Attorney and Author headshot sitting in dark suit against a tan backgroundBy George F. Indest III, J.D., M.P.A., LL.M., Board Certified by The Florida Bar in Health Law and Hartley Brooks, Law Clerk, The Health Law Firm

When representing licensed health professionals, our firm often encounters issues regarding positive drug tests that employers request. These clients include nurses, pharmacists, dental professionals, mental health counselors, therapists, etc. Job seekers should be aware that employers, particularly large companies and government organizations, may require drug tests as part of the hiring process. Medical and nursing students should be aware that prior to beginning clinical rotations in a hospital or medical facility, they will be given a drug screening test.

These issues are particularly relevant when a health professional has applied to a hospital, a medical organization, or a placement agency for work in a hospital and must submit to a pre-employment drug test. The client often contends that a positive result is a false positive and that some other substance must be responsible for it.

A positive result for any drug for which you do not have a valid prescription from a physician, including marijuana, can have severe and far-reaching consequences. It could result in being eliminated from consideration for a new job or termination from a current position. It can also result in a complaint against your professional license, which could lead to suspension or revocation. This could be devastating to your career and your future job prospects. Our firm is routinely called on to defend health professionals in such situations.
This blog series will discuss the potential causes for false positive results on THC drug tests and marijuana’s changing legal status on employer-ordered drug testing.

Remember to read Part 1 and Part 2 of this blog series! Part 1 deals with substances that may cause a false positive for amphetamines. Part 2 deals with substances that may cause a false positive for cocaine.

Marijuana (THC) False Positives.

The primary psychoactive chemical in cannabis is delta-9-tetrahydrocannabinol commonly referred to as just tetrahydrocannabinol or THC. Urine drug screens are designed to detect 11-nor-delta-9-tetrahydrocannabinol-9-carboxylic acid (9-carboxy-THC). THC can be detected in urine for up to three (3) days for single usage but up to four to six (6) weeks after stopping long-term heavy use.

A false positive drug test occurs when the test detects a substance that is not there. This false detection is due to cross-reactivity with the urine drug tests.

Imposter substances for cannabinoids on urinalysis drug tests include cannabidiol (CBD) oil and other hemp products, HIV medications, ibuprofen, and other non-steroidal anti-inflammatory drugs, proton pump inhibitors, and baby wash products.

CBD is the second most prevalent active ingredient in marijuana. CBD is directly derived from hemp plants. Products made from hemp plants can have trace amounts of THC, even if THC is not on the label. Long-term regular use of CBD oil and other hemp products can build up enough THC in the body to test positive for marijuana and THC on urinalysis drug tests. Vitamin B supplements, like riboflavin, are made with hempseed oil and can also produce positive THC results. Despite the THC in the hemp plant, hemp products were legalized in 2018 under the Federal Farm Bill.

HIV and AIDS medications, like efavirenz and dronabinol, can produce positive urine drug tests for marijuana. Efavirenz is a potent antiretroviral medication used to treat HIV infections and dronabinol is used to treat loss of appetite and weight loss in people with HIV/AIDS. Dronabinol is also used to treat nausea and vomiting in chemotherapy patients. Dronabinol is classified as a cannabinoid because it is a synthetic THC that was legalized for medical use in 1985, which is why it can cause positive THC drug test results.

Pain medications, like ibuprofen and other non-steroidal anti-inflammatory drugs (NSAIDs), are over-the-counter medications that treat pain and fever. Ibuprofen medicines, like Motrin and Advil, and naproxen medications, like Aleve and Naprosyn, are NSAIDs that may produce positive THC results on urinalysis drug tests.

Proton pump inhibitors are used to treat heartburn symptoms and gastroesophageal reflux disease (GERD). Pantoporazole, a specific proton pump inhibitor medication, may cause positive drug test results for THC.

Commonly used infant and newborn soap products, like CVS Night-Time Baby Bath and Head-to-Toe Baby Wash, may cause THC-positive drug test results. Some health professionals speculate that positive THC drug test results are due to baby wash products containing ingredients with a chemical structure similar to THC.

Other discussions in future blogs.

In future blogs, I intend to discuss false positive drug results associated with poppy seeds, sleep aids, antidepressants, and other commonly used substances and medications.

If you haven’t read the first two installments of this blog series, click here for part one and here for part two! As stated above, Part 1 deals with substances that may cause a false positive for amphetamines. Part 2 deals with substances that may cause a false positive for cocaine.

Contact Experienced Health Law Attorneys in Matters Involving PRN or IPN.

The Health Law Firm’s attorneys routinely represent physicians, dentists, nurses, and other health professionals in matters involving PRN or IPN. Our attorneys also represent health providers in Department of Health investigations, before professional boards, in licensing matters, and in administrative hearings.

To contact The Health Law Firm, please call our office at (407) 331-6620 or toll-free at (888) 331-6620 and visit our website at


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Cotton, Steve, et al. “Unexpected interference of baby wash products with a cannabinoid (THC) immunoassay.” PubMed. (June 2012).

Gragnolati, Amy. “These 10 Medications Can Cause a False Positive on Drug Tests.” GoodRx Health. (14 July 2022).

Grinspoon, Peter. “Cannabidiol (CBD): What we know and what we don’t.” Harvard Health Publishing, (21 September 2021).

“Marijuana Legality by State.” DISA. (1 August 2023).

Olsson, Regan. “What Medications Can Cause False Positives on Drug Tests?” Banner Health. (7 January 2023).

O’Donnell, Brian, et al. “StatPearls: Dronabinol.” National Library of Medicine. 2023.

Rodriguez, Austin, et al. “Employer Drug-Testing Policies Must Evolve With State Law.” Law360. (19 July 2023).

Saltiman, Alec, et al. “False-Positive Interferences of Common Urine Drug Screen Immunoassays: A Review.” Journal of Analytical Toxicology, Volume 38, Issue 7. (September 2014) Pages 387-396,

“The Best Defense For Positive Drug Test.” Overland. (12 May 2023).

About the Authors: George F. Indest III, J.D., M.P.A., LL.M., is Board Certified by The Florida Bar in Health Law. He is the President and Managing Partner of The Health Law Firm, which has a national practice. Its main office is in the Orlando, Florida, area. The Health Law Firm, 1101 Douglas Avenue, Suite 1000, Altamonte Springs, FL 32714, Phone: (407) 331-6620; Toll-Free (888) 331-6620

Hartley Brooks is a law clerk at The Health Law Firm. She is preparing to attend law school.

Current Open Positions with The Health Law Firm. The Health Law Firm always seeks qualified individuals interested in health law. Its main office is in the Orlando, Florida, area. If you are a current member of The Florida Bar or a qualified professional who is interested, please forward a cover letter and resume to: [email protected] or fax them to (407) 331-3030.

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