A new automated urine fentanyl immunoassay: technical performance and clinical utility for monitoring fentanyl compliance

BackgroundOpiate and other drugs of abuse screening assays have been available for many years, and successfully utilized for monitoring patient medication compliance and for detecting misuse. However, immunoassays designed to rapidly detect the highly potent synthetic opioid, fentanyl, have not been available.MethodsWe evaluated a new fentanyl homogeneous enzyme immunoassay (HEIA) (Immunalysis Corporation) for its ability to accurately detect fentanyl in 307 urine samples from patients prescribed chronic opioid therapy. Samples were screened by HEIA and confirmed by LC–MS/MS and ELISA for diagnostic comparison. HEIA precision and interference studies were performed.ResultsHEIA diagnostic sensitivity, specificity and accuracy were 97%, 99%, and 99%, respectively, in comparison with LC–MS/MS and ELISA. HEIA detected 37 of the 38 LC–MS/MS positive samples identified in our initial evaluation, including some that contained very low levels of fentanyl, < 1 ng/ml (< 3 fmol/l). HEIA showed minimal cross-reactivity with other opioid analgesics and commonly encountered drugs. Interferences by common urine contaminants were negligible, but we observed considerable signal suppression in acidic samples (pH < 4.0).ConclusionsThe HEIA urine fentanyl assay allows for rapid and accurate fentanyl detection, illustrating its utility in monitoring fentanyl compliance and abuse.