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Cannabinoid Screening in Serum/Plasma (Qualitative)

Published: August 9, 2026Updated: August 15, 2026

This test detects the presence of certain cannabinoid compounds, including THC (tetrahydrocannabinol) and its metabolites, in your blood. It helps assess recent or recent-use cannabis exposure.

Quick summary

["This screening may be used to check for recent cannabis use, monitor treatment compliance, or support legal or employment-related testing requirements."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 15, 2026Editorial policy

Key facts at a glance

LOINC
110767-1
Short code
CANNA
Synonyms
Cannabinoids Msmt SerPl
Category
chemistry
Sample
serum
Container
Red-top (serum) or plasma separator tube (PST, green-top/lithium heparin); gray-top sodium fluoride/potassium oxalate may be used for forensic specimens to prevent metabolism
Units
N/A
Ref low
1
Ref high
3
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Immunoassay (screening) with confirmation by Gas Chromatography-Mass Spectrometry (GC-MS) or Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)
CPT
80307
SNOMED
31522003
Specimen volume
2-5 mL of whole blood (minimum 1 mL serum)
Stability
Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. For forensic specimens, follow chain-of-custody storage requirements.
Hemolysis max
100
Lipemia max
200
Icterus max
50
TAT
24–72 hours
Order
routine

Why Might This Test Be Ordered?

Your healthcare provider may recommend this test if you’ve been suspected of recent cannabis use, if you’re undergoing treatment for substance use disorder, or if workplace/legal requirements require it. It can also be part of a broader evaluation for certain medical conditions or symptoms linked to substance exposure.

What Does the Test Measure?

The test screens for cannabinoids, including THC and its metabolites (like THC-COOH), which are detectable in blood for a limited time after use. This helps determine if you’ve recently consumed cannabis.

Sample Collection and Preparation

A blood sample is drawn from a vein, typically in your arm. The sample is processed to separate serum or plasma for testing. This is a quick procedure, usually done in a clinic or lab setting.

What Are the Possible Results?

Results are qualitative (positive/negative) rather than quantitative. A positive result indicates recent cannabis exposure, but it doesn’t specify the amount or duration. False positives can rarely occur due to cross-reactivity with other substances.

Reference range

Negative: <10 ng/mL (typical immunoassay cutoff). Quantitative results reported in ng/mL. THC-COOH detection window: single use 1-3 days; chronic use up to 30+ days. Cutoff values vary by laboratory and intended use (employment, clinical, forensic).N/A

Specimen: serum

No special patient preparation required. Patients should be advised that recent prescription or over-the-counter medications (e.g., dronabinol, nabilone, hemp-derived CBD products) may cause positive results. Informed consent may be required in certain clinical or legal contexts.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

Cannabinoid Screen (Serum/Plasma)

Frequently asked questions

How Long Does It Take to Get Results?
Results are typically available within 1 to 3 business days, depending on lab processing times and whether confirmatory testing is needed.
What Does a Positive Result Mean?
A positive result means cannabinoids were detected in your blood, indicating recent cannabis use. This doesn’t necessarily mean you’re addicted or impaired, but it may warrant further discussion with your doctor about your use patterns or next steps.
Can This Test Detect Long-Term Cannabis Use?
No, this test primarily detects recent use. For longer-term exposure, urine or hair testing may be used, as cannabinoids can linger in these specimens for weeks or months.
  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 15, 2026. · Read our editorial policy