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Opioid Concentration (Serum or Plasma)

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

This test measures the amount of opioids (pain-relieving drugs) in your blood, often checked if you’re prescribed opioids or experiencing suspected opioid use.

Quick summary

["Knowing your opioid levels helps doctors monitor pain management and detect potential risks like dependence or overdose."]

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

Key facts at a glance

LOINC
106718-0
Short code
SCHEDULEDOPIOID
Synonyms
—
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
cms-assessment
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 doctor may order this test to assess how your body is responding to opioid medication, check for drug interactions, or evaluate symptoms like confusion, slowed breathing, or withdrawal. It can also be used during detoxification or to monitor long-term use.

What to Expect Before the Test

No special preparation is needed, but you may be asked to fast for 8–12 hours if the test involves a blood draw. Bring any current medications or supplements you’re taking, as they could affect results.

How the Test Works

A small sample of blood (serum or plasma) is taken from a vein, usually in your arm. The sample is then tested in a lab using methods like immunoassay or chromatography to measure opioid levels.

What the Results Mean

Results are typically reported as a concentration (e.g., micrograms per milliliter). High levels may indicate recent opioid use, while very low levels could suggest poor absorption or medication changes. Your doctor will interpret results in the context of your medical history and symptoms.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance

Short name

Opioid Level

Frequently asked questions

How opioids in your system can affect health, including risks of addiction, respiratory depression, or liver/kidney strain, especially with long-term use or mixing with other substances.
Opioid levels help doctors adjust dosages, detect misuse, or identify complications like tolerance or withdrawal symptoms. Chronic use may also require monitoring for organ function.
How long does it take to get results?
Results are usually available within 1–3 business days, depending on your lab. Your doctor will contact you once they’re ready.
Can I take anything before the test?
If fasting is required, avoid food/drinks (except water) for 8–12 hours beforehand. If not, follow your doctor’s instructions to avoid false results.
  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