Order Code: FENTS
Fee Code: 21581 (CPT 80354)
Reference Laboratory: Mayo FENTS
The following clarifying language and cut off values will be added to the reference range for Mayo Clinic Laboratories Fentanyl, Serum assay effective May 27, 2025:
Reference Range:
Fentanyl:
Average serum fentanyl concentrations 24 hours after application of transdermal patch:
25 mcg/hour: 0.3-1.2 ng/mL
50 mcg/hour: 0.6-1.8 ng/mL
75 mcg/hour: 1.1-2.6 ng/mL
100 mcg/hour: 1.9-3.8 ng/mL
(Baselt RC. Disposition of Toxic Drugs and Chemical in Man. 12th ed. Biomedical Publications; 2020)
Norfentanyl:
Reference range: Not established
Cutoff concentrations by liquid chromatography tandem mass spectrometry:
Fentanyl: 0.05 ng/mL
Norfentanyl: 0.25 ng/mL
