Recherche de stupéfiant par bandelettes urinaires - suspicion de réaction croisée entre fentanyl et fenspiride

In order to remove the doubt, we used a method by liquid chromatography with mass spectrometry high-resolution detection (LCMS-HR) available in the laboratory of toxicology which affirmed the absence of fentanyl and showed the presence of fenspiride. The patient subsequently confirmed being treated for a few days by Pneumorel®. It is therefore advisable to remain vigilant with the urine drug testing and the potential risk false positive undocumented.