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Cannabinoid Substance Concentration (Serum/Plasma)

Published: August 9, 2026Updated: August 14, 2026

This test measures the amount of cannabinoids, the active compounds found in cannabis, in your blood or plasma. It helps assess recent cannabis use.

Quick summary

["This test checks for recent cannabis exposure in your blood."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 14, 2026Editorial policy

Key facts at a glance

LOINC
8176-0
Short code
CANNAB
Synonyms
Cannabinoids Usub-mCnc
Category
chemistry
Sample
serum
Container
Red-top vacutainer tube (no anticoagulant) for serum; alternatively gray-top (sodium fluoride/potassium oxalate) for forensic specimens requiring chain of custody
Units
N/A
Ref low
0
Ref high
10
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
Method
Gas Chromatography-Mass Spectrometry (GC-MS) or Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) confirmation following immunoassay screening
CPT
80349
SNOMED
167983002
Specimen volume
5-10 mL of whole blood, yielding minimum 2-3 mL of serum
Stability
Serum stable for 24 hours at room temperature (20-25°C); 7 days refrigerated at 2-8°C; up to 30 days frozen at -20°C or below. For forensic specimens, follow chain-of-custody storage requirements.
Hemolysis max
100
Lipemia max
100
Icterus max
50
TAT
24–96 hours
Order
routine

Why This Test Might Be Ordered

Your healthcare provider may order this test if they suspect recent cannabis use, evaluate substance abuse, or investigate symptoms like dizziness, confusion, or impaired coordination. It can also be part of a broader evaluation for legal or workplace reasons.

What to Expect Before the Test

No special preparation is needed. You may have a small needle inserted into your arm for blood collection. If you’re concerned about cannabis use, tell your provider—they can guide you on interpretation.

What the Test Results Mean

Results show cannabinoid concentration levels in your blood. Higher levels may indicate recent cannabis use, but they don’t confirm long-term exposure or tolerance. Results can vary based on how recently you used cannabis and your metabolism.

Possible Results and Next Steps

If levels are above normal, your provider may discuss further testing or ask about recent cannabis use. Low or absent levels suggest no recent use, but they don’t rule out past exposure. Follow-up questions about symptoms or behavior are important.

Reference range

Negative: <10 ng/mL for THC metabolites (varies by laboratory); Cutoff values depend on the specific cannabinoid analyzed (THC, THC-COOH, CBD, CBN). Note: Units marked as N/A - consult laboratory-specific reference ranges and cutoff thresholds for clinical interpretation.N/A

Specimen: serum

No fasting required. Patients should be advised that results may be affected by recent prescription medications, over-the-counter drugs, or dietary supplements. Specimen collection should follow chain-of-custody protocols if used for forensic or employment-related testing.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

Cannabinoid levels in blood are useful for detecting acute cannabis use, which can affect judgment, coordination, and reaction time. Chronic use may not show detectable levels in blood, but other tests (like urine) might. Always consult your provider for interpretation, as results depend on timing, dose, and individual factors.

Short name

Cannabinoid Levels

Frequently asked questions

How long does it take to get results?
Results are typically available within 1 to 3 business days, depending on your lab’s processing time. Your provider will contact you once they’re ready.
Can I drink alcohol before this test?
Alcohol doesn’t interfere with cannabinoid testing, but avoid heavy drinking or substances that could affect your health before testing. Tell your provider about all medications or supplements you’re taking.
What if I have a history of cannabis use?
If you’ve used cannabis before, your provider may still order this test to check for recent use. Levels can vary widely based on how often and how much you use. Discuss your history openly with your provider for accurate interpretation.
  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 14, 2026. · Read our editorial policy