Your complete guide to cannabis in cannabis drug testing Official SAMHSA data · No product sales · TryCannabis.org

Authoritative Data Sources and Research

CannabisDrugTest.org is built on peer-reviewed research, federal agency documents, and primary legal sources. This page lists every major source we cite, with links where available. If you want to verify a claim on this site, the source is here.

Federal Agencies

SAMHSA (Substance Abuse and Mental Health Services Administration)

U.S. Department of Transportation (DOT)

Other Federal Sources

  • NIDA (National Institute on Drug Abuse): nida.nih.gov
  • NHTSA (National Highway Traffic Safety Administration): Cannabis impaired driving research
  • FMCSA Drug & Alcohol Clearinghouse: CDL driver violation database
  • SEAD 4 Adjudicative Guidelines: Security clearance Guideline H
  • Executive Order 12564: Federal employee drug-free workplace
  • Drug-Free Workplace Act: 41 U.S.C. §§ 8101–8106

Key Researchers

Marilyn A. Huestis, PhD

Former Chief, Chemistry and Drug Metabolism Section, NIDA/NIH. The most-cited researcher on cannabinoid pharmacokinetics. Currently at Thomas Jefferson University and Huestis & Smith Toxicology LLC. Her 2007 review in Chemistry & Biodiversity is the standard reference for human cannabinoid pharmacokinetics.

Erin L. Karschner, PhD

Former NIDA researcher. Currently at Armed Forces Medical Examiner System, Division of Forensic Toxicology. Major contributor to chronic user pharmacokinetic studies.

Essential PubMed Citations

These are the peer-reviewed papers cited throughout this site. PubMed IDs link to the original abstracts.

Pharmacokinetics

  • PMID 17712819 — Huestis MA. "Human cannabinoid pharmacokinetics." Chem Biodivers. 2007;4(8):1770-1804. (PMC2689518)
  • PMID 1338215 — Huestis et al. "Blood cannabinoids. I. Absorption of THC and formation of 11-OH-THC and THCCOOH during and after smoking marijuana." J Anal Toxicol. 1992;16(5):276-282.
  • PMID 9780137 — Huestis & Cone. "Urinary excretion half-life of 11-nor-9-carboxy-delta9-tetrahydrocannabinol in humans." Ther Drug Monit. 1998;20(5):570-576.
  • PMID 19631478 — Lowe RH et al. "Extended urinary Δ9-tetrahydrocannabinol excretion in chronic cannabis users precludes use as a biomarker of new drug exposure." Drug Alcohol Depend. 2009;105(1-2):24-32. (PMC2763020)
  • PMID 23449702 — Bergamaschi MM et al. "Impact of prolonged cannabinoid excretion in chronic daily cannabis smokers' blood on per se drugged driving laws." Clin Chem. 2013;59(3):519-526. (PMC3717350)

Exercise and THC

  • PMID 24018317 — Wong A et al. "Exercise increases plasma THC concentrations in regular cannabis users." Drug Alcohol Depend. 2013.
  • PMID 25258138 — Westin AA et al. "Can physical exercise or food deprivation cause release of fat-stored cannabinoids?" Basic Clin Pharmacol Toxicol. 2014.

Secondhand Smoke

  • PMID 25326203 — Cone EJ et al. "Non-smoker exposure to secondhand cannabis smoke. III." J Anal Toxicol. 2015. (PMC4342697)

CBD and Drug Tests

  • PMID 33146714 — Dahlgren MK et al. JAMA Psychiatry, 2020. Full-spectrum CBD causing positive THC tests.

False Positives

  • PMID 24986836 — Saitman A et al. "False-positive interferences of common urine drug screen immunoassays: a review." J Anal Toxicol. 2014;38(7):387-396.
  • PMID 28012771 — Moeller et al. (2017). Immunoassay positive predictive values.

Niacin Toxicity

  • PMID 17443121 — CDC MMWR (2007). Niacin toxicity from drug test evasion.
  • PMID 17418450 — Mittal MK et al. "Toxicity from the use of niacin to beat urine drug screening." Ann Emerg Med. 2007.
  • PMID 29686792 — Acute liver failure from niacin megadose.
  • PMID 20138459 — Multi-organ toxicity case report.
  • PMID 24711953 — Cardiac arrhythmia case report.

Hair Testing

  • PMID 27648739 — Taylor et al. (2017). Hair testing sensitivity in light vs. heavy users.
  • PMID 17881659 — Huestis (2007). Racial bias evaluation in cannabis hair testing.

Industry Data

Key Journals

  • Journal of Analytical Toxicology (Oxford University Press)
  • Clinical Chemistry (AACC/Oxford)
  • Drug and Alcohol Dependence (Elsevier)
  • Drug Testing and Analysis (Wiley)
  • JAMA Psychiatry
  • Therapeutic Drug Monitoring
  • Annals of Emergency Medicine

Court Cases

  • Noffsinger v. SSC Niantic Operating Co. (D. Conn. 2017) — DFWA does not preempt state cannabis protections
  • Callaghan v. Darlington Fabrics (R.I. Super. 2017) — First decision finding implied private right of action
  • Barbuto v. Advantage Sales, 477 Mass. 456 (2017) — Interactive accommodation process required
  • Coats v. Dish Network, 350 P.3d 849 (Colo. 2015) — Federal illegality trumps state lawful activity
  • Ross v. RagingWire Telecommunications (Cal. 2008) — Superseded by AB 2188
  • Whitmire v. Wal-Mart Stores (D. Ariz.) — Positive test alone insufficient to prove impairment
  • Ceballos v. NP Palace (Nev. 2022) — Recreational use not protected for current employees
  • Emerald Steel v. BOLI, 348 Or. 159 (2010) — Federal CSA preemption of state accommodation
  • Palmiter v. Commonwealth Health Systems (PA Super. 2021) — Private right of action recognized
  • Horn v. Medical Marijuana, Inc. (U.S. Sup. Ct. 2025) — CDL driver RICO claim against CBD manufacturer
  • Commonwealth v. Gerhardt (Mass. SJC 2017) — SFST limitations for cannabis impairment
  • State v. Olenowski (NJ 2023) — DRE testimony limited to "consistent with" phrasing
  • Deborah M. v. Superior Court (Cal. 2005) — California prohibits hair follicle testing in custody cases

Why These Sources Matter

Most cannabis drug testing information online is either marketing for products or repetition of folklore. This site exists to be a counter-example: every claim is sourced, every source is identified, and you can verify anything we say against the original literature. If you find a claim on this site that lacks proper sourcing, please let us know so we can fix it.

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