Roper, Stephen

Abstract Objectives Urine drug testing (UDT) is a critical tool used in medical, forensic, and occupational settings, but interpreting results can be challenging. We performed a study to assess the ability of health care professionals to interpret UDT results accurately. Methods In total, 911 clinical and laboratory professionals in the United States and Canada responded to a survey with questions gauging expertise in UDT interpretation. Responses were analyzed to identify knowledge gaps. Results Toxicologists and laboratory PhD scientists performed well, with means of 4.82 and 4.63 questions answered correctly (out of 6 possible), respectively. Physicians specializing in pathology, emergency medicine, primary care, and internal medicine, however, displayed concerning knowledge gaps, as did laboratorians with nondoctoral degrees. Experience and training correlated with interpretation accuracy. Identification of simulated compliance as well as understanding opioid exposure, metabolism, and immunoassay cross-reactivity were among the most clinically significant knowledge gaps. More than 30% of survey respondents indicated that they would seek UDT information from the internet or peers rather than clinical or laboratory experts. Conclusions The study highlighted the need for targeted education and better collaboration between clinical and laboratory experts and other health care professionals to ensure that when physicians order UDT, they can accurately interpret results and reduce harm.

Abstract Background Fentanyl is a synthetic opioid associated with illicit drug use and overdose deaths. The SEFRIA Immunalysis (IAL) and ARK fentanyl assays are both FDA-cleared, open channel immunoassays for fentanyl detection in urine. However, limited data are available in the literature comparing these assays. The objective of this study was to perform a direct comparison of these two fentanyl immunoassays. Methods IAL and ARK fentanyl immunoassays were performed on a Roche Cobas e602 automated chemistry analyzer. Repeatability and total imprecision were compared by diluting fentanyl into urine at concentrations above, below, and at the manufacturers’ cutoffs of 1.0 ng/mL. Cross-reactivity was assessed for norfentanyl and the fentanyl analogs acetylfentanyl, acrylfentanyl, and furanylfentanyl. Concordance was assessed in 90 patient samples using liquid chromatography-tandem mass spectrometry (LC-MS/MS) as the gold standard. Results Repeatability varied from 11.4%–17.8% on the IAL assay and 2.8%–5.5% on the ARK assay. Total imprecision was 18.9%–40.7% on the IAL assay and 2.9%–6.4% on the ARK assay. Both assays cross-reacted with acetylfentanyl (∼100%), acrylfentanyl (∼100%), and furanylfentanyl (∼20%), but only the ARK assay cross-reacted with norfentanyl (∼3%). An admixture of 0.5 ng/mL fentanyl and 6 ng/mL norfentanyl produced a positive result on the ARK assay. Total concordance between IAL and ARK for 90 tested patient samples was 93% (kappa = 0.85). Relative to LC-MS/MS, the IAL assay had a concordance of 90% (kappa = 0.79) and the ARK assay had a concordance of 94% (kappa = 0.88). Including norfentanyl in the LC-MS/MS confirmation increased the concordance of the ARK to 96% (kappa = 0.90). Conclusions The ARK assay recognized the metabolite norfentanyl, demonstrated superior precision, and had better concordance with LC-MS/MS compared to the IAL assay.