Xylazine-Fentanyl Positivity and Concentration in Urine Drug Tests

How are the presence and concentration of xylazine with fentanyl changing in the US over time and region in the current phase of the opioid crisis?This cross-sectional study analyzed 42 307 fentanyl-positive urine drug testing (UDT) samples collected between March 2023 and September 2025 that were also tested for xylazine. In the East and West US, xylazine detection increased while concentration in UDT samples sharply decreased.This cross-sectional study found that the concentration of xylazine in the US drug supply may be decreasing, but xylazine with fentanyl was still present and spreading.

Corresponding Author: Olivia K. Sugarman, PhD, MPH, Department of Health Policy and Management, Johns Hopkins Bloomberg School of Public Health, 1812 Ashland Ave, Room 375, Baltimore, MD 21205 (osugarm1@jh.edu).

Link to the article in your story

We encourage you to link out to this article in your story using the link below. It includes an access token that will give free access to the article for your readers up to one year after publication. (The link will be live after the article publishes and embargo is lifted.)

Please see the article for additional information, including full author list, author contributions and affiliations, conflict of interest and financial disclosures, and funding and support.

Need more information? Contact us.