: Mefentanyl, Serum or Plasma, by Mass Concentration

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

: This test measures the amount of mefentanyl, a synthetic opioid, in a sample of serum or plasma. It is used to detect exposure to this substance, most often in emergency or forensic settings.

Quick summary

[": The test uses a blood specimen to look for and measure mefentanyl, a potent synthetic opioid."]

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

Key facts at a glance

LOINC: 17275-9
Short code: Me-fentanyl SerPl-mCnc
Synonyms: Me-fentanyl SerPl-mCnc
Category: chemistry
Sample: serum
Container: Red-top tube (SST)
Units: N/A
Fasting: false
Population: adult
Sex: all
Age range: 18–65 years
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

: What Is Being Measured

: Mefentanyl is a synthetic (man-made) opioid related to fentanyl. This test measures its mass concentration — that is, the amount of the drug present per volume of serum or plasma. Detection may be part of a broader drug screen or a targeted confirmation test.

: Why the Test Is Ordered

: The test may be ordered when a person shows signs of opioid exposure or overdose, when a clinician needs to confirm which substance is involved, or as part of workplace, forensic, or monitoring evaluations. Results help guide medical care and inform safety decisions.

: How the Sample Is Collected

: A blood sample is drawn from a vein, usually in the arm, and the serum or plasma is separated from the blood cells in the laboratory. The collection itself is quick and typically causes only brief discomfort.

: What Results Mean

: A detectable result indicates that mefentanyl is present in the sample. Because testing methods and cutoff levels vary between laboratories, results should always be interpreted by the ordering clinician in the context of symptoms, history, and any other tests performed. This page does not provide a specific reference range.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

: Mefentanyl

Frequently asked questions

: Does a positive result always mean an overdose occurred?

: No. A positive result shows that the substance was detected, but it does not by itself indicate how much was taken or whether harmful effects are present. The clinician interprets the result together with the person's symptoms and history.

: Can this test tell how long ago the drug was used?

: Not precisely. Blood levels reflect recent exposure and change quickly over time, so this test is best used to detect current or very recent presence rather than to pinpoint timing.

: Are over-the-counter or prescription drugs likely to cause a false result?

: Testing methods differ, and possible cross-reactivity varies by laboratory. Any unexpected result should be discussed with the clinician, who may request confirmatory testing using a more specific method.

Sources

1
MedlinePlus — Laboratory TestsSource
2
Lab Tests OnlineSource
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