The Evidence Base for Fentanyl Test Strips

Sherman et al. (2021), published in Addictive Behaviors, extended the evidence base to a highly vulnerable population: female sex workers (FSW) who use opioids in Baltimore City. This pilot study enrolled 103 participants between April 2018 and February 2019, providing each with five FTS, training, tailored harm reduction messaging, and a naloxone kit at baseline, with a survey administered after one month. Among the 68 participants who completed follow-up, FTS acceptability was exceptionally high: 84% used at least one strip to test their drugs.

A critical gap in the FTS literature has been the absence of population-level evidence connecting FTS availability to mortality outcomes. Bhai, McMichael, and Mitchell (2025), published in Medical Care Research and Review, addressed this gap using a difference-in-differences approach with state-level data from 2018 to 2022. The study exploited the staggered expansion of FTS access across U.S. states as a natural experiment, employing two-way fixed effects models and triple differences specifications to isolate the effect of FTS availability from confounding factors.

The most thorough evidence synthesis to date is the scoping review by Mukherjee et al. (2024), published in the Journal of Addiction Medicine. This review systematically analyzed 91 articles on FTS for harm reduction, covering publications predominantly from North America, all conducted after 2016. The review\\

FTS have received endorsement from multiple authoritative federal bodies, providing grant writers with strong institutional backing to cite. The CDC describes FTS as a low-cost harm reduction tool that can be used to prevent overdoses in combination with other strategies, and recommends expanding community-based drug checking as part of its overdose prevention framework. In April 2021, SAMHSA and the CDC jointly announced that federal grant funding could be used to purchase FTS, a policy change that applied to all federal grant programs where the purchase is consistent with the program\\

Across the published literature, a consistent pattern of behavior change emerges when people receive FTS results. The specific risk-reduction behaviors documented include: using a smaller amount of the drug (reported by 40-45% of those with positive results across studies), proceeding more slowly or doing a tester shot first (reported by 25-42%), using drugs in the presence of another person rather than alone (reported by 39-69%), keeping naloxone nearby (reported frequently in the JAMA 2025 cohort), discarding the drug supply entirely (reported in Goldman 2019 and qualitative studies), and distributing test strips to peers perceived as high-risk. A qualitative study by Peiper et al. (2022) titled \\

For grant writers and policy advocates, the FTS evidence base supports several specific claims that funders and legislators commonly require. When asserting behavior change: cite Peiper et al. (2019) for the five-fold increase in behavior change odds, Krieger et al. (2018) for the 45% reduction in amount used, and Sherman et al.

Several critical research gaps remain, and awareness of these gaps is important for both honest advocacy and for organizations seeking research-oriented funding. First, no completed randomized controlled trial has evaluated FTS, though at least two large-scale RCTs are in progress: one enrolling 2,400 participants across rural and urban counties, and another theory-based trial combining fentanyl overdose education with FTS distribution. Results from these trials, expected in the coming years, will substantially strengthen the evidence base. Second, formal cost-effectiveness analyses specific to FTS distribution programs remain absent from the literature, despite the low unit cost of strips and the high economic burden of overdose deaths.

The evidence base for fentanyl test strips is strong in several domains and actively growing in others. FTS have demonstrated high analytical sensitivity (98.5%) for detecting fentanyl and its analogs, consistently high acceptability and uptake rates (77-84%) across diverse populations, and reliable associations with meaningful behavior changes including reduced drug quantities, slower consumption, decreased solitary use, and increased naloxone availability. Population-level evidence now links expanded FTS access to a 7% reduction in overdose mortality, with an even larger effect among Black communities. Federal agencies including the CDC, SAMHSA, and the National Academies of Sciences have endorsed FTS distribution, and federal funding is explicitly available for their purchase.