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

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

Bis(N,N-diethyl-4-methyl-4-piperazine-1-carboxamide) tetra-kis-(iso-thio-cyanato-κN)-cobalt(II), a model compound for the blue color developed in the Scott test.

The complex, bis-(N,N-diethyl-4-methyl-4-piperazine-1-carboxamide) tetra-kis(iso-thio-cyanato-κN)cobalt(II) (N,N-diethyl-4-methyl-4-piperazine-1-carboxamide = di-ethyl-carbamazine), (C10H22N3O)2[Co(NCS)4], is presented. This com-plex is a blue precipitate, insoluble in water but soluble in organic solvents, that is formed from the reaction of diethylcarbamazine citrate, a protonated tertiary amine, with cobalt(II) and thio-cyanate. This reaction, in the form of the Scott test, is a common presumptive test for cocaine hydro-chloride. The known cobalt compound, [K2Co(NCS)4]·3H2O, has a deep-blue coloration due to the tetra-hedral [Co(NCS)4]2- that is also present in the ion pair with bulky amines, and is similar to the color of other tetra-hedral cobalt(II) complex ions, such as [CoCl4]2-. The structure is consistent with a previous proposal that a hydro-phobic ion pair formed between [Co(NCS)4]2- and two protonated mol-ecules of cocaine is responsible for the blue hydro-phobic products formed by cocaine in the Scott test.

Community overdose surveillance: Comparing substances collected from the death scene investigation to toxicology results.

BACKGROUND: Recent overdose trends are characterized by increased toxicological detection of stimulants with opioids, yet it is unclear whether these substances are mixed prior to consumption or purposefully used simultaneously. METHODS: Postmortem toxicology data were collected in Marion County, Indiana, from 45 fatal overdose cases involving heroin, fentanyl, methamphetamine, or cocaine. Substances found by death scene investigators at the scene of the fatal overdose (57 samples) were tested using high-pressure liquid chromatography mass-spectrometry (LC-MS) technology. We compared toxicology and LC-MS results to understand whether substances contributing to overdose were found in combination or separately at the scene of the overdose. RESULTS: Comparing toxicology reports with LC-MS results from substances found at the scene of overdose deaths involving opioids and stimulants reveal that deaths are largely the result of the co-use of opioids and stimulants, rather than use of stimulants combined with opioids. CONCLUSIONS: Collecting and testing physical samples from fatal overdose scenes and comparing these to post-mortem toxicology results is a new way to examine polydrug use patterns. This community overdose surveillance method can be used to improve overdose prevention and response efforts.

idPAD: Paper Analytical Device for Presumptive Identification of Illicit Drugs.

As drug overdose deaths across the United States continue to rise, there is increasing interest in field testing of illicit substances. This work discusses a paper-based analytical device (idPAD) that can run a library of 12 colorimetric tests at the same time, each detecting different chemical functional groups and materials found in illicit drugs, distractor substances, and cutting agents. The idPAD requires no electricity, costs less than $2 USD, and requires minimal training to operate. The results of the 12 tests form a color barcode which is "read" by comparison to standard images. The accuracy of the idPAD was assessed using samples of heroin, cocaine HCl, crack, and methamphetamine at concentrations of 25%-100% in a lactose matrix, as well as pure lactose. Based on 840 "reads" by three different users, the idPAD showed 95% sensitivity and 100% specificity for detecting these drugs; the most common error was mistaking cocaine HCl for crack or crack for cocaine HCl. In a second step, samples of heroin, cocaine, and methamphetamine (n = 30) and distractor substances (pharmaceuticals, cutting agents, and other illicit drugs, n = 64) were tested by two readers, yielding a sensitivity of 100% and specificity of 97%. Targeted substances were detected reliably at 55-180 µg/lane, and the idPAD was found to be stable for at least 3 months when stored at room temperature. The library approach used in the idPAD may provide the accuracy and robustness necessary for a presumptive field drug test.