Skip to main content

Characteristics and context of fentanyl test strip use among syringe service clients in southern Wisconsin



Fentanyl adulteration of illicit drugs is a major driver of opioid-involved overdose in the USA. Fentanyl test strips are increasingly used by people who use drugs to check for fentanyl. However, little is known about factors that influence test strip use in this population.


In this mixed-methods study employing semi-structured open-ended interviews (n = 29) and a structured survey (n = 341), we examined characteristics associated with test strip use, characteristics of test strip use, and situational, logistical and psychosocial factors influencing test strip use. Respondents were recruited from a syringe service program in southern Wisconsin. Bivariate tests of association and multivariable logistic regression examined the relationship between respondent characteristics and test strip use. Summary statistics were used to describe how situational, logistical and psychosocial factors impact test strip use.


Most respondents were male (59.6%), non-Hispanic white (77.4%), young (mean 35.7 years), reported heroin as their primary drug (70.7%), injection as their primary route (87.9%), and use ≥ 3 times daily (78.6%). In multivariable models, site, race and ethnicity, drug of choice, and seeking fentanyl were associated with test strip use. Among test strip users, 36.5% use them most of the time or more and 80.6% get positive results half the time or more. Among individuals reporting heroin, fentanyl, methamphetamine, or cocaine or crack cocaine at least once per month, 99.1%, 56.8%, 42.2%, and 55.7% reported testing these drugs, respectively. Test strip use is supported by information from suppliers, regular transportation, diverse distribution locations, recommendations from harm reduction staff, and having a safe or private place to use.


We found that individuals who use fentanyl test strips are more often non-Hispanic white, use heroin, and seek drugs with fentanyl relative to individuals without test strip use. Findings confirm high fentanyl penetration in the Wisconsin drug supply. Low rates of stimulant testing suggest inadequate awareness of fentanyl penetration. Findings support outreach to key populations, increased diversity of distributing locations, efforts to correct misperceptions about drug wasting, emphasis on pre-consumption testing, and the importance of adjunct behaviors to prevent overdose given high rates of intentional fentanyl use.


Since 2000, opioid overdose deaths have surged from 6.2 per 100,000 persons [1] to 21.6 per 100,000 persons in 2019 [2]. This astounding rise has been primarily driven by adulteration of the illicit drug supply with potent synthetic opioids, namely fentanyl and its analogs [3, 4]. Treatment with medications for opioid use disorder (OUD) reduces opioid overdose mortality [5, 6]. Yet, less than 30% of the 2 million people living with OUD receive treatment, reflecting diverse barriers to treatment services [7, 8]. Consequently, affordable alternative approaches are critically needed to reduce opioid overdose.

Fentanyl test strips (FTS) are a harm reduction tool available to people who use drugs (PWUD). Originally an immunoassay for urine drug testing [9], FTS can detect fentanyl and some analogs in drug solution [10]. Harm reduction organizations have been distributing FTS to PWUD for the purposes of drug checking [9, 11,12,13,14,15]. Literature on feasibility and impact of FTS suggests that FTS may allow PWUD to reduce opioid overdose risk [9, 12]. For example, FTS use is associated with using less, injecting more slowly, using a test dose, and not using alone [9, 11, 12, 16]. FTS are also affordable and easily distributed where legal [17, 18].

Despite promising findings, challenges exist to FTS expansion. For example, stigma can discourage individuals from seeking services where they might receive or learn about FTS [19]. Criminalization and fear of prosecution also limits access to harm reduction services [20]; paraphernalia laws make FTS possession a felony in some states [17, 18]. Social determinants create additional barriers since transportation and safe housing impact the ability to access and utilize FTS [21,22,23,24,25,26]. Generally, few locations offer FTS limiting access to this tool [25, 27].

Thus far, little research explores individual level and contextual factors impacting FTS use. Knowing more about who uses FTS and associated factors can help harm reduction organizations optimize their outreach and education around FTS. This paper addresses this gap by describing the characteristics of people who use FTS, the characteristics of FTS use, and the situational, logistical and psychosocial factors that promote FTS use in southern Wisconsin.



Data for this study come from Screening for Adulterants like Fentanyl and Risks of Fentanyl Test Strip Use (SAFeR), a sequential exploratory mixed-methods study on drug use behaviors among people who do and do not use FTS to test drugs for fentanyl. Phase 1 involved thematic analysis of interview data from semi-structured, open-ended interviews. Phase 2 incorporated content and language from Phase 1 into a survey focused on FTS use and related behaviors for distribution in a separate, larger sample. The study protocol was approved by the Institutional Review Board at the University of Wisconsin School of Medicine and Public Health (UWSMPH). SAFeR was funded by an internal grant through the Department of Family Medicine and Community Health, UWSMPH. This paper presents findings from Phase 2 survey data.

Respondents and recruitment

Respondents were recruited through a multi-state HIV prevention and treatment organization, which houses a syringe service program (SSP) that distributes supplies including FTS. At the time of study implementation, FTS were only available through this SSP for clients. Recruitment occurred at four SSP sites in Beloit, Kenosha, Madison, and Milwaukee through flyers and verbal advertisement. Each site offered comparable services though differed in size with the urban sites (Madison and Milwaukee) larger than the rural sites (Beloit and Kenosha) in terms of staffing, facilities and client population. Inclusion criteria required being ≥ 18 years, an existing SSP client (to avoid incentivizing drug use disclosure), at least 3 cumulative months of weekly nonprescribed substance use (excluding cannabis) and weekly use over the past 30 days, ability to speak and read in English, and, in Phase 2, ability to navigate a tablet-based survey. Exclusion criteria included previous participation and impaired cognition or safety concerns due to intoxication. In Phase 1, respondents provided verbal informed consent prior to interview. They received $30 at completion. In Phase 2, respondents provided digital consent within the survey. They received $15 at completion or $5 after failing inclusion/exclusion criteria.


Phase 1 data collection

Phase 1 aimed to identify topics and concerns among PWUD that might not be apparent from the published literature on FTS, and also to learn the language used by PWUD when discussing FTS. Specifically, Phase 1 consisted of in-depth interviews about behaviors impacting overdose risk, perceptions about fentanyl and FTS, factors influencing FTS use, and FTS-related communication among peers. The interview employed two types of questions: (1) non-directive, open-ended questions encouraging respondents to discuss concepts with minimal guidance from the researcher [28], and (2) directive open-ended questions aiming to gain depth of knowledge in several prespecified domains using free-listing [29]. Responses to non-directive questions provided insight into unexpected items for incorporation into the survey. For example, this approach identified fear of wasting drugs a common concern among respondents. Responses to directive free-listing items were tabulated across interviews to identify the most frequently mentioned items and to identify the point of saturation [29]. Interviews were conducted remotely via Cisco WebEx Web Conferencing with respondents on-site at their respective SSP via telephone. Five members of the study team led interviews, which were later transcribed by a professional transcription service. Interviews (n = 29) were conducted August—December 2020.

Phase 2 survey development and data collection

Content and language elicited in Phase 1 informed Phase 2 survey scope and content. Survey questions directly incorporated terminology and phrasing used by Phase 1 respondents. Survey questions prioritized topics (1) mentioned frequently, (2) relevant for overdose safety, and (3) perceived as actionable by the study team and SSP staff. Survey questions also asked respondents about situational, logistical and psychosocial factors influencing FTS use that were identified by Phase 1 respondents. These questions aimed to assess representativeness of these factors in a larger sample.

Data extraction from Phase 1 produced a 57-item questionnaire. Survey questions assessed demographic characteristics, drug use characteristics, FTS use characteristics, drug use behaviors, peer influences, perceptions of fentanyl and overdose risk, substance use treatment engagement, and factors impacting FTS use. Two items addressed misperceptions that emerged in Phase 1: needing to waste drugs to use FTS, and using FTS to look for fentanyl analogs. To prevent miseducating respondents, survey completion (and compensation) required that respondents confirm receipt of embedded educational material explaining that (1) using FTS does not require wasting drugs and (2) that FTS cannot reliably test for fentanyl analogs.

Surveys were self-administered without assistance from research and SSP staff on a tablet computer. Upon completion, survey data were automatically stored and protected from viewing or editing within the tablet. Data were subsequently transmitted and stored using Research Electronic Data Capture (REDCap) electronic data capture tools hosted at the UWSMPH Department of Family Medicine and Community Health. REDCap is a secure, web-based software platform designed to support data capture for research studies [30, 31]. In total, 341 surveys were collected March–September 2021.

Community engagement

Several external groups reviewed study materials. SSP staff and leadership provided feedback on interview and survey questions, study protocol, and recruitment strategy with respect to feasibility, comprehensibility, and importance. In addition, SAFeR TSU contracted a community-based research consultation group [Community Advisors on Research Design and Strategies (CARDS)] to review the Phase 2 survey and bring community voices to the process [32]. Importantly, CARDS includes a high proportion of members from communities historically marginalized and underrepresented in academic settings due to race or ethnicity, socioeconomic status, or educational attainment. While we did not ask members to confirm personal history of substance use, many members reported exposure through their community networks. Finally, the study team received itemized feedback on survey question structure and wording from the University of Wisconsin Survey Center.


Sociodemographic characteristics included age, gender (man, woman, nonbinary, trans, and other), race and ethnicity (American Indian or Alaskan Native, Asian, Black or African American, Hispanic or Latinx, Native Hawaiian or Other Pacific Islander, White, and other), education, employment, and self-reported county of residence. Urban county status was determined if at least half of the residents lived in census tracts with secondary Rural–Urban Commuting Codes of 1.0, 1.1, 2.0, 2.1, 3.0, 4.1, 5.1, 7.1, 8.1, and 10.1 [33].

Drug use characteristics included age at first drug use, drug of choice (herein, DOC-drug name), primary route of use, drug use frequency, polysubstance use, lifetime overdose count and recent treatments to stop or reduce drug use. Polysubstance use was defined as using one of the following substances at least monthly in addition to the DOC: heroin, fentanyl, opioid analgesics, synthetics, prescription anxiety medications, cocaine, crack cocaine, methamphetamine, prescription amphetamines or other.


Demographic characteristics were summarized for the sample. Associations between FTS use with demographic and drug use characteristics were determined using chi-square tests for nominal categorical variables and Mann–Whitney-Wilcoxon tests for continuous variables and categorical variables with natural ordering. Multivariable logistic regression examined associations between demographic characteristics and FTS use in adjusted models. Characteristics of FTS use were summarized for respondents who reported FTS use.

Analysis of situational and logistical factors influencing FTS use was limited to respondents who reported FTS use. Analysis of psychosocial factors influencing FTS use was assessed for the full sample. Likert responses were mapped from 0 to 4 and described by the mean and standard deviation. Associations of each factor with demographic and drug use characteristics (situational and logistical factors: 13 characteristics; psychosocial factors: 14 characteristics) were determined using Kruskal–Wallis tests for nominal variables and Jonckheere–Terpstra tests for ordinal variables (age, number of overdoses, years of drug use). Pairwise testing was conducted for significant results (p < 0.05) in which one of the variables consisted of three or more nominal categories. Mann–Whitney tests were used when the other variable was continuous or had a natural ordering, and chi-square tests were used when the other variable was categorical and nominal. No p value corrections for inflated type 1 error were used. All statistical analysis was conducted in R version 4.1.2 (2021-11-01).


Sample characteristics

Recruitment achieved even distribution across all sites (Table 1). Of 341 respondents, 274 reported using FTS or using drugs someone else tested with FTS. The average age was 35.7 years. Most respondents identified as men (n = 202, 59.6%) and non-Hispanic white (n = 263, 77.4%). Among respondents, 7.1% (n = 24) were non-Hispanic Black or African American, 6.2% (n = 21) were Hispanic, 2.9% (n = 10) were non-Hispanic American Indian, 1.8% (n = 6) reported other, and 4.7% (n = 16) reported multiple categories. Only 3.2% reported a 4-year college degree or more; 11.2% reported less than a high school degree. Nearly three-quarters (n = 243, 71.5%) reported unemployment in the past 6 months with desire for a job. Most identified intravenous use as their primary route (n = 299, 87.9%), DOC-heroin (n = 241, 70.7%), ≥ 3 times daily use (n = 268, 78.6%), and polysubstance use (n = 252, 73.9%). However, 43 respondents (12.6%) reported DOC-fentanyl. Respondents reported 4.4 lifetime opioid overdoses on average (SD = 8.4).

Table 1 Characteristics of SSP clients in southern Wisconsin with respect to FTS use

Individual-level associations with FTS use

In bivariate analyses, FTS was associated with SSP site, race/ethnicity, drug of choice, route of use, polysubstance use, and methadone use. Respondents who used FTS were more often clients in Milwaukee or Madison relative to Kenosha or Beloit (p = 0.016). Rates of FTS use were lower for non-Hispanic Black or African American respondents than non-Hispanic white or Hispanic respondents (p = 0.009). Respondents who reported DOC-opioid analgesics were less likely to use FTS than respondents with DOC-heroin, fentanyl, cocaine or crack cocaine, or methamphetamines (p < 0.001). FTS use was associated with seeking fentanyl (p = 0.009). Intravenous use was associated with FTS relative to snorting, smoking, and swallowing (p < 0.001). Polysubstance use (p = 0.020) and recent methadone treatment i (p = 0.029) were associated with FTS use. In contrast, gender, other recent treatments, frequency of drug use, years of drug use, overdose count, urbanicity, education, and employment status were not associated with FTS use. In multivariable regression, site, race and ethnicity, DOC, and seeking fentanyl were associated with FTS use. Specifically, relative to Milwaukee, respondents at Kenosha site were less likely to report FTS use (p = 0.009). Relative to non-Hispanic-white respondents, non-Hispanic Black or African American respondents were less likely to report FTS use (p = 0.006). Relative to DOC-heroin, DOC-opioid analgesic was associated with not using FTS (p < 0.001). More frequently seeking fentanyl was associated with FTS use (p = 0.009).

Characteristics of FTS use

Respondents who reported FTS use were asked additional questions about FTS. Respondents reported using FTS on average 26.7 (SD = 74.4) times, and using drugs tested by someone else 14.4 (SD = 64.9) times. Over one-third reported using FTS most of the time or more with their DOC. Nearly all respondents had received a prior positive FTS result (95.3%); fewer had received a prior negative result (70.8%). Over 80% reported positive results half the time or more with their DOC. Almost one-third reported test result confusion. In addition, 13.1% reported testing after use. Respondents reported testing a variety of drugs including cocaine (27.0%), crack cocaine (32.1%), fentanyl (36.9%), heroin (92.7%), cannabis (4.7%), methamphetamine (19.0%), opioid analgesics (11.3%), and stimulant medications (1.1%). Among those who reported at least monthly use of heroin (n = 235), fentanyl (n = 146), opioid analgesics (n = 80), methamphetamine (n = 90, 32.8%), and cocaine or crack cocaine, 99.1% reported testing heroin, 56.8% reported testing fentanyl, 16.3% reported testing opioid analgesics, 42.2% reported testing methamphetamine and 55.7% reported testing cocaine or crack cocaine, respectively. Notably, 61.3% reported using FTS to test for fentanyl analogs (Table 2).

Table 2 Characteristics of FTS use among SSP clients in southern Wisconsin

Situations prompting FTS use

Respondents were asked how often the following situations prompt FTS use: when you get a new baggie or batch, when your supplier puts out a new batch, your supplier says the batch is strong, and your drugs look different from what you have used before. For all situations, respondents reported using FTS some of the time to most of the time (Table 3). Specifically, the highest scores were observed when a supplier says the batch is strong (mean: 2.7; SD: 1.2) compared with getting a new baggie or batch (mean: 2.4; SD: 1.1). In analyses not shown, increased respondent age was associated with increased FTS use when the supplier says the batch is strong (p = 0.032). DOC-heroin was associated with increased FTS use when the supplier puts out a new batch (p = 0.038). Other sociodemographic and drug use characteristics were not associated with situational factors.

Table 3 Frequency of FTS use in specific situations among SSP clients in southern Wisconsin who use FTS

Logistical factors related to FTS use

Respondents were asked which of the following factors would make getting FTS easier: having test strips delivered to you, having regular transportation, getting more test strips at a time, and getting them at other locations (in addition to SSP). Respondents reported that all four factors would make it somewhat to quite a bit easier to get FTS (Table 4). Transportation and additional distribution locations exhibited the highest mean score (2.8). In analyses not shown, younger respondents reported increased ease of FTS access with delivery (p = 0.038) or regular transportation (p = 0.006) relative to older respondents. Respondents with polysubstance use also reported increased ease of FTS access with FTS delivery (p = 0.027). Respondents with DOC-heroin (p = 0.006), fentanyl (p = 0.001), and methamphetamine (p = 0.007) reported higher scores for receiving FTS from additional locations relative to respondents reporting DOC-cocaine or crack cocaine. Other sociodemographic and drug use characteristics were not associated with logistical factors impacting access to FTS (Table 5).

Table 4 Logistical factors impacting access to FTS among SSP clients in southern Wisconsin who use FTS
Table 5 Psychosocial factors impacting the likelihood of using FTS among SSP clients in southern Wisconsin

Psychosocial factors related to FTS use

Respondents were asked how likely the following factors would increase FTS use: recommendations to use FTS from a counselor or doctor, SSP staff, suppliers, and friends; receiving a demonstration on how to use FTS; having a safe or private place to use FTS; and not needing to waste drugs to use FTS.

Of the seven factors, not needing to waste drugs received the highest score (mean: 2.7, SD: 1.3). Respondents also identified having a safe or private place (mean: 2.3, SD: 1.3) and receiving recommendations to use FTS from SSP staff (mean: 2.3, SD: 1.2) as factors that would make them somewhat to quite a bit more likely to use FTS. Recommendations from counselor or doctor received the lowest score (mean: 2.0, SD: 1.2).

In analyses not shown, prior FTS use was associated with increased likelihood of FTS use if recommended by a counselor or doctor (p = 0.011), by a supplier (p = 0.013), or recommended by friends (p < 0.001) relative to respondents without prior FTS use. Respondents reporting DOC-methamphetamines reported increased likelihood of FTS use with recommendations from SSP staff (p < 0.001), suppliers (p < 0.001), and friends (p = 0.001) relative to other DOC. Respondents reporting injection use reported increased likelihood of using FTS if recommended by suppliers (p = 0.02) or friends (p = 0.05) relative to respondents reporting non-injection use. Other individual level characteristics were not significantly associated with psychosocial factors.


In a sample of SSP clients in southern WI, individuals who use FTS more often report DOC-heroin, polysubstance use, injection drug use, and recent methadone treatment compared with individuals who do not use FTS. As such, FTS use might be more common among people with severe addiction and/or at higher risk of overdose [34,35,36].

We also identified populations not yet using FTS. Individuals who use FTS were less likely to report DOC-opioid analgesics, and rates of testing opioid analgesics were quite low among individuals with regular opioid analgesic use. Rates of stimulant testing were also low among respondents with regular stimulant use, particularly for methamphetamine. Yet, respondents reported a high level of fentanyl penetration consistent with state overdose mortality data [37]. These findings align with recent evidence that a high proportion of co-involved stimulant-opioid overdose occurs among individuals not intending to use opioids [38]. Rising rates of fentanyl adulteration and co-involved stimulant-opioid overdose [38, 39] call for increased educational outreach about the risks of fentanyl in nonopioid substances [39, 40] and wider access to robust drug checking services [41, 42].

We observed disparities in FTS use by race and ethnicity, with non-Hispanic whites more likely to use FTS than non-Hispanic Blacks, Hispanics, or non-Hispanic other or multiple races. These findings reinforce literature documenting racial disparities in receipt of harm reduction services [43,44,45]. Given the disproportionate growth in opioid-involved overdose among Black and Latinx PWUD [46, 47], it is critical that public health and harm reduction agencies expand efforts to ensure equitable access to FTS supplies and education.

We found that a large set of situational, logistical and psychosocial factors influence FTS use. For example, respondents reported that suppliers’ advisement about a new batch or potency prompt FTS use. Respondents also reported that transportation and additional distribution sites (e.g., pharmacy or health department) impact FTS use alongside mobile delivery services. These findings recommend multiple approaches to reducing geographic barriers. Poignantly, respondents reported that having a safe or private place to use promotes FTS use, which aligns with recent qualitative work [25] and supports the role of overdose prevention sites in reducing overdose risk [48,49,50]. Finally, SSP staff recommendations may impact FTS use more than recommendations from counselors and doctors, though these findings may reflect limited access to health care [51], as evidenced by low rates of recent treatment or counseling.

Several findings carry safety implications. First, almost two-thirds of FTS users report FTS use some of the time or less. However, FTS results on a single dose cannot assess the entire source. As a result, the ability of FTS to identify fentanyl requires testing the entire drug source or testing with each use. Our findings recommend interventions that support more frequent FTS use.

Second, we found that 13% of respondents who use FTS report testing after drug use. While post-consumption drug checking can inform future use, pre-consumption drug checking has greater potential to impact overdose risk. Thus, intentionally discussing the timing of FTS use could be an important opportunity to increase the impact of FTS on overdose risk.

Third, we found that almost 30% of respondents reported confusion about prior test results, matching other studies [25]. While we did not confirm education receipt with each respondent, the SSP from which we recruited participants provides one-on-one education (in addition to printed materials) from harm reduction specialists about a variety of topics including how to use and interpret FTS. The educational material included in the FTS kit is standard across the SSP locations included in this study. Given this context, persistent confusion about test interpretation calls for additional research with PWUD to identify effective interventions. In addition, 60% reported using FTS to look for fentanyl analogs. However, while FTS can detect a large number of analogs, it is possible for an FTS test to produce false negatives [52, 53]. As such, a negative test result cannot guarantee the absence of analogs. Confusion and misunderstanding when interpreting FTS results could increase overdose risk and indicates a clear role for more robust drug checking services [41, 42] and additional research exploring FTS analog detection in real world samples.

Finally, we found that 70% of respondents report trying to find drugs that contain fentanyl. Given these findings, it is important that providers and educators emphasize harm reduction techniques that acknowledge the likelihood of fentanyl use, such as possessing multiple doses of naloxone (overdose antidote) and not using alone.

Several study findings inform efforts to expand FTS use. First, relative to non-FTS users, FTS users reported a greater likelihood of increasing FTS use with recommendations from health care providers, suppliers, or peers. Thus, these strategies may not be as effective to encourage initial FTS use. Second, we found that concern related to wasting drugs influenced the likelihood of using FTS. Correcting this misperception among PWUD could help expand use of FTS. Third, FTS use was associated with SSP site, with greater FTS use in more urban locations. This variation may reflect differences in transportation barriers, which respondents identified as important factors impacting FTS use. Increasing geographic availability of FTS across diverse locations might help overcome these challenges.

This analysis involved several limitations. First, our sample only included SSP clients. As a result, our findings may reflect the perspective of individuals interested in harm reduction services. Second, our sample is limited to southern Wisconsin, which is more urban than the northern half of the state. Third, to ensure the privacy and protection of respondents, we collected no identifying data. As a result, we could not ensure that respondents did not participate multiple times or in both study phases.


In sum, we find that SSP clients who use FTS are more often non-Hispanic white, report DOC-heroin and seek fentanyl relative to those who do not use FTS. Frequent positive test results confirm a high level of fentanyl penetration in the southern Wisconsin drug market. While the rate of FTS use to check heroin is high, the rate of FTS use to check illicit stimulants remains low even among individuals with regular stimulant use. Factors that prompt FTS use include supplier reports of a new batch or increased potency and recommendations to use FTS by SSP staff, among others. To expand FTS use, our findings suggest (a) focusing on populations less inclined to use FTS (those reporting DOC-opioid analgesics or a non-opioid, and PWUD who are Black, Hispanic and other nonwhite races and ethnicities); (b) increasing the number and diversity of FTS distribution locations; and (c) correcting misperceptions about wasting drugs when using FTS. Notably, in the course of delivering FTS education, providers should highlight the importance of pre-consumption testing, anticipatory guidance in the setting of confusing results, and limitations of FTS regarding fentanyl analogs. Finally, given the high proportion of PWUD seeking fentanyl, health care providers and harm reduction staff should not assume that FTS will promote fentanyl avoidance. In particular, counseling should emphasize additional behaviors and harm reduction techniques (e.g., naloxone use and not using alone) that PWUD can employ to mitigate risk of overdose when using drugs that test positive for fentanyl.

Availability of data and materials

The datasets generated and analyzed during the current study are not publicly available at the time of publication.



Fentanyl test strips


People who use drugs


Syringe service program


University of Wisconsin School of Medicine and Public Health


Drug of choice


  1. Rudd R, Seth P, David F, Scholl L. Increases in drug and opioid-involved overdose deaths—United States, 2010–2015. MMWR Morb Mortal Wkly Rep. 2016;65(50–51):1445–52.

    Article  Google Scholar 

  2. Mattson CL, Tanz LJ, Quinn K, Kariisa M, Patel P, Davis NL. Trends and geographic patterns in drug and synthetic opioid overdose deaths—United States, 2013–2019. Morb Mortal Wkly Rep. 2021;70(6):202.

    Article  Google Scholar 

  3. National Institute on Drug Abuse. Overdose death rates. [cited 2020 Mar 27]. Available from:

  4. Ciccarone D. The triple wave epidemic: supply and demand drivers of the US opioid overdose crisis. Int J Drug Policy. 2019;71:183.

    Article  Google Scholar 

  5. Larochelle MR, Bernson D, Land T, Stopka TJ, Wang N, Xuan Z, et al. Medication for opioid use disorder after nonfatal opioid overdose and association with mortality: a cohort study. Ann Intern Med. 2018;169(3):137–45.

    Article  Google Scholar 

  6. Sordo L, Barrio G, Bravo MJ, Indave BI, Degenhardt L, Wiessing L, et al. Mortality risk during and after opioid substitution treatment: systematic review and meta-analysis of cohort studies. BMJ. 2017;357:j1550.

    Article  Google Scholar 

  7. Saini J, Johnson B, Qato DM. Self-reported treatment need and barriers to care for adults with opioid use disorder: the US national survey on drug use and health, 2015 to 2019. Am J Public Health. 2022;112(2):284–95.

    Article  Google Scholar 

  8. Substance Abuse and Mental Health Services Administration (SAMHSA). Key substance use and mental health indicators in the United States: results from the 2018 national survey on drug use and health. 2019 [cited 2022 Aug 29]; Available from:

  9. Peiper NC, Clarke SD, Vincent LB, Ciccarone D, Kral AH, Zibbell JE. Fentanyl test strips as an opioid overdose prevention strategy: findings from a syringe services program in the Southeastern United States. Int J Drug Policy. 2019;63:122–8.

    Article  Google Scholar 

  10. Sherman SG, Park JN, Glick J, McKenzie M, Morales K, Christensen T, et al. FORECAST study summary report. Johns Hopkins Bloomberg School of Public Health; 2018. Available from:

  11. Goldman JE, Waye KM, Periera KA, Krieger MS, Yedinak JL, Marshall BD. Perspectives on rapid fentanyl test strips as a harm reduction practice among young adults who use drugs: a qualitative study. Harm Reduct J. 2019;16(1):1–11.

    Article  Google Scholar 

  12. Krieger MS, Goedel WC, Buxton JA, Lysyshyn M, Bernstein E, Sherman SG, et al. Use of rapid fentanyl test strips among young adults who use drugs. Int J Drug Policy. 2018;61:52–8.

    Article  Google Scholar 

  13. Krieger MS, Yedinak JL, Buxton JA, Lysyshyn M, Bernstein E, Rich JD, et al. High willingness to use rapid fentanyl test strips among young adults who use drugs. Harm Reduct J. 2018;15(1):1–9.

    Article  Google Scholar 

  14. Marshall K. Fentanyl test strip pilot. Harm reduction coalition; 2018 Feb [cited 2020 Jan 28]. Available from:

  15. Karamouzian M, Dohoo C, Forsting S, McNeil R, Kerr T, Lysyshyn M. Evaluation of a fentanyl drug checking service for clients of a supervised injection facility, Vancouver, Canada. Harm Reduct J. 2018;15(1):1–8.

    Article  Google Scholar 

  16. Weicker NP, Owczarzak J, Urquhart G, Park JN, Rouhani S, Ling R, et al. Agency in the fentanyl era: exploring the utility of fentanyl test strips in an opaque drug market. Int J Drug Policy. 2020;84:102900.

    Article  Google Scholar 

  17. Davis CS, Lieberman AJ, O’Kelley-Bangsbergn M. Legality of drug checking equipment in the United States: a systematic legal analysis. Drug Alcohol Depend. 2022;234:109425.

    Article  Google Scholar 

  18. Davis CS, Carr DH, Samuels EA. Paraphernalia laws, criminalizing possession and distribution of items used to consume illicit drugs, and injection-related harm. Am J Public Health. 2019;109(11):1564–7.

    Article  Google Scholar 

  19. Olsen Y, Sharfstein JM. Confronting the stigma of opioid use disorder—and its treatment. JAMA. 2014;311(14):1393–4.

    Article  Google Scholar 

  20. Wallace B, van Roode T, Pagan F, Phillips P, Wagner H, Calder S, et al. What is needed for implementing drug checking services in the context of the overdose crisis? A qualitative study to explore perspectives of potential service users. Harm Reduct J. 2020;17(1):1–14.

    Article  Google Scholar 

  21. Priester MA, Browne T, Iachini A, Clone S, DeHart D, Seay KD. Treatment access barriers and disparities among individuals with co-occurring mental health and substance use disorders: an integrative literature review. J Subst Abuse Treat. 2016;61:47–59.

    Article  Google Scholar 

  22. Whetten R, Whetten K, Pence BW, Reif S, Conover C, Bouis S. Does distance affect utilization of substance abuse and mental health services in the presence of transportation services? AIDS Care. 2006;18(sup1):27–34.

    Article  Google Scholar 

  23. Friedmann PD, Lemon SC, Stein MD. Transportation and retention in outpatient drug abuse treatment programs. J Subst Abuse Treat. 2001;21(2):97–103.

    Article  CAS  Google Scholar 

  24. Phillips M, DeBeck K, Desjarlais T, Morrison T, Feng C, Kerr T, et al. Inability to access addiction treatment among street-involved youth in a Canadian setting. Subst Use Misuse. 2014;49(10):1233–40.

    Article  Google Scholar 

  25. Reed MK, Salcedo VJ, Guth A, Rising KL. “If I had them, I would use them every time”: perspectives on fentanyl test strip use from people who use drugs. J Subst Abuse Treat. 2022;140:108790.

    Article  CAS  Google Scholar 

  26. Reed MK, Guth A, Salcedo VJ, Hom JK, Rising KL. “You can’t go wrong being safe”: motivations, patterns, and context surrounding use of fentanyl test strips for heroin and other drugs. Int J Drug Policy. 2022;103:103643.

    Article  Google Scholar 

  27. Dasgupta N, Figgatt MC. Invited commentary: drug checking for novel insights into the unregulated drug supply. Am J Epidemiol. 2022;191(2):248–52.

    Article  Google Scholar 

  28. Hsieh HF, Shannon SE. Three approaches to qualitative content analysis. Qual Health Res. 2005;15(9):1277–88.

    Article  Google Scholar 

  29. Weller S, Romney A. Defining a domain and free listing. In: Systematic Data collection (Qualitative research methods; vol. 10). Newbury Park: Sage Publications Inc; 1988.

  30. Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, Conde JG. Research electronic data capture (REDCap)—a metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform. 2009;42(2):377–81.

    Article  Google Scholar 

  31. Harris PA, Taylor R, Minor BL, Elliott V, Fernandez M, O’Neal L, et al. The REDCap consortium: building an international community of software platform partners. J Biomed Inform. 2019;95:103208.

    Article  Google Scholar 

  32. Wisconsin Network for Research Support. CARDS [Internet]. [cited 2022 Mar 4]. Available from:

  33. 2010 Rural-Urban Commuting Area (RUCA) Codes [Internet]. 2020 Aug [cited 2022 Feb 24]. Available from:

  34. Lyons RM, Yule AM, Schiff D, Bagley SM, Wilens TE. Risk factors for drug overdose in young people: a systematic review of the literature. J Child Adolesc Psychopharmacol. 2019;29(7):487–97.

    Article  Google Scholar 

  35. Coffin PO, Galea S, Ahern J, Leon AC, Vlahov D, Tardiff K. Opiates, cocaine and alcohol combinations in accidental drug overdose deaths in New York City, 1990–98. Addiction. 2003;98(6):739–47.

    Article  Google Scholar 

  36. Martins SS, Sampson L, Cerdá M, Galea S. Worldwide prevalence and trends in unintentional drug overdose: a systematic review of the literature. Am J Public Health. 2015;105(11):e29-49.

    Article  Google Scholar 

  37. Wisconsin Department of Health Services. Dose of reality: opioid deaths by county dashboard. 2022 Feb [cited 2022 Aug 12]. Available from:

  38. Coffin PO, McMahan VM, Murphy C. Evidence of pre-mortem opioid use among fentanyl overdose decedents in a safety net healthcare system. J Urban Health. 2022;99:1–8.

    Article  Google Scholar 

  39. Korthuis PT, Cook RR, Foot CA, Leichtling G, Tsui JI, Stopka TJ, et al. Association of methamphetamine and opioid use with nonfatal overdose in rural communities. JAMA Netw Open. 2022;5(8):e2226544–e2226544.

    Article  Google Scholar 

  40. Gladden RM, O’Donnell J, Mattson CL, Seth P. Changes in opioid-involved overdose deaths by opioid type and presence of benzodiazepines, cocaine, and methamphetamine—25 states, July–December 2017 to January–June 2018. Morb Mortal Wkly Rep. 2019;68(34):737.

    Article  Google Scholar 

  41. Karch L, Tobias S, Schmidt C, Doe-Simkins M, Carter N, Salisbury-Afshar E, et al. Results from a mobile drug checking pilot program using three technologies in Chicago, IL, USA. Drug Alcohol Depend. 2021;228:108976.

    Article  Google Scholar 

  42. Carroll JJ, Mackin S, Schmidt C, McKenzie M, Green TC. The Bronze age of drug checking: barriers and facilitators to implementing advanced drug checking amidst police violence and COVID-19. Harm Reduct J. 2022;19(1):1–13.

    Article  Google Scholar 

  43. Dayton L, Tobin K, Falade-Nwulia O, Davey-Rothwell M, Al-Tayyib A, Saleem H, et al. Racial disparities in overdose prevention among people who inject drugs. J Urban Health. 2020;97(6):823–30.

    Article  Google Scholar 

  44. Rowe C, Santos GM, Vittinghoff E, Wheeler E, Davidson P, Coffin PO. Predictors of participant engagement and naloxone utilization in a community-based naloxone distribution program. Addiction. 2015;110(8):1301–10.

    Article  Google Scholar 

  45. Lopez AM, Thomann M, Dhatt Z, Ferrera J, Al-Nassir M, Ambrose M, et al. Understanding racial inequities in the implementation of harm reduction initiatives. Am J Public Health. 2022;112(S2):S173–81.

    Article  Google Scholar 

  46. Furr-Holden D, Milam AJ, Wang L, Sadler R. African Americans now outpace whites in opioid-involved overdose deaths: a comparison of temporal trends from 1999 to 2018. Addiction. 2021;116(3):677–83.

    Article  Google Scholar 

  47. Lippold KM, Jones CM, Olsen EO, Giroir BP. Racial/ethnic and age group differences in opioid and synthetic opioid–involved overdose deaths among adults aged≥ 18 years in metropolitan areas—United States, 2015–2017. Morb Mortal Wkly Rep. 2019;68(43):967.

    Article  Google Scholar 

  48. Wallace B, Pagan F, Pauly BB. The implementation of overdose prevention sites as a novel and nimble response during an illegal drug overdose public health emergency. Int J Drug Policy. 2019;66:64–72.

    Article  Google Scholar 

  49. Pauly B, Wallace B, Pagan F, Phillips J, Wilson M, Hobbs H, et al. Impact of overdose prevention sites during a public health emergency in Victoria, Canada. PLoS ONE. 2020;15(5):e0229208.

    Article  CAS  Google Scholar 

  50. Potier C, Laprévote V, Dubois-Arber F, Cottencin O, Rolland B. Supervised injection services: What has been demonstrated? A systematic literature review. Drug Alcohol Depend. 2014;145:48–68.

    Article  Google Scholar 

  51. Wu LT, Zhu H, Swartz MS. Treatment utilization among persons with opioid use disorder in the United States. Drug Alcohol Depend. 2016;169:117–27.

    Article  Google Scholar 

  52. Green TC, Park JN, Gilbert M, McKenzie M, Struth E, Lucas R, et al. An assessment of the limits of detection, sensitivity and specificity of three devices for public health-based drug checking of fentanyl in street-acquired samples. Int J Drug Policy. 2020;77:102661.

    Article  Google Scholar 

  53. Bergh MSS, Øiestad ÅML, Baumann MH, Bogen IL. Selectivity and sensitivity of urine fentanyl test strips to detect fentanyl analogues in illicit drugs. Int J Drug Policy. 2021;90:103065.

    Article  Google Scholar 

Download references


We would like to acknowledge the contributions of the following groups and individuals: Vivent Health, including Kristen Grimes, MAOM and the staff at each study site; the Community Advisors on Research Design and Strategies (CARDS) along with Betty Kaiser and Kat Phelps from the Wisconsin Network for Research Support; and Barbara Bowers, PhD, RN, FAAN from the School of Nursing, University of Wisconsin-Madison.


Funding for this research came from the Department of Family Medicine and Community Health at the University of Wisconsin School of Medicine and Public Health. The funding body was not involved in the study design, data collection, analysis, data interpretation or writing of this manuscript.

Author information

Authors and Affiliations



AT was involved in all stages of the research including study design; implementation; data collection, analysis, and interpretation; and writing of the manuscript. JB was involved in data analysis and interpretation. AB was involved in data collection, analysis of Phase 1, interpretation of findings and editing of the final manuscript. JM was involved in data collection, interpretation of findings and editing of the final manuscript. ESA was involved in data interpretation, analytic design, and editing of the final manuscript. GC was involved in analytic design and data interpretation. RB was involved in study design, implementation, data analysis, interpretation of findings and editing of the final manuscript. All authors reviewed and approved the final manuscript.

Corresponding author

Correspondence to Alyssa Shell Tilhou.

Ethics declarations

Ethics approval and consent to participate

The study protocol was approved by the Institutional Review Board at the University of Wisconsin School of Medicine and Public Health. All respondents provided informed consent prior to participation in both study phases.

Consent for publication

Not applicable.

Competing interests

The authors declare that they have no competing interests.

Additional information

Publisher's Note

Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit The Creative Commons Public Domain Dedication waiver ( applies to the data made available in this article, unless otherwise stated in a credit line to the data.

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Tilhou, A.S., Birstler, J., Baltes, A. et al. Characteristics and context of fentanyl test strip use among syringe service clients in southern Wisconsin. Harm Reduct J 19, 142 (2022).

Download citation

  • Received:

  • Accepted:

  • Published:

  • DOI:


  • Fentanyl test strip (FTS)
  • Opioid
  • Harm reduction
  • Drug testing
  • Overdose