The results of this study demonstrate that many young PWUD at risk of a fentanyl overdose perceive FTS as a feasible and acceptable harm reduction tool. In this study, we assessed two different applications of FTS (urine testing and residue testing) and found that residue testing is more convenient and allowed for participants to know about fentanyl adulteration before drugs are consumed. The majority of participants suggested that FTS were straightforward to use and did not cite significant barriers to use. After receiving a positive test result, many participants described precautions that they believed would prevent an overdose, such as using a drug with others around, keeping naloxone nearby, or using a tester. These findings suggest FTS may represent an important harm reduction intervention for opioid overdose prevention among young adult PWUD.
While there are other methods confirming the presence of fentanyl in one’s drug supply, such as the use of Raman spectroscopy and FTIR spectroscopy, prior research has found that the BTNX Inc. Rapid Response™ Fentanyl Testing Strips have higher specificity and sensitivity and are significantly less expensive than other methods [46]. Nonetheless, testing illicit drugs, through either FTS or chemical analyses, has proven to be an effective approach in identifying adulterants that pose added overdose risk to PWUD, as indicated by ongoing drug checking efforts in Canada and in European countries [24, 27].
In places where drug testing is legal, such as Canada and Europe, people who want to have their drugs tested most often need to bring their substances to specific locations. For instance, SIFs in Canada distribute FTS to their clients; however, clients must test their drugs in that same setting [51,52,53]. In Europe, drug testing largely takes place at music venues and mobile test sites with trained professionals [27, 54]. In contrast, syringe service programs (SSPs) in the US are just beginning to disseminate FTS to their clients for at-home use outside of a clinical or supervised context [40, 41]. State governments and departments of health, such as those in California, Vermont, and Maine, are also providing funding for the purchase and dispersal of take-home FTS through existing SSPs [37,38,39, 42]. However, there are debates as to whether there is sufficient evidence to support the effectiveness of home testing programs [32]. Given that FTS have the potential to return false negative results, PWUD using FTS may proceed to use their drugs without added precautions to prevent fentanyl overdose risk even if their drugs are contaminated with fentanyl. Outside of monitored environments such as at SIF, a false negative test in a private setting could lead to a higher risk of overdose [34]. To mitigate this concern, all participants were instructed during the FTS training that false negatives are possible and that a negative result does not necessarily mean an absence of overdose risk. Private use of FTS (i.e., outside of monitored environments) may represent a novel harm reduction strategy to reduce the risk of fentanyl-related overdose, even though concerns persist regarding the risk for unintentional overdose resulting from a false negative [34].
Harm reduction technologies used in private settings have appeal to PWUD in the US who fear the legal ramifications and stigma associated with use of harm reduction services, such as SSPs [55, 56]. In agreement with US studies that have found that harm reduction service can be uncomfortable and unapproachable for some PWUD, particularly for young adults, our participants recounted their reluctance to engage in FTS use at professional agencies or harm reduction organizations [57,58,59]. Our study suggests that young PWUD are comfortable using FTS on their own and would prefer to use them either in their own home or in another private setting due to concerns for privacy and fear of arrest and facing stigma from the public, found to be a significant barrier to harm reduction uptake in earlier studies [58]. Furthermore, secondary distribution of FTS, mirroring documented occurrences of secondary distribution of sterile syringes, has the potential to benefit PWUD who are either uncomfortable accessing or are not closely engaged to healthcare services [60, 61]. Collectively, these findings indicate that interventions which permit drug checking in private environments may potentially increase accessibility and acceptability of drug testing among young PWUD. Additionally, our participants may have used take-home FTS as this intervention allows for self-efficacy and peer-to-peer interaction, which have been found to lead to successful implementation harm reduction programs in previous research [57].
Upon receiving a positive FTS result, many participants were motivated to engage in various harm reduction techniques, including using a smaller dose, having naloxone nearby, using the drug with someone else around, or disposing of their drugs entirely. Consistent with another study of FTS conducted in the US [35], participants stated they employed these precautions because they were made aware of fentanyl contamination. Prior studies of self-testing technologies suggest similar results—that is, rapid self-testing may contribute to an increase in harm reduction behaviors. Multiple studies on rapid self-testing for HIV, a technology that was legalized for at-home use in the US in 2012, have reported noticeable increases in both perceptions of risk and target risk reduction behaviors [62,63,64,65]. Additionally, studies have shown HIV self-testing is a successful intervention for increasing routine HIV testing among hard to reach and hard to engage populations, such as young adults engaging in high-risk behaviors [66, 67]. Such findings offer promise for rapid testing technology as a key component of harm reduction interventions for fentanyl overdose. Furthermore, in Canadian studies of FTS, and in initial studies of FTS in New York City, participants who received a positive FTS result changed their behavior in similar ways to the current study; they slowed down their use, used a smaller dose, or disposed of the drug that was found to contain fentanyl [25, 26, 42]. Given these results, FTS should be explored as an additional means of preventing opioid overdose used in tandem with other harm reduction measures, such as naloxone distribution and overdose education. In contrast, it has been hypothesized that in areas where fentanyl contamination is pervasive, PWUD who have taken drugs that contain fentanyl and have not experienced an overdose may become complacent in their use of overdose prevention strategies [34]. This could prove to be true in Rhode Island where participants noted that fentanyl contamination is likely. Ultimately, future research is needed to evaluate FTS interventions to understand how FTS may contribute to behavior change among young adults.
This study had a number of limitations. First, as the average follow-up time frame was less than a month, some participants did not have an opportunity to try the FTS, given that some reported a lack of opportunity to either buy or use the drugs in the study’s timeframe. Many of the participants who had not used FTS during the study had expressed that given a longer time frame for use, they would have tried the FTS. Future research regarding fentanyl FTS should include a longer period between the provision of the FTS and follow-up. Second, though interviews varied in length, they generally did not last more than 15 min. Beyond this pilot project, future studies could conduct longer interviews with participants, which may allow for a more nuanced understanding of the influence and effect of FTS utilization on behavior change among young PWUD. Third, discussions of how drug use changed following a positive FTS result could be affected by social desirability bias. Additionally, selection bias may have occurred due to healthy screenee bias [68], in which PWUD who want to avoid fentanyl may be more likely to enroll in a study of FTS. Nonetheless, our results suggest that participants altered their drug behavior as a result of having a definitive knowledge that their drug contained fentanyl. Fourth, while we ascertained that many of the participants had a history of homelessness, we did not ask if participants faced challenges of using FTS due to current housing instability or homelessness. Therefore, we cannot make claims about FTS usability among those currently experiencing homelessness. Finally, this study took place in Rhode Island, a state with a high burden of fentanyl-related overdoses and fentanyl contamination. As such, results may not be generalizable to other settings, particularly those in which the presence of fentanyl contamination in illicit drugs is less common.