- The presence of fentanyl or norfentanyl >LOQ indicates exposure to fentanyl within 3 days.
- Fentanyl is metabolized primarily by oxidative N-dealkylation to norfentanyl.
Fentanyl → Norfentanyl
Approximate Detection Times
||Detection Time* up to
*These are approximate detection times for the drug or metabolites in urine. The actual detection time depends on dose, frequency of
use, and individual metabolism.