High concentrations of illicit stimulants and cutting agents cause false positives on fentanyl test strips

Abstract Background The opioid epidemic has caused an increase in overdose deaths which can be attributed to fentanyl combined with various illicit substances. Drug checking programs have been started by many harm reduction groups provide tools for users determine the composition of their street drugs. Immunoassay test strips (FTS) allow drugs either filling a baggie or cooker water dissolve sample and test. antibody used FTS is very selective at high dilutions, characteristic traditional use urine testing. These preparation methods lead mg/mL concentrations several potential interferents. We tested whether these concentrated samples could cause false positive results on FTS. Methods 20 ng/mL Rapid Response were obtained from BTNX Inc. against 4 different pharmaceuticals (diphenhydramine, alprazolam, gabapentin, naloxone buprenorphine) 3 stimulants [cocaine HCl, methamphetamine, 3,4-methylenedioxymethamphetamine (MDMA)] 0.2 mg/mL. testing pad divided into 2 sections: control area area. Control signal intensities quantified ImageJ photographs compared threshold set limit detection. Results False indicating presence MDMA, diphenhydramine above 1 Diphenhydramine common cutting agent heroin. protocols suggested online resources would produce such materials. Street need diluted more significantly avoid interference agents stimulants. Conclusions Fentanyl are commercially available, successful detecting specified detection valuable tool efforts. Users should aware that when adulterants concentrations, give result.