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A Comparative Analysis of Two Commonly Used FDA-Approved Immunoassays for Fentanyl Detection
K H Brian Lam1, Marlen Menlyadiev2,3, Vincent Buggs1
1Department of Pathology and Laboratory Medicine, David Geffen School of Medicine, University of California Los Angeles, Los Angeles, CA, United States.
The Journal of Applied Laboratory Medicine
|June 4, 2024
Summary
The Lin-Zhi FEN2 assay demonstrated higher specificity than the Ark Diagnostics ARK II assay for fentanyl screening in urine. Both immunoassays performed well, but FEN2 showed fewer false positives in this comparative study.
Area of Science:
- Clinical Chemistry
- Toxicology
- Forensic Science
Background:
- Urine fentanyl screening is crucial due to the ongoing opioid epidemic.
- Immunoassays are standard for high-throughput drug screening on automated systems.
- This study compares the Ark Diagnostics ARK II and Lin-Zhi FEN2 fentanyl assays.
Purpose of the Study:
- To evaluate and compare the performance of two widely used urine fentanyl immunoassays: ARK II and Lin-Zhi FEN2.
- To assess sensitivity and specificity of each assay against LC-MS/MS confirmation.
Main Methods:
- 434 urine samples analyzed using Lin-Zhi FEN2 and Ark Diagnostics ARK II assays on a Cobas c502 platform.
- Samples tested immediately or frozen; confirmation by liquid chromatography-tandem mass spectrometry (LC-MS/MS).
- LC-MS/MS limit of detection set at 1 ng/mL for fentanyl/norfentanyl.
Main Results:
- ARK II: 90.4% sensitivity, 97.8% specificity (11 false negatives, 7 false positives).
- Lin-Zhi FEN2: 89.5% sensitivity, 99.4% specificity (12 false negatives, 2 false positives).
- Lin-Zhi FEN2 exhibited superior specificity with significantly fewer false positives.
Conclusions:
- Both ARK II and Lin-Zhi FEN2 immunoassays effectively detect fentanyl in urine.
- The Lin-Zhi FEN2 assay demonstrated slightly better specificity in this study.
- Discrepancies between assays were mostly observed near their respective detection cutoffs.
