Harm reduction in the fourth wave of the opioid epidemic: A case series investigation of the effectiveness of definitive vs presumptive urine drug testing for opioid use disorder with co-occurring polysubstance use.

backgroundWe report investigating effectiveness and medical necessity of urine drug testing in a real-world setting comparing near-real-time definitive chromatography/mass spectrometry to real-time presumptive immunoassay for guiding evidence-based harm reduction in a buprenorphine medication for opioid use disorder clinic during the initial swell of the opioid epidemic's fourth wave.

methodsOur exploratory case series included all opioid use disorder patients, most of whom exhibited co-occurring polysubstance use, treated with buprenorphine for one year in a single outpatient clinic. Interventions entailed split-sample urine drug testing comparing "gold standard" definitive laboratory chromatography/mass spectrometry testing to less-costly presumptive point-of-care immunoassay testing, which is more susceptible to false-positive and false-negative results. Analysis evaluated changes to clinical decision-making (i.e., escalation to outpatient crisis management) based on head-to-head definitive chromatography/mass spectrometry vs. presumptive immunoassay testing.

resultsComparison of chromatography/mass spectrometry vs. immunoassay testing in 883 patients eliminated 1847 (14.6%) false-positive results in 458 (51.9%) patients. Mass spectrometry further identified an additional 7086 (69.1%) test results warranting reconsideration of clinical decision-making in 767 (86.9%, p < 0.001) patients. Most false-negative and the additional positive results detected solely by definitive chromatography/mass spectrometry testing comprised substances often associated with polysubstance use in overdose deaths, including methamphetamine, fentanyl, benzodiazepines, heroin and cocaine.

conclusionsMass spectrometry urine drug testing for patients with opioid use disorder and co-occurring polysubstance use provided evidence-based criteria substantiating the notable superiority of definitive testing at nominal additional cost by identifying significant additional instances of risky substance use necessitating harm reduction interventions for substances that would have remained undetected and untreated if testing were limited to presumptive immunoassay testing.