# What’s in the Powder? Evaluating Fentanyl Test Strip Sensitivity to Common Household Items in Chemical Emergency Response Scenarios

## TL;DR

This study tests how well fentanyl test strips work in real-world emergency situations where unknown powders may be mixed with common household substances.

## Contribution

The first evaluation of fentanyl test strip performance in the presence of common diluents during chemical emergency response.

## Key findings

- The experimental limit of detection for fentanyl was 0.05 μg/mL, lower than the reported 0.20 μg/mL.
- Diluents like sugar and flour affected test strip accuracy, requiring higher fentanyl concentrations for a positive result.
- Results near the detection limit were often hard to interpret, posing challenges for first responders.

## Abstract

The increasing prevalence of opioid misuse, particularly
the adulteration
of illicit substances with fentanyl, has heightened the need for effective
field detection methods for unknown powders. First responders, including
chemical emergency response and Hazardous Materials (HazMat) teams,
face significant challenges in assessing chemical threats in real-time
without the resources of a controlled laboratory environment. Immunoassay
test strips are commonly used for drug detection and are considered
potential tools for identifying fentanyl in emergency scenarios. However,
the impact of common diluents (substances such as sugar, flour, and
other commonplace additives) on the accuracy of these test strips
is unexplored. This study evaluates the limit of detection (LOD) of
a popular commercially available fentanyl test strip (FTS) in the
presence of various diluents commonly found in emergency situations.
The experimental LOD was determined to be 0.05 μg/mL, significantly
lower than the reported LOD of 0.20 μg/mL. While no false positives
were observed with diluents alone, the presence of diluents in fentanyl
solutions altered FTS results, requiring higher concentrations of
fentanyl to achieve a positive reading. Results were often difficult
to interpret, particularly near the LOD, which could pose challenges
for first responders in real-world scenarios. This work is the first
to assess the application of FTS to chemical emergency response situations
and threat assessment of unknown powders. Commercially available FTS
are cost-effective, user-friendly, provide rapid results, and detect
low concentrations of fentanyl even in the presence of other substances.