Evaluation of Infectious Disease Test Ordering and Positivity Rates in Illicit Fentanyl Users

Matthew Lloyd, Eric M. Ransom, Neil W. Anderson, Christopher W. Farnsworth

Research output: Contribution to journalArticlepeer-review


BACKGROUND: The emergence of illicit fentanyl use has resulted in considerable morbidity and mortality. Although illicit use of other opioids has been associated with transmission of viral and bacterial infections, limited data exist for the prevalence of infectious diseases among illicit fentanyl users. The purpose of this study was to assess the likelihood of infectious disease testing and infection prevalence among illicit fentanyl users. METHODS: Results from urine drug screens (UDSs) performed from August 13, 2019, to October 16, 2019, were obtained from the laboratory information system with concurrent microbial testing. Patients were categorized based on UDS results, and illicit drug use was inferred from physician encounter notes in the electronic medical record. RESULTS: Suspected illicit drugs users with fentanyl detected by UDS were more likely to be screened [odds ratio (OR): 1.7; 95% CI, 1.26-2.4] and test positive for hepatitis C virus (HCV) by immunoassay (OR: 5.89; 95% CI, 2.93-11.31) than patients without drugs detected. Patients with suspected illicit fentanyl use who were discharged from the emergency department (ED) were less likely to be tested for HCV than patients in outpatient settings (OR: 3.47; 95% CI, 1.05-10.4) and inpatient settings (OR: 17.43; 95% CI, 6.53-45.88). Patients with suspected illicit fentanyl use were more likely to have infected abscesses or wounds (OR: 5.12; 95% CI, 2.07-13.7) and Staphylococcus aureus infections (OR: 4.5; 95% CI, 1.59-12.28) than patients without drugs detected. CONCLUSIONS: Patients with a positive UDS for fentanyl and suspected illicit use were more likely to test positive for HCV, were rarely screened for HCV in the ED, and had an increased risk of invasive S. aureus wound or abscess infection. These findings may represent considerable barriers to care for patients who use fentanyl illicitly.

Original languageEnglish
Pages (from-to)79-92
Number of pages14
JournalThe journal of applied laboratory medicine
Issue number1
StatePublished - Jan 12 2021


  • Fentanyl
  • illicit drug use
  • infections


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