Sign in →

Epic Test Code LAB37801 Fentanyl with Metabolite Confirmation, Urine

Additional Codes



Reporting Name

Fentanyl w/metabolite Conf, U

Useful For

Detection and confirmation of illicit drug use involving fentanyl

Performing Laboratory

Mayo Clinic Laboratories in Rochester

Specimen Type


Specimen Required

Collection Container/Tube: Clean, plastic urine collection container

Submission Container/Tube: Plastic, 10-mL urine tube (T068)

Specimen Volume: 3 mL

Collection Instructions:

1. Collect a random urine specimen.

2. No preservative.

Additional Information:

1. No specimen substitutions.

2. No STATS are accepted for this procedure.

3. For situations where chain of custody is required, a Chain-of-Custody Kit (T282) is available. For chain-of-custody testing, order FENTX / Fentanyl with Metabolite Confirmation, Chain of Custody, Urine.

4. If urine creatinine is required or adulteration of the sample is suspected, the following test should be requested, ADULT / Adulterants Survey, Urine. For additional information, please refer to ADULT / Adulterants Survey, Urine.

5. Submitting less than 3 mL will compromise our ability to perform all necessary testing.

Specimen Minimum Volume

2.1 mL

Specimen Stability Information

Specimen Type Temperature Time
Urine Refrigerated (preferred) 14 days
  Frozen  14 days
  Ambient  72 hours

Reference Values


Day(s) and Time(s) Performed

Monday through Sunday

CPT Code Information


G0480 (if appropriate)

Clinical Information

Fentanyl is an extremely fast acting synthetic opioid related to the phenylpiperidines.(1,2) It is available in injectable as well as transdermal formulations.(1) The analgesic effects of fentanyl is similar to those of morphine and other opioids(1): it interacts predominantly with the opioid mu-receptor. These mu-binding sites are discretely distributed in the human brain, spinal cord, and other tissue.(1,3)


Fentanyl is approximately 80% to 85% protein bound. In plasma, the protein binding capacity of fentanyl decreases with increasing ionization of the drug. Alterations in pH may affect its distribution between plasma and the central nervous system (CNS). The average volume of distribution for fentanyl is 6 L/kg (range 3-8).(3,4)


In humans, the drug appears to be metabolized primarily by oxidative N-dealkylation to norfentanyl and other inactive metabolites that do not contribute materially to the observed activity of the drug. Within 72 hours of intravenous (IV) administration, approximately 75% of the dose is excreted in urine, mostly as metabolites with <10% representing unchanged drug.(3,4)


The mean elimination half-life is (1-3):

-IV: 2 to 4 hours

-Iontophoretic transdermal system (Ionsys) terminal half-life: 16 hours

-Transdermal patch: 17 hours (13-22 hours, half-life is influenced by absorption rate)


 - Lozenge: 7 hours

 - Buccal tablet

  - 100 to 200 mcg: 3 to 4 hours

  - 400 to 800 mcg: 11 to 12 hours


In clinical settings, fentanyl exerts its principal pharmacologic effects on the CNS. In addition to analgesia, alterations in mood (euphoria, dysphoria) and drowsiness commonly occur.(1,3) Because the biological effects of fentanyl are similar to those of heroin and other opioids, fentanyl has become a popular drug of abuse.


The presence of fentanyl >0.20 ng/mL or norfentanyl >1.0 ng/mL is a strong indicator that the patient has used fentanyl.


Urine concentrations do not correlate well to serum drug levels. For therapeutic drug management, monitor serum levels using FENTS / Fentanyl, Serum.


For situations where chain of custody is required, a Chain-of-Custody Kit is available, see FENTX / Fentanyl with Metabolite Confirmation, Chain of Custody, Urine.

Analytic Time

2 days

Specimen Retention Time

14 days

Reject Due To


Mild OK; Gross OK




Mild OK; Gross OK



NY State Approved


Method Name

Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)