Assessing the limit of detection of Fourier‐transform infrared spectroscopy and immunoassay strips for fentanyl in a real‐world setting

Abstract

Introduction and AimsDrug checking is a harm reduction intervention increasingly used in the context of the opioid overdose epidemic. The aim of the study was to determine the limit of detection for fentanyl of two point‐of‐care drug checking technologies.Design and MethodsSamples tested at point‐of‐care using Bruker Fourier transform infrared (FTIR) spectroscopy and BTNX fentanyl immunoassay strips were sent for confirmatory laboratory analysis using quantitative nuclear magnetic resonance (qNMR) spectroscopy. Concentrations by weight were determined and compared to results obtained with point‐of‐care methods.ResultsIn total, 283 samples were sent for qNMR analysis; among these, 173 (61.1%) tested positive for fentanyl. As determined by qNMR, fentanyl concentration by weight ranged from 1% to 91%. Among these 173 samples, fentanyl was not detected in 30 (17.3%) samples by FTIR and in 4 (2.3%) samples by test strip. Samples containing fentanyl that went undetected by FTIR had concentrations ≤10%. The four samples containing fentanyl that went undetected by test strip had concentrations ≤5% (i.e. 1%, 3%, 4%, 5%).Discussion and ConclusionsFentanyl immunoassay strips were able to consistently detect the presence of fentanyl in samples at lower concentrations than FTIR spectroscopy. Given that FTIR spectroscopy is able to quantify content, mixture and concentrations on an array of compounds beyond just fentanyl but requires concentrations generally greater than 10%, these findings provide evidence for use of FTIR spectroscopy and immunoassay strips in combination to compensate for the limitations of each technology alone.

Implementing an integrated multi‐technology platform for drug checking: Social, scientific, and technological considerations

“…The crystal is cleaned with isopropanol and a new baseline is collected prior to each sample measurement. Although the limit of detection (LOD) for specific components in a drug mixture is difficult to assess due to the variety of cutting agents present, moisture content of the sample, and scattering effects due to power particle size, studies have estimated the LOD for fentanyl using IR spectroscopy to be in the range 1%–5% by weight 31,33 …”

“…In Toronto, Canada, drug checking is being piloted within several supervised injection sites with samples tested using fentanyl immunoassay test strips onsite and testing samples offsite using LC‐ and GCMS techniques 32 . Also in Canada, the British Columbia Centre on Substance Use is piloting point‐of‐contact drug checking at multiple supervised injection sites and overdose prevention sites using a Fourier transform infrared spectroscopy with test strips 27,33 …”

“…32 Also in Canada, the British Columbia Centre on Substance Use is piloting point-of-contact drug checking at multiple supervised injection sites and overdose prevention sites using a Fourier transform infrared spectroscopy with test strips. 27,33 As elsewhere, in Canada, drug checking as a harm reduction practice is imbedded within the nightlife and electronic dance festival movements including over 16 years of grassroots drug checking at the Shambhala Festival by ANKORS and volunteers. 34 The emergence of the fentanyl related overdose crisis has led to Health Canada funding several pilot projects to explore the potential role of drug checking within the overdose response strategy.…”

Rapid and quantitative determination of fentanyls and pharmaceuticals from powdered drug samples by paper spray mass spectrometry

“…These systems have modest power requirements, are relatively low cost, and have rapid analysis times. An assessment of FTIR spectroscopy and immunoassay test strips for the analysis of fentanyl in real street drug samples found that of 173 samples that tested positive for fentanyl (using quantitative nuclear magnetic resonance), 30 (17.3%) failed to detect fentanyl using FTIR spectroscopy, and four (2.3%) did not detect fentanyl using immunoassay test strips 8 . FTIR was able to quantify drug and excipient content, but required concentrations ≥10% w/w, and even the immunoassay test strips required fentanyl concentrations ≥5% w/w for reliable detection.…”

High Concentrations of Illicit Stimulants and Cutting Agents Cause False Positives on Fentanyl Test Strips

“…(15,16) In order to help prevent overdoses, lateral ow immunoassay test strips originally designed for monitoring traces of fentanyl and its analogs in urine are being explored as a drug checking technology in harm reduction contexts. (17)(18)(19)(20) One commonly used fentanyl test strip or "FTS" (BTNX Inc., Markham, ON, Canada) is a lateral ow chromatographic immunoassay for the qualitative detection of fentanyl in urine at the cutoff concentration of 20 ng/ml. A positive result on this test strip gives one line, a negative result gives two lines, and an invalid test gives either no line or no control line.…”