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Can an Employee Fail a Drug Test if They Consume CBD?

Published on: March 2, 2020

Written by: Confirm BioSciences.

Medically Reviewed by: -

The increasing popularity of CBD has led to a changing reality of the meaning of “drug use” in the workplace. Multiple emerging medical studies have uncovered the benefits of cannabidiol (CBD), resulting in a global market of $4.6 billion in 2018.1

In January 2019, 7% of U.S. participants in a survey by Cowen Research reported that they use CBD as a supplement.2 Based on the analysis of the survey results, Cowen Research predicted a $16 billion consumer opportunity by 2025.2

More Pharma companies are showing interest in CBD because of its health benefits. Unfortunately, several manufacturers are making questionable medical claims and promoting CBD products with dodgy quality.3

The increasing consumption of CBD products has created a challenge when testing employees for drug use in the workplace.

CBD vs. THC: What is the difference?

Both CBD and tetrahydrocannabinol (THC) are members of the family of cannabinoids. The only difference between CBD and THC is in their chemical structure (Figure 1).


Figure 1. THC VS. CBD

A single cannabis plant can produce either CBD or THC because both compounds have the same precursor, CBGA. Now, whether CBGA becomes CBD or THC depends on the enzyme that acts on the precursor. If the enzyme that acts on the precursor is THCA synthase, then CBGA will be converted to THC; and if the enzyme that acts on the precursor is CBDA synthase, then CBGA will be converted to CBD.4

Does CBD Come from Hemp or Marijuana?

CBD can be derived either from the plant Cannabis sativa or Cannabis Indica. Hemp is Cannabis sativa L., and marijuana is either Cannabis sativa or Cannabis indica. Hence, CBD can come from either plant.

Hemp plants typically produce more of CBD while marijuana plants produce more of THC. Therefore, there is a significant difference between hemp-derived CBD and marijuana-derived CBD; the former contains less than 0.3% of THC and the latter contains 0.3% or more THC.5
Hemp-derived CBD is federally legal as far as it contains less than 0.3% THC, which poses fewer risks of side-effects and addiction. Unfortunately, the U.S. Food and Drug Administration (FDA) does not apply tight regulations to CBD products as it does to other drugs.

The problem is that, whether it comes from hemp or marijuana, CBD content is inconsistent. If it is not extracted properly, it could contain a higher percentage of THC, which can then show up on a drug test. Moreover, due to the minimal FDA regulations of CBD (except for the FDA-approved drug Epidiolex® for Lennox-Gastaut Syndrome), some hemp-derived CBD products end up containing a higher percentage of THC than 0.3%.

Does CBD Test Positive for THC in a Drug Test?

The short answer is, “No,” and that is only if we are talking about pure CBD (which has less than 0.3% of THC), and if it is consumed in small concentrations.

However, there have been cases where CBD oil users have failed a drug test due to positive THC results. The following are some reasons why CBD can test positive for THC in a drug test.

1. Varying Threshold Levels of Drug Tests Can Lead to Surprising Positive Results

Different types of drug tests vary in their thresholds for detecting THC.
Take, for instance, the traditional urine drug test. This test detects THC content only when the amount of THC is above 50 ng/mL. According to the National Institutes of Health (NIH) and the Substance Abuse and Mental Health Services Administration, the amount of THC in any individual should be below 50 ng/mL.6

So even if an employee has consumed a pure CBD product containing less than 0.3% of THC, if the amount of CBD consumed was more than 2,000 mg, the CBD content will exceed the cut off of 50 ng/mL, which will, in turn, produce a positive THC drug test result.
However, people rarely consume 2,000 mg of CBD product; this amount of CBD is higher than what the average consumer takes.6

2. Incorrect CBD Product Labels Can Confuse Consumers

Here is a second reason why CBD oil users can fail a drug test for THC: the CBD product labeling is sometimes not accurate.

Some CBD oils claim to be THC-free, but, as discussed earlier, there are minimal regulations for CBD and the product labeling is not always precise.

3. Certain Reagents Used in Drug Tests Can Convert CBD into THC

One study showed evidence that certain lab tests can produce identical positive results for THC and CBD.7 This can complicate your employee’s drug test and is something to watch out for.

In this study, a method called the gas chromatography-mass spectrometry (GC-MS) was used to analyze a sample. One disadvantage of using GC-MS for drug testing is that it cannot directly analyze drugs that are “nonvolatile, polar, or thermally labile,”8 which means that you need to add an agent to make the drugs easier to identify. Therefore, the GC-MS method requires that the lab technician adds a chemical to the sample before putting it in the machine. This process is known as derivatization.

In this study, perfluorinated anhydrides and perfluoroalcohols were used as the reagents. After the samples were run through the GC-MS machine, the results showed the same retention time and mass spectrum for the trifluoroacyl derivatives of THC and CBD.7 The explanation for this is that CBD is converted to THC under acidic conditions.

Note that if an employee has been consuming CBD solely and not THC, this test may report a false-positive test for THC.

The researchers of the study do not recommend these reagents to be used in drug tests as they may produce identical results for THC and CBD. To correctly identify THC in your employee’s drug test, make sure that the assigned lab is not using these reagents.

Many labs now use a more precise technique known as high-performance liquid chromatography to confirm drug tests. More optimized methods such as reversed-phase high-performance liquid chromatography (RP-HPLC) are more reliable and faster (with results within 10 minutes) for detecting eight different cannabinoids, including CBD. RP-HPLC uses acetonitrile and water as agents in a 1:1 ratio.9

However, labs that use GC-MS are still common as this method is considered the gold standard for broad-spectrum drug testing.

How to Address a Positive THC Test When an Employee Says it is Solely Due to CBD Use

Initial screening tests typically do not measure the quantity of the drug. However, confirmatory tests can correctly identify the specific drug and also find out how much of the metabolite is present.10

The first thing to do when an employee states that a failed drug test is solely due to CBD use is to confirm the result of the screening test by using a more sensitive method such as GC-MS or RP-HPLC.

Summary:

  • Several CBD products are marketed with questionable medical claims and undetermined quality as a result of minimal regulations by the Government.
  • One challenge for consumers is identifying how much THC is in their CBD product.
  • Another challenge is not knowing whether the CBD product is made from pure CBD or whether it is contaminated with higher amounts of THC.
  • Most CBD products are hemp-derived; hemp-derived CBD contains less than 0.3% of THC, which is federally legal, while marijuana-derived CBD contains 0.3% or more THC.
  • Although less than 0.3% of THC is legal, different types of drug tests still vary in their thresholds for detecting THC. For example, the traditional urine drug test detects THC content when the amount of THC is above 50 ng/mL.
  • Therefore, even though the chances of pure CBD with less than 0.3% of THC producing a positive THC result are slim, you can still get a positive THC result from a urine test if the amount of THC consumed exceeds 50 ng/mL.
  • CBD can also produce a positive THC test if certain reagents are used during GC-MS analyses. In one study, when perfluorinated anhydrides and perfluoroalcohols were used as reagents, the acidic base converted the CBD into THC, which led to a false-positive result for THC.
  • If an employee states that a failed drug test is solely due to CBD use, you can confirm this by using a more accurate method such as GC-MS or RP-HPLC.

References:

  1. Cannabidiol Market Size Analysis | CBD Industry Growth Report, 2025. https://www.grandviewresearch.com/industry-analysis/cannabidiol-cbd-market. Accessed February 28, 2020.
  2. Cowen’s Collective View of CBD. Cowen. https://www.cowen.com/insights/cowen-collective-view-of-cbd/. Accessed March 2, 2020.
  3. What You Need to Know (And What We’re Working to Find Out) About Products Containing Cannabis or Cannabis-derived Compounds, Including CBD. FDA. December 2019. http://www.fda.gov/consumers/consumer-updates/what-you-need-know-and-what-were-working-find-out-about-products-containing-cannabis-or-cannabis. Accessed March 2, 2020.
  4. 5.2_CBD.pdf. https://www.who.int/medicines/access/controlled-substances/5.2_CBD.pdf. Accessed March 2, 2020.
  5. Hilderbrand RL. Hemp & Cannabidiol: What is a Medicine? Mo Med. 2018;115(4):306-309.
  6. Kosecki D. Can CBD make you fail a drug test? CNET. https://www.cnet.com/news/can-cbd-make-you-fail-a-drug-test/. Accessed March 1, 2020.
  7. Andrews R, Paterson S. Production of Identical Retention Times and Mass Spectra for Δ9-Tetrahydrocannabinol and Cannabidiol Following Derivatization with Trifluoracetic Anhydride with 1,1,1,3,3,3-Hexafluoroisopropanol. J Anal Toxicol. 2012;36(1):61-65. doi:10.1093/jat/bkr017
  8. Kyle PB. Chapter 7 – Toxicology: GCMS. In: Nair H, Clarke W, eds. Mass Spectrometry for the Clinical Laboratory. San Diego: Academic Press; 2017:131-163. doi:10.1016/B978-0-12-800871-3.00007-9
  9. Zivovinovic S, Alder R, Allenspach MD, Steuer C. Determination of cannabinoids in Cannabis sativa L. samples for recreational, medical, and forensic purposes by reversed-phase liquid chromatography-ultraviolet detection. J Anal Sci Technol. 2018;9(1):27. doi:10.1186/s40543-018-0159-8
  10. Abuse S. Mental Health Services Administration: Clinical drug testing in primary care. Tech Assist Publ TAP. 2012;32.