Fentanyl analog positivity among near-real-time urine drug test results in patients seeking health care.

Overdose deaths involving synthetic opioids continue to climb. Fentanyl analogs have been identified as important contributors to these overdoses, but little is known about their prevalence in patients seeking health care. This cross-sectional study of urine drug test (UDT) results from July 15, 2019, through March 12, 2020, included patient specimens analyzed using liquid chromatography-tandem mass spectrometry (LC-MS/MS), submitted by health care professionals as part of routine care to detect fentanyl and fentanyl analogs. A convenience sample approach was used to select patient specimens from diverse health care practices across all 50 states, then stratified by fentanyl prescription status. Positivity rates, geographic distribution, and co-occurrence were quantified. The total positivity rate for ten fentanyl analogs was 40.55% in the non-prescribed fentanyl-positive population. The most common fentanyl analogs in this population were 4-ANPP (4-anilino-N-phenethylpiperidine), 30.74%; acetyl fentanyl, 19.40%; and carfentanil, 3.13%. The total positivity rate for four fentanyl analogs was 8.93% in the prescribed fentanyl-positive population, including 4-ANPP, 8.85%; acetyl fentanyl, 0.19%; acryl fentanyl, 0.05%; and 4-FiBF, 0.03%. Counties in Ohio and Kentucky had the highest positivity rates. Acetyl fentanyl and 4-ANPP copositivity occurred in 11.36% of non-prescribed patient specimens. However, acetyl fentanyl and 4-ANPP positivity may not be consistent with fentanyl analog use since both are process impurities, and 4-ANPP is a metabolite of fentanyl. Near-real-time, definitive UDT results reveal fentanyl analogs in patients seeking health care, helping clinicians and public health officials better understand their contribution to overdoses and help mitigate the risks they pose.