The Rapid Response™ Fentanyl Test Strip (Liquid/Powder) is a user-friendly, economical dipstick assay. It is a fast, qualitative screening assay that promptly and accurately identifies fentanyl at cut-off concentrations over 200 ng/mL. This drug test can yield precise findings in as little as one minute. Exclusively for forensic purposes. Not an In Vitro Diagnostic.