Fentanyl Substance Test Tests for the presence of fentanyl in powder substance Safe, easy to use and results within minutes Positive results = The appearance of any red-violet color indicates the presence of fentanyl. Any and all color changes may indicate a presence of a potential harmful substance (such as fentanyl, heroin, morphine, codeine, amphetamine or methamphetamine) All results are presumptive, confirmatory testing should be done by a lab Includes: test(s), instructions, test translation & gloves