Cannabinoid concentration in hair (substance concentration, qualitative screening)
This test measures the presence of cannabinoids (compounds found in cannabis) in your hair, often used to detect recent or long-term exposure to marijuana.
["Hair cannabinoid testing helps track past cannabis use over time."]
Key facts at a glance
- LOINC
- 40800-5
- Short code
- THC-HAIR
- Synonyms
- Cannabinoids Hair Ql Scn
- Category
- chemistry
- Sample
- serum
- Container
- Sterile specimen container or foil packet for hair sample
- Units
- N/A
- Fasting
- false
- Population
- adult
- Sex
- all
- Age range
- 1–99 years
- Method
- screen
- CPT
- 80307
- SNOMED
- 407615008
- Specimen volume
- 100 mg of hair (approximately 50-100 strands), cut close to the scalp, typically 3 cm segment for 90-day detection window
- Stability
- Room temperature: stable for 2 weeks; Refrigerated (2-8°C): stable for 3 months; Frozen (-20°C): stable for 1 year
- Hemolysis max
- 500
- Lipemia max
- 1000
- Icterus max
- 500
- TAT
- 24–72 hours
- Order
- routine
Why This Test Is Done
Your healthcare provider may order this test if you have concerns about cannabis use, require a drug screening for employment, legal reasons, or to monitor ongoing exposure. Hair testing can reveal use that occurred months or even years prior, as cannabinoids remain in hair for extended periods.
How the Test Works
A small sample of your hair is collected. The test analyzes the chemical composition to detect cannabinoid compounds. Results are qualitative (positive/negative) rather than quantifying exact amounts.
What to Expect Before the Test
No special preparation is needed. Wear comfortable clothing if you’ll need to shave or trim hair near the roots, as the test requires a sample from the scalp.
What the Results Mean
A positive result indicates detectable cannabinoids in your hair, suggesting past exposure. A negative result means no detectable cannabinoids were found in this sample. Consult your provider for interpretation based on clinical context.
Reference range
Negative (cutoff: typically 1 pg/mg or 0.1 ng/mg depending on laboratory)N/A
No special preparation required. Patient should be advised that hair coloring, bleaching, or chemical treatments may affect results
Clinical interpretation
How abnormal results are interpreted and what conditions they suggest.
Hair cannabinoid testing is useful for detecting long-term cannabis use, which may not be captured by urine or blood tests. It can help assess compliance with treatment plans, screen for workplace or legal purposes, or investigate suspected exposure in cases where other tests are inconclusive.
Short name
Cannabinoid hair test
Frequently asked questions
How long does it take to get results?
Can I use hair products or styling treatments before the test?
What does a positive result mean?
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