clients is by no means easy, but participants were confident that training could be provided in this dual role of technical analyst and communicator. It is possible that a national training center and organizational hub could be leveraged as a resource for both technical support for drug checking technologies and communication expertise, as well to aggregate timely on-the-ground information about vicissitudes in the drug supply.
Underpinning these imperfections in technology and limitations in terms of scaling up service provision are the political and legal landscapes. Interviewees’ concerns regarding policy and policing reflect the considerable variation in the legal and policing context of drug checking within and outside of the USA [3,53–56]. The legal status of drug checking mentioned by some participants adds to the climate of uncertainty drug checking pro- grams operate under. In Canada, for example, federal exemptions have been granted to implement drug checking services, but the process is time-consuming and fraught with lo- gistical difficulties. Such uncertainty makes providers wary and, for structurally vulnerable communities, may reduce the likelihood of use [48,50,51,64].
Drug checking services suffer from an overall lack of official support at the state or federal levels, although several recent programs have launched in the USA that enjoy local support. Even in Canada, which has implemented drug checking for longer than the USA, many of these programs operate under temporary emergency authorizations, rather than enjoying guaranteed federal, state, and local support. On follow-up with a Canadian provider, funding for their program in Ontario is scheduled to run out at the end of March 2023, and no government or non-governmental entity has stepped up to provide long-term funding, leaving the staff uncertain in their job security and putting the community that this program serves in greater jeopardy. This speaks to the fundamental need for greater consistency in the policy and policing environment to enable providers some security that they will be allowed to provide this service above and beyond temporary exemption orders. Without such assurance, not only will PWUDs and providers be left in legal limbo, but it will remain difficult to find funding to pay for the necessary equipment and training investments without being able to plan for the future. Overall, if the legal status of drug checking remains as it is, drug checking services will continue to operate through temporary exemption orders and gray areas in the law, neither of which are compatible with meeting the long-term harm reduction objectives which encompass these initiatives [2,6,12,17,73].
Service providers showed considerable caution about how the impact of drug checking services should be measured, especially in terms of reducing overdose rates. Indeed, the question of whether providing drug checking findings to participants necessarily influences behavior change, directly reduces overdose rates, or improves uptake in substance use treatment programs cannot easily be answered at this time [13,15,42,74–76]. Nevertheless, the benefit in providing drug supply knowledge to PWUDs was one of the more dominant narratives emerging from the interviews. Knowing the content of their respective drug supply was seen as empowering, giving people with little say in the illicit drug supply a greater sense of control over their life and choices, including the choice to modify use, change drug sellers, and/or seek out further harm reduction services. As such, directly linking the success of drug checking services to overdose prevention may be unnecessarily reductive and counter-productive to the broad objectives of drug checking given the multiple indirect pathways by which these broad services may contribute to overdose prevention [1,10,11].
The success of drug checking services may be seen with individuals choosing to discard their drugs or reduce the frequency or amount taken to avoid likely harm [12,65,77], a change that could be life-saving but may be impossible to monitor and not always an option for those with few resources [41,48]. Other harm reducing behaviors include use of “tester shots” [78], carrying naloxone, not using alone, and using in the context of a supervised consumption space. However, even if behavioral change is not possible or not measurable, drug checking can still be empowering in linking individuals who use drugs to harm reduction services, including substance use treatment, HIV/HCV testing, housing assistance, supervised consumption sites, and medical care.
The access and engagement of PWUDs with other harm reduction services were viewed as key indicators of the success of drug checking programs. The collaborative nature and “meet people where they are at” sensibility of harm reduction programs were identified by many as particularly strong reasons to co-locate drug checking services within harm reduction programs, a finding not limited to participants directly employed in such organizations. Relationship building with participants was also a notable strength of harm reduction organizations identified in this research. In the case of those who have had negative, stigmatizing experiences with respect to policing, social attitudes, and/or when receiving healthcare services, drug checking in these venues can provide a foundation for engagement and trust building. From this point of trust, drug checking providers may be able to establish themselves (or their colleagues) as advocates for individuals wanting to access and navigate through health and social services that improve health outcomes.
Issuing public-facing warnings about drug supply variability remains challenging. At present, systems that provide warnings about ‘bad batches’, such as text-based warning systems seen in Baltimore, Maryland, USA [79] and in British Columbia, Canada [80], are generated from reported overdoses, including EMS data, rather than based on drug supply knowledge from drug checking. One potential measure of outcome success of warning programs would be a greater and more detailed ability to warn PWUDs about specific supply changes, including batch/brand warnings, appearance cues, and possible side effects and health risks. Early communication of drug checking findings across state and region may be another measure of success, while also acknowledging that local context is extremely important for understanding trends in drug contaminants. However, better monitoring through drug checking might also be instructive in building understanding about drug supply across cities, states, and regions. Another measure of success might be increases in the use of drug checking and/or associated harm reduction services. Other measures could include referrals from drug checking to HIV/HCV testing, first aid and wound care, and housing stabilization programs. Such information could be fed back to the drug user community as an indication of the benefits of drug checking and how drug checking can improve wellbeing. Moreover, they can be used as measures of success to demonstrate the utility of drug checking to policy makers and the general public who are sometimes hostile to drug checking and associated harm reduction measures [81].
Potential limitations of this study include its geographic restriction to North America. Drug checking is underway in many USA and Canadian localities, but its tenuous legal status makes recruitment of individuals working in drug checking particularly fraught. Snowball and targeted sampling of individuals working in a range of settings sought to address this limitation. Additionally, the lack of inclusion of the perspectives of PWUDs is another limitation. A companion manuscript from this study is in preparation that will explore perspectives of both providers and PWUDs on the feasibility of using drug checking services in the USA and report on the experiences some have already had with these services.