Feasibility Study of Using Mobile Phone-Based Experience Sampling to Assess Drug Checking by Opioid Street Drug Users

Abstract

Background: To date, evaluations of take-home fentanyl (and/or benzodiazepine) test strip use – the most common form of drug checking services – and potential effects on overdose risk have relied on retrospective accounts for some preceding time period, usually a week to several months. Such accounts, however, are subject to recall and memory biases. This pilot study assessed the feasibility of using experiential sampling to collect daily information in situ on drug checking and associated overdose risk reduction – the primary outcomes - among a sample of street opioid users and compared the results to retrospective reports. Methods: We recruited 12 participants from a Chicago-based syringe services program. Participants were 18 years of age or older, reported using opioids purchased on the street 3+ times per week in the past month, and had an available Android mobile phone. A phone-based app was programmed to collect daily drug checking information and provided to each participant along with a supply of fentanyl and benzodiazepine test strips and instructions for use over 21 days. Comparable retrospective data were collected via follow-up in-person surveys at the conclusion of daily report collection. Results: We found a reasonably high rate of daily reporting (63.5%) with participants submitting reports on 160 “person-days” out of 252 possible days. Participants submitted daily reports an average of 13 of 21 days. Reports of test strip use frequency varied between the retrospective and daily reports with a relatively higher percentage of days/time using test strips obtained from the daily reports. We also found higher proportions reporting overdose risk reduction behaviors on the daily reports compared with the retrospective reviews. Conclusions: We believe the results support using daily experience sampling to collect information on drug checking behaviors among street drug users. Although resource intensive in comparison to retrospective reports, daily reporting potentially provides more detailed information on test strip use and its association with overdose risk reduction and, ultimately, fewer overdoses. Needed are larger trials and validation studies of daily experience sampling to identify the optimum protocol for collecting accurate information on drug checking and overdose risk reduction behavior.

Fentanyl Test Strips for Harm Reduction: A Scoping Review

“…Notably, interest in FTS use is not always motivated by avoiding fentanyl, as the proliferation of fentanyl into the drug market has led some PWUD preferring fentanyl as their drug of choice 2,30,34,38,39 . Participants in many studies agreed that testing should occur when obtaining a new batch of drugs, purchasing from a new seller, purchasing a large amount, using drugs that look different than prior, using what has been described as a “strong” batch, purchasing from an area with high levels of overdose, or selling to others 39-42 …”

“…Acceptability of FTS may be limited by comfort with preexisting methods for detecting fentanyl, such as the use of color, texture, smell, taste, and tester shots 32,33,43-47 . Purchasing drugs from a known and trusted dealer is often thought of as a sufficient method of protection from fentanyl and may limit acceptability 41,42 …”

“…2,30,34,38,39 Participants in many studies agreed that testing should occur when obtaining a new batch of drugs, purchasing from a new seller, purchasing a large amount, using drugs that look different than prior, using what has been described as a "strong" batch, purchasing from an area with high levels of overdose, or selling to others. [39][40][41][42] Acceptability of FTS may be limited by comfort with preexisting methods for detecting fentanyl, such as the use of color, texture, smell, taste, and tester shots. 32,33,[43][44][45][46][47] Purchasing drugs from a known and trusted dealer is often thought of as a sufficient method of protection from fentanyl and may limit acceptability.…”

“…32,33,[43][44][45][46][47] Purchasing drugs from a known and trusted dealer is often thought of as a sufficient method of protection from fentanyl and may limit acceptability. 41,42…”