Cannabinoid Concentration in Serum (Screening)
This test measures the presence of cannabinoids, the active compounds found in cannabis, in your blood serum. It helps detect recent use of marijuana or related substances.
["This screening can help assess recent cannabis exposure or potential substance use."]
Key facts at a glance
- LOINC
- 74157-9
- Short code
- CANNAB
- Synonyms
- Cannabinoids SerPlBld Ql Scn
- Category
- chemistry
- Sample
- serum
- Container
- Red-top serum tube (no anticoagulant) or plasma tube (EDTA, heparin); glass tubes preferred to avoid plasticizer adsorption for confirmatory testing
- Units
- N/A
- Ref low
- 10
- Ref high
- 50
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- screen
- CPT
- 80307
- SNOMED
- 314529007
- Specimen volume
- 5-10 mL of whole blood yielding 2-5 mL of serum or plasma
- Stability
- Serum/plasma stable for 24 hours at room temperature (20-25°C), 7 days refrigerated at 2-8°C, and up to 30 days frozen at -20°C or colder. For prolonged storage, -70°C is recommended.
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 4–24 hours
- Order
- routine
Why This Test Might Be Ordered
Your healthcare provider may order this test if they suspect recent marijuana use, especially in cases involving impairment, legal concerns, workplace safety, or pre-surgery evaluations. It can also be part of a broader substance use assessment.
What to Expect Before the Test
No special preparation is typically needed. You may be asked to fast for a few hours before the blood draw, but this is not always required for cannabinoid screening. Wear comfortable clothing and plan for the time needed to draw blood.
What Happens During the Test
A healthcare professional will collect a small amount of blood from a vein in your arm. You may feel a slight pinch, but it usually doesn’t cause significant discomfort. The process takes a few minutes.
What the Results Mean
Results are qualitative (positive or negative) and indicate whether cannabinoids were detected in your blood. Positive results suggest recent cannabis use, but they don’t specify the type or amount consumed. Follow-up testing may be needed for confirmation or further details.
Reference range
Negative (cutoff typically 10-50 ng/mL depending on laboratory and assay used; commonly 20 ng/mL for THC metabolites in serum/plasma)N/A
No fasting required. Patient should be informed that cannabinoids may be detectable for days to weeks after use depending on frequency of use, metabolism, and body fat composition. Informed consent may be required for forensic or employment-related testing.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
◆Associated findings1
Short name
Cannabinoid Screen (Serum)
Frequently asked questions
What does a positive result mean?
Can I drink alcohol before this test?
How long will it take to get my results?
Sources
- 1
- 2Lab Tests OnlineSource
- 3
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.
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