Urine Screenings are Ineffective at Detecting Marijuana Use or Impairment

Individual practitioners may find themselves in trouble with the Florida Department of Health for testing positive of “marijuana”. Chapman Law Group handles cases like these daily. The outcomes of the investigation are not always predictable, and this is why you need experienced healthcare defense attorneys who can analyze the particularities of your case. If you tested positive for marijuana, I suggest you call Chapman Law Group immediately and speak to one of our qualified defense attorneys who can help you create a defense strategy.

If you do not make use of marijuana, you might be surprised to know that you may still test positive for THC in urine screenings. The question then becomes: do you use hemp derivative products? If so, this might be the culprit behind your positive test results.

The main issue at the center of laboratory testing is that marijuana and hemp come from the same plant, Cannabis Sativa L, but while marijuana is illegal, hemp is not. The Hemp Farming Act of 2018 was recently passed into law on December 20, 2018, and it formally addressed the differences between the two. The Hemp Farming Act effectively differentiates hemp from marijuana and implements changes to the Controlled Substances Act of 1970 so that now, hemp and hemp derivative products are federally recognized as legal. Most significantly, legislators specifically legalized THC originating from hemp. [1]

How does this affect licensees?

While a licensee may have a valid defense for testing positive for THC, the Department only cares about the positive result, and they will open an investigation. Current laboratory testing is designed for ease of collection and analysis, and it’s cheap. This helps employers and agencies produce results quickly. The problem is that speed and cost-effectiveness come in spite of reliable methods to differentiate between different metabolites, or their origins.

Urine screenings do not differentiate between THC and CBD

Urine testing for marijuana focuses on the detection of THCA, which is the primary metabolic product of THC in urine.[2] Interestingly, most of the antibodies we produce to react with THCA, will cross-react with CBD.[3] While THC and CBD ingestion may in fact have very different effects on our bodies, regular urine testing methods are not designed to detect subtle differences. Superficially, our bodies react similarly to THC and CBD.  The result is that individuals who use products containing CBD can test positive in laboratory tests designed to detect marijuana use. It’s difficult to disprove the findings of a positive urine screening, but it’s not impossible. A licensee will need an expert toxicologist to assist in a finding of a “false-positive”. Chapman Law Group has successfully retained impressive experts who produce opinions in support of this license defense.

Urine screenings cannot identify the source of THC: marijuana vs hemp

Both marijuana and hemp contain THC, however, their levels concentrations differ.[4][5] If you make use of hemp products, such as CBD oil, you may be consuming THC as well as CBD.[6] It is therefore possible that a licensee test positive for THC even when they do not make use of marijuana.[7] Urine tests simply do not identify where the THC originates from. Resulting positive is enough for the Department to initiate an investigation against your license.

Urine screenings cannot conclusively prove impairment

THC urine screenings today are not a conclusive finding of impairment. Scientific research regarding marijuana usage and its relationship with driving demonstrates how, testing positive for THC doesn’t necessarily correlate with impairment.

Laboratory tests and driving studies show that the effects of cannabis use between individuals vary more than they do with alcohol because of tolerance and different absorptions rates of THC. Furthermore, low concentrations of THC do not increase the rate of accidents, in fact, they may even decrease them. Most interestingly, scientist have conducted “culpability studies” to determine whether using cannabis is linked to traffic accident. The evidence collected in these culpability studies is inconclusive, and similar disagreement has never existed in the literature on alcohol use and risk of car accidents.[8] These findings are applicable to licensees under investigation by the Department of Health.

The scientific community is still unsure as to what concentrations of THC, if any, are enough to suggest impairment. Therefore, while testing positive for THC derived from marijuana can result in a Department investigation, a positive result may not be enough for a finding of impairment.


As mentioned above, if you test positive for THC, the Department will open an investigation against you – you will need evidentiary and scientific support for your license defense and a healthcare defense attorney who has experience with this new and evolving area of law. Chapman Law Group has the experience, the resources, and reputable experts for your license defense.

Chapman Law Group (CLG) is a professional health care law litigation firm with offices in Florida and Michigan. For 35 years, CLG has defended the rights of health care professionals, providers and corporations involved in the delivery of health care at all levels.  We believe the dedicated men and women who provide health care deserve an exceptional defense when their integrity and actions are called into question. Look us up on the web www.chapmanlawgroup.com or call Florida at 941-893-3449, Michigan at 248-644-6326, Ohio at 614-360-3848.

Sara A. Bazzigaluppi, Esq. is a Florida-licensed attorney with a focus on professional licensing defense.  Sara is dedicated to the defense of medical professionals at every step of the process, from Department of Health investigations, to administrative complaints, and hearings before Boards or the Division of Administrative Hearings. Sara also has experience with emergency restriction and suspension orders, IPN/PRN contracts, and settlement negotiations with the Department of Health. Sara has a particular interest in substance abuse matters relating to impairment and safety to practice.

[1] https://www.congress.gov/bill/115th-congress/house-bill/5485/text

[2] Grotenhermen F (2003) Pharmacokinetics and pharmacodynamics of cannabinoids. Clin Pharmacokinet 42: 327-360

[3] Tanaka H (2011) Immunochemical approach using monoclonal antibody against Delta(9)-tetrahydrocannabinolic acid (THCA) to discern cannabis plants and to investigate new drug candidates. Curr Drug Discov Technol 8: 3-15

[4] Bosy TZ, Cole KA (2000) Consumption and quantitation of delta9-tetrahydrocannabinol in commercially available hemp seed oil products. J Anal Toxicol 24: 562-566.

[5] Holler JM, Bosy TZ, Dunkley CS, Levine B, Past MR, Jacobs A (2008) Delta9-tetrahydrocannabinol content of commercially available hemp products. J Anal Toxicol32: 428-432.

[6] Id.

[7] Id.

[8] Sewell, R Andrew et al. “The effect of cannabis compared with alcohol on driving” American journal on addictions vol. 18,3 (2009): 185-93.

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