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Drug Screen for Opioids (Mass Concentration)

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

This test checks for the presence of opioids, such as codeine, morphine, or fentanyl, in your body. It helps determine if you’ve used these substances recently.

Quick summary

["Detects recent opioid use to guide treatment or safety decisions."]

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

Key facts at a glance

LOINC
27321-9
Short code
Opiates Mlk-mCnc
Synonyms
Opiates Mlk-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 This Test Measures

This test measures the mass concentration of certain opioids in your blood or plasma. It uses a sensitive method to detect very small amounts of these drugs, which can indicate recent use.

Why You Might Need This Test

Doctors may order this test if you’ve been prescribed opioids, have symptoms of opioid use (like drowsiness or slowed breathing), or are suspected of opioid misuse.

How the Test Works

The test involves collecting a blood sample and analyzing it for opioids. The method detects these substances by measuring their mass concentration, often through a specialized laboratory technique.

Common Uses and Scenarios

This test is commonly used in medical settings to monitor patients on opioid therapy, assess for misuse, or evaluate symptoms related to opioid exposure.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Positive results may indicate recent opioid use, which can influence treatment plans, safety precautions, or addiction management. Negative results suggest no detectable opioids in your system at the time of testing.

Short name

Opioid Drug Screening

Frequently asked questions

What does a positive result mean?
A positive result means the test detected opioids in your blood or plasma, which could mean you used them recently. This may affect how your doctor manages your care, especially if you’re prescribed opioids or have concerns about misuse.
How soon after use will the test show results?
The test can detect opioids within hours to days after use, depending on the substance and how your body processes it. For example, morphine may be detected sooner than some longer-lasting opioids.
Can I take anything before the test?
No special preparations are needed, but avoid drinking alcohol or using other substances that could interfere with the test results before your appointment.
  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