Fentanyl test strips. At home testing kit. Includes easy to read instructions, measurement spoon, water measurement pouch. Dosetest fentanyl test strips are the most sensitive and accessible method for checking if your substance contains fentanyl. Approved by 3rd party lab testing, these fentanyl test strips react to more than 20 different variants of fentanyl. Our strips were tested using 74 different substance samples, including both analytical standards and street samples, to provide the most realistic consumer scenarios.