
Aiming to determine the presence of heroin, fentanyl, amphetamine-type stimulants (ATS), xylazine, and other substances in Tijuana and Mexicali, Baja California, researchers randomly selected 300 drug residues from confiscated syringe plungers. After analyzing them with gas chromatography–mass spectrometry (GC–MS) and BTNX test strips for ATS and fentanyl and its analogs, the test strips showed a high positive predictive value of 81% when compared with GC–MS.





























