Understand the FDA-cleared fentanyl testing: A clinical evaluation of the SEFRIA fentanyl immunoassay

Dan Wang; Qian Sun; Randal Schneider; Shelby L Cunningham

doi:10.1016/j.drugalcdep.2024.111287

Understand the FDA-cleared fentanyl testing: A clinical evaluation of the SEFRIA fentanyl immunoassay

Drug Alcohol Depend. 2024 Apr 6:259:111287. doi: 10.1016/j.drugalcdep.2024.111287. Online ahead of print.

Authors

Dan Wang¹, Qian Sun², Randal Schneider³, Shelby L Cunningham⁴

Affiliations

¹ Department of Pathology and Laboratory Medicine, Akron Children's Hospital, Akron, OH, USA; Department of Pathology, Northeast Ohio Medical University, Rootstown, OH, USA. Electronic address: dwang@akronchildrens.org.
² Department of Pathology and Laboratory Medicine, Corewell Health William Beaumont University Hospital, Royal Oak, MI, USA; Department of Pathology and Laboratory Medicine, Oakland University William Beaumont School of Medicine, Auburn Hills, MI, USA.
³ Medical & Scientific Affairs, Core Diagnostics, Abbott, Abbott Park, IL, USA.
⁴ Department of Pathology and Laboratory Medicine, Corewell Health William Beaumont University Hospital, Royal Oak, MI, USA.

PMID: 38640864
DOI: 10.1016/j.drugalcdep.2024.111287

Abstract

Background: Screening for fentanyl has been adopted by many clinical laboratories to detect illicit drug use and monitor medication adherence. However, compared to other urine drug testing, fentanyl screening assays are relatively new and therefore their clinical performances are largely unknown. This study extensively evaluated the clinical performance, positive cutoff, and interference profile of SEFRIA fentanyl immunoassay in real patient settings.

Methods: The FDA-cleared cutoff of 1.0 was verified with 21 urine samples with low or undetectable levels of fentanyl. After assay implementation, all screened-positive samples were confirmed by liquid chromatography-tandem mass spectrometry. A new cutoff was derived from the numeric values of the false positive (FP) screening results. The FP rates before and after implementing the new cutoff were compared. Interferences were identified by an untargeted drug analysis and confirmed by spiking experiments.

Results: A total of 3951 screening results were reviewed in the first two months of the assay utilization, 410 were screened-positive, and 157 (38 %) were FP. After a new cutoff of 1.3 was implemented, the FP rate was reduced to 17 % based on 11119 screening results. Trazodone, labetalol, and haloperidol were identified as major interferents, accounting for 56 % of the FP results using the cutoff of 1.3.

Conclusion: By applying the new cutoff and including an interference comment to positive screening results, the FP rate was reduced from initial 38 % to 7.5 % (17 % times 56 %).

Keywords: False positive; Fentanyl screening; Interference; Positive cutoff; SEFRIA fentanyl immunoassay.