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Fentanyl and Norfentanyl in Plasma (Quantitative)

Published: August 9, 2026Updated: August 16, 2026

This test measures the amounts of fentanyl and its active metabolite, norfentanyl, in your blood plasma. These substances are used in pain management and may appear in your system after exposure.

Quick summary

["Understanding your fentanyl and norfentanyl levels helps doctors monitor pain treatment and detect potential overdoses."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
81273-5
Short code
fentaNYL+Norfentanyl pnl Spec
Synonyms
fentaNYL+Norfentanyl pnl Spec
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
86430
Specimen volume
5 mL
Stability
Room temperature: 4h, Refrigerated: 24h, Frozen: 7d
Hemolysis max
500
Lipemia max
1000
Icterus max
500
TAT
4–24 hours
Order
routine

Why This Test Is Done

Your healthcare provider may order this test if you’re receiving fentanyl-based pain medication, experiencing symptoms of opioid overdose (such as confusion, slow breathing, or unconsciousness), or if you’ve been exposed to fentanyl in other ways (e.g., illicit drugs). It can also be used to assess drug levels in research or specialized clinical settings.

What to Expect Before the Test

No special preparation is needed. You’ll likely have a small needle inserted into your arm or vein to draw a blood sample. If you’re on blood thinners, inform your provider beforehand.

What the Test Results Mean

Results show the concentration of fentanyl and norfentanyl in your plasma. Higher levels may indicate recent use, overdose risk, or improper dosing. Your doctor will interpret these results in the context of your medical history and symptoms.

Common Reasons for Testing

This test is primarily used in clinical settings to monitor patients on fentanyl therapy, evaluate suspected overdoses, or assess drug metabolism in specialized studies. It’s not a routine screening test for general health.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Fentanyl & Norfentanyl Plasma Level

Frequently asked questions

What does a high level of fentanyl or norfentanyl mean?
High levels may suggest recent fentanyl exposure, improper dosing, or potential overdose. Your doctor will consider these results alongside other symptoms and tests to guide treatment decisions.
How long does it take to get results?
Results are typically available within 1–3 business days, depending on lab processing times and your healthcare provider’s workflow.
Can I drink alcohol before this test?
No, avoid alcohol for 24 hours before the test, as it may affect blood chemistry and test accuracy.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy