Cannabinoid Screening in Serum/Plasma
This test checks for the presence of certain cannabinoid compounds, including THC (tetrahydrocannabinol) and its metabolites, in your blood. It helps determine recent or past cannabis use.
["Detects recent cannabis exposure through measurable metabolites in your blood."]
Key facts at a glance
- LOINC
- 8172-9
- Short code
- CANN
- Synonyms
- Cannabinoids SerPl Ql Scn
- Category
- chemistry
- Sample
- serum
- Container
- Red-top tube (no anticoagulant) for serum; or plasma separator tube (PST) with lithium heparin
- Units
- N/A
- Ref low
- 10
- Ref high
- 50
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- screen
- CPT
- G0434 (drug screen, other than chromatographic; any number of drug classes, by CLIA waived test or moderate complexity test) or 80307 (drug screen, presumptive) depending on payer
- SNOMED
- 272218003
- Specimen volume
- 3-5 mL of whole blood
- Stability
- Serum/plasma stable for 24 hours at room temperature, 7 days at 2-8°C, and up to 30 days frozen at -20°C or colder
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 4–24 hours
- Order
- routine
What This Test Measures
Cannabinoid screening typically includes detection of THC and its primary metabolite, 11-nor-9-carboxy-THC (THC-COOH). These compounds are found in your blood after cannabis use and can persist for varying periods depending on frequency and amount consumed. The test may also include other cannabinoids like CBD (cannabidiol) if specified.
Why It’s Ordered
Doctors may order this test for suspected cannabis use in patients with symptoms like altered mental status, impaired coordination, or for legal, workplace, or pre-employment screening purposes. It can also be used in medical contexts to assess substance use disorders or monitor treatment responses.
Sample Collection and Preparation
A blood sample is drawn from a vein, usually in your arm. The blood is processed to separate serum or plasma, which is then analyzed for cannabinoid compounds. This test is typically performed on fresh or stored serum/plasma samples.
Test Method and Limitations
The test uses immunoassay methods (such as enzyme-linked immunosorbent assay, or ELISA) to detect cannabinoids. While highly sensitive, results can be influenced by factors like recent cannabis use, metabolism differences, or potential cross-reactivity with other substances. False positives may occur if other cannabinoid-like compounds are present.
Reference range
Negative (cutoff typically 10-50 ng/mL depending on laboratory and assay)N/A
No special preparation required. Patients should be advised that this is a screening test and that positive results require confirmatory testing. Informed consent may be required depending on state laws and testing circumstances.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Positive results indicate recent cannabis exposure and can guide treatment decisions, such as counseling or medical management for substance use disorders. Negative results suggest no detectable cannabinoids were present at the time of testing. Interpretation should always be done by a healthcare provider considering clinical context, patient history, and potential confounding factors.
Short name
Cannabinoid Screen
Frequently asked questions
How long does it take to get results?
Can I drink alcohol before this test?
What if my results are positive?
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 15, 2026. · Read our editorial policy