Effect of environmental conditions on the performance of fentanyl field detection tests

Illicit fentanyl is a well known contributor to the ongoing opioid crisis. The ability to take either protective action or administer medical countermeasures can be predicated on the ability to detect even minute concentrations. For this reason, a fast, accurate, and cost effective method for fentanyl detection in the field is necessary. State of the art methods tend to be large and expensive powered electronics that limit their wide dissemination. Alternative methods of detection include laminar flow immunoassays (LFIs) and colorimetric indicators. Many of these tests have been evaluated for potential field use under laboratory conditions. However, none of these studies have evaluated them under environmentally relevant conditions, mainly temperature and humidity, that may be encountered in the field. These environmental conditions may affect the limits of detection or cross reactivity of the test, and ultimately the user’s interpretation of and response to the result. Here we assess the effect of five environmental conditions on the responses of two LFI tests and one colorimetric test to six fentanyl analogues and five cross reactivity standards.