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Cannabinoid Serum/Plasma Concentration (Screening)

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

This test measures the presence of cannabinoid compounds in your blood, often used to detect recent cannabis use.

Quick summary

["A cannabis screen helps track substance use and may be part of medical or workplace evaluations."]

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

Key facts at a glance

LOINC
16540-7
Short code
Deprecated Cannabinoids SerPl Ql Cfm
Synonyms
Deprecated Cannabinoids SerPl Ql Cfm
Category
chemistry
Sample
serum
Container
Red-top tube (SST)
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
confirm
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 Does This Test Measure?

The test detects cannabinoids, the active compounds in cannabis, including THC (tetrahydrocannabinol) and CBD (cannabidiol). These substances can be found in your blood for a short period after use.

Why Might You Need This Test?

Your healthcare provider may order this test if you have concerns about recent cannabis use, are part of a substance-use assessment, or are undergoing treatment for related conditions.

How Is the Test Performed?

A blood sample is taken from a vein in your arm. The sample is then analyzed in a lab to measure cannabinoid levels.

What Are the Results Typically Used For?

Results help determine if cannabinoids were recently present in your system, which can inform discussions about substance use, compliance with treatment plans, or legal or workplace requirements.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Clinical Significance: Cannabinoid Testing in Medical and Legal Contexts

Short name

Cannabinoid Screen (Serum/Plasma)

Frequently asked questions

Cannabinoid screening is often used in medical settings to assess exposure to cannabis, particularly in patients with conditions like epilepsy, where cannabis use may be monitored. In legal or workplace contexts, it can verify compliance with substance-free policies or evaluate recent use.
This test is not used to diagnose long-term cannabis dependence or withdrawal symptoms. It provides a snapshot of recent exposure only.
How long do cannabinoids stay in your system?
THC and its metabolites can be detected in blood for about 24 hours after use, depending on factors like frequency of use, metabolism, and individual differences. CBD may linger longer, but its presence is less commonly assessed in routine screens.
Can diet or other substances affect cannabinoid test results?
Diet alone typically does not affect cannabinoid test results. However, if you have consumed other substances (e.g., certain medications), it’s important to inform your healthcare provider to avoid misleading 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