Cannabinoid (THC and CBD) Concentration in Whole Blood
This test measures the levels of cannabinoids, including tetrahydrocannabinol (THC) and cannabidiol (CBD), in your blood. It helps determine recent cannabis use.
["This test checks for recent cannabis exposure by measuring specific compounds in your blood."]
Key facts at a glance
- LOINC
- 42630-4
- Short code
- CANNB
- Synonyms
- Cannabinoids Bld Ql
- Category
- chemistry
- Sample
- whole-blood
- Container
- Gray-top sodium fluoride/potassium oxalate tube (preferred for forensic samples) or red-top tube without anticoagulant; avoid gel separator tubes
- Units
- N/A
- Ref low
- 1
- Ref high
- 2
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 18–65 years
- Method
- Immunoassay (screening) with Gas Chromatography-Mass Spectrometry (GC-MS) or Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) confirmation
- CPT
- 80349
- SNOMED
- 3219009
- Specimen volume
- 5-10 mL whole blood
- Stability
- Room temperature: 24 hours; Refrigerated (2-8°C): 7 days; Frozen (-20°C or below): 30 days. For forensic samples, refrigerate immediately and analyze within established chain-of-custody timeframes.
- Hemolysis max
- 100
- Lipemia max
- 100
- Icterus max
- 50
- TAT
- 4–72 hours
- Order
- routine
Why This Test Might Be Ordered
Your healthcare provider may order this test if you have concerns about recent cannabis use, such as after suspected exposure, for legal purposes, or as part of a medical evaluation for symptoms linked to cannabis use, like altered mood or physical effects.
What to Expect Before the Test
No special preparation is needed. You may have a small needle inserted into your arm or vein to draw a blood sample. The process usually takes a few minutes.
What the Results Mean
Results show the concentration of cannabinoids in your blood. Higher levels may indicate recent cannabis use, but they don’t confirm the exact time or amount consumed. Interpretation depends on clinical context and your healthcare provider’s guidance.
Common Reasons for Testing
This test is often used in legal settings (e.g., employment, driving under the influence), medical evaluations, or to monitor substance use in treatment programs.
Reference range
Negative: THC < 1 ng/mL; Positive cutoff typically ≥ 1 ng/mL or ≥ 2 ng/mL depending on laboratory protocol. Detection window in whole blood: 1-2 days after single use; up to 7-25 days with chronic heavy use.N/A
No fasting required. Patient should be informed that cannabinoid use may be detected. Chain of custody documentation required for forensic or legal samples. Collect specimen prior to administration of any medications when possible.
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Cannabinoid levels in blood can reflect recent cannabis exposure and may correlate with acute effects such as altered perception, relaxation, or impaired coordination. However, these effects can vary widely among individuals. Chronic use may affect long-term health, though blood levels alone don’t fully capture this risk.
Short name
Cannabinoid Blood Test
Frequently asked questions
How long does it take to get results from this test?
Can I drink alcohol before this test?
Does this test detect other drugs besides cannabis?
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