Decreasing fentanyl concentrations in urinalysis results for methadone treatment admissions: Evidence of changing fentanyl exposure in street drugs

Emily Giangrande; James A. Swartz; Emily Giangrande; James A. Swartz

doi:10.3934/publichealth.2026045

AIMS Public Health

2026, Volume 13, Issue 3: 849-863. doi: 10.3934/publichealth.2026045

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Research article

Decreasing fentanyl concentrations in urinalysis results for methadone treatment admissions: Evidence of changing fentanyl exposure in street drugs

Emily Giangrande ^,,
James A. Swartz

Jane Addams College of Social Work, University of Illinois Chicago, Chicago, IL, USA

Received: 14 February 2026 Revised: 12 June 2026 Accepted: 26 June 2026 Published: 07 August 2026

Background
Recent declines in opioid-related overdose fatalities (OROF) in Chicago and nationally in the U.S. have prompted questions about whether changes in fentanyl exposure may be occurring in the illicit opioid supply.
Objective
This study examined temporal trends in fentanyl exposure among individuals entering opioid treatment, using admission urinalysis as a biological indicator of recent opioid exposure.
Methods
We conducted a secondary analysis of clinical admission data collected between 2023 and 2025 from a community-based opioid treatment program (OTP) on Chicago's West Side (N = 339). Multivariable ordinary least squares regression models were used to examine changes in log-transformed urine concentrations of fentanyl, norfentanyl, and morphine across admission years, adjusting for sociodemographic and clinical characteristics. Concentration analyses were restricted to participants with confirmed positive tests.
Results
Relative to 2023, fentanyl concentrations were significantly lower in 2024 (b = −0.77, p < 0.001) and 2025 (b = −1.29, p < 0.001), corresponding to approximately 54% and 72% reductions, respectively. Norfentanyl concentrations also declined over time, while morphine concentrations remained stable. Participant characteristics and the prevalence of opioid detection at admission were largely stable across years.
Conclusions
Declining concentrations of fentanyl and norfentanyl, alongside stable morphine levels, suggest reduced fentanyl exposure among treatment-seeking individuals over the study period. While urinalysis provides an indirect indicator and cannot establish causality, these findings are consistent with broader reports of declining fentanyl-related overdose mortality and highlight the potential value of treatment-entry toxicology data as a sentinel indicator of changes in illicit opioid markets.
- fentanyl,
- opioid overdose,
- urinalysis, methadone,
- opioid treatment program,
- opioids
Citation: Emily Giangrande, James A. Swartz. Decreasing fentanyl concentrations in urinalysis results for methadone treatment admissions: Evidence of changing fentanyl exposure in street drugs[J]. AIMS Public Health, 2026, 13(3): 849-863. doi: 10.3934/publichealth.2026045

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Abstract

Background

Recent declines in opioid-related overdose fatalities (OROF) in Chicago and nationally in the U.S. have prompted questions about whether changes in fentanyl exposure may be occurring in the illicit opioid supply.

Objective

This study examined temporal trends in fentanyl exposure among individuals entering opioid treatment, using admission urinalysis as a biological indicator of recent opioid exposure.

Methods

We conducted a secondary analysis of clinical admission data collected between 2023 and 2025 from a community-based opioid treatment program (OTP) on Chicago's West Side (N = 339). Multivariable ordinary least squares regression models were used to examine changes in log-transformed urine concentrations of fentanyl, norfentanyl, and morphine across admission years, adjusting for sociodemographic and clinical characteristics. Concentration analyses were restricted to participants with confirmed positive tests.

Results

Relative to 2023, fentanyl concentrations were significantly lower in 2024 (b = −0.77, p < 0.001) and 2025 (b = −1.29, p < 0.001), corresponding to approximately 54% and 72% reductions, respectively. Norfentanyl concentrations also declined over time, while morphine concentrations remained stable. Participant characteristics and the prevalence of opioid detection at admission were largely stable across years.

Conclusions

Declining concentrations of fentanyl and norfentanyl, alongside stable morphine levels, suggest reduced fentanyl exposure among treatment-seeking individuals over the study period. While urinalysis provides an indirect indicator and cannot establish causality, these findings are consistent with broader reports of declining fentanyl-related overdose mortality and highlight the potential value of treatment-entry toxicology data as a sentinel indicator of changes in illicit opioid markets.

Acknowledgments

We would like to thank Healthcare Alternative Systems (HAS) for providing access to the data they collect as part of their NEXA methadone program. In particular, we would like to thank Ms. Shreeya Patil, Dr. Karina Bull, and Ms. Nadine Darwish.

Authors' contributions

Emily Giangrande contributed to conceptualization, writing the original draft, and manuscript review and editing. James Swartz contributed to conceptualization, data acquisition (resources), formal analysis, and manuscript review and editing. All authors have read and agreed to the published version of the manuscript.

Conflict of interest

James Swartz is an editorial board member for AIMS Public Health and was not involved in the editorial review or the decision to publish this article. All authors declare that there are no competing interests.

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