Prevalence and concentration of fentanyl in hair collected for court-ordered mandatory drug testing

Hair testing is often employed by court-ordered mandatory drug testing (COMDT) programs; however, as of December 2024, many of these programs still do not include fentanyl in their testing panels. Further, testing panels including fentanyl for purposes of workplace testing are rare, and concentrations of fentanyl in hair of people who have used drugs are needed to validate future testing cutoffs. In this study, we analyzed 1025 hair specimens, originally collected for COMDT purposes, for 26 substances, including 13 fentanyl-related compounds. Methamphetamine was the most frequently detected compound (n = 266, 26%), followed by hydrocodone (n = 157, 15%). Fentanyl was the most detected fentanyl-related compound, followed by 4-ANPP. Fentanyl was detected in 151 (15%) hair specimens. 12 specimens contained a fentanyl-related compound with no detectable fentanyl. Of the 163 specimens in which fentanyl or a fentanyl-related compound was detected 31 (19%) had no other analytes detected. Using a cutoff of 1 pg/mg the detection rate for fentanyl was 14.7%. Conversely, most commercial testing laboratories utilize cutoffs between 20 and 100 pg/mg. For the 98 specimens with fentanyl concentrations in the quantifiable range (5-2000 pg/mg), the maximum, mean, and median concentrations were 1946, 223, and 55 pg/mg, respectively. An additional 7 specimens had concentrations greater than the upper limit of quantification of 2000 pg/mg with an estimated maximum fentanyl concentration of 9246 pg/mg. Forty-four specimens contained detectable norfentanyl. The norfentanyl: fentanyl ratios ranged from 0.02 to 0.46 with a mean of 0.09. COMDT programs that do not include fentanyl or employ common commercial cutoffs in their testing protocols for fentanyl are potentially missing drug positive specimens.