An Introduction to CBD and Drug Testing

All states in the U.S. have laws legalizing cannabidiol (CBD) with varying degrees of restriction, but the federal government has a strict law making it illegal if the CBD product contains more than 0.3% tetrahydrocannabinol (THC), which is the psychoactive component of marijuana.1,2 Some states have legalized THC products, however, it is still considered a controlled substance federally and is considered illegal. Since CBD and THC come from the same plant, many speculate the possibility of a positive drug test result if only CBD is consumed. In this article, we will look to answer the question, “Does CBD show up on drug tests?”.

Basics of CBD and Drug Tests

The most common type of drug test used for employment or criminal justice reasons is a urine analysis due to its relatively low cost. This type of test allows for the detection of a variety of different chemicals that the body has been exposed to, but it does not give an accurate evaluation on the severity of intoxication or degree of exposure. One of the most common reasons for a drug test is to evaluate the use of marijuana.

There are two types of urine drug screens; an immunoassay or gas chromatography-mass spectrometry. The most common type of test is an immunoassay because it is relatively inexpensive. Gas chromatography-mass spectrometry tests are usually used to confirm the result of an immunoassay or to test a wider range of drugs because they are more expensive, and results take longer to receive. Urine drug screens use cut-off levels to help prevent false-positive results. This means the chemical being evaluated has to reach a certain level before the test is positive. Cut-off levels also reduce the risk of a person testing positive after passive exposure to a drug. Secondhand smoke is the most common example of passive exposure.4 The usual cut-off level for detection of marijuana in urine drug tests is 50 ng/mL, with 20 ng/mL being less common.

So, how does urine drug screens detect marijuana? An immunoassay is based on the principle of competitive binding. Chemicals that may be present in the urine compete against their related drug conjugate for binding sites on their specific antibody. During testing, a urine specimen moves upwards by capillary action. If a chemical is present in the urine below the cut-off level, it will not saturate the binding sites of its specific antibody. The antibody will then react with the conjugate and a colored line will be present in the desired test line region. If the chemical in the urine is above the cut-off level, then the opposite will happen, and no colored line will be present. In the sense of marijuana, the chemical being tested is a specific metabolite of THC, 9-carboxy-THC. This is one of the main inactive metabolites of the parent drug and is not a direct derivative of CBD. Other common drug screening methods, besides urine, that detect this metabolite and essentially an individual’s exposure to marijuana are hair, blood, and saliva tests.3

Do Drug Tests Detect CBD?

As mentioned earlier, the metabolite being assessed in drug tests is 9-carboxy-THC, which is not a metabolite of CBD. So, should one be worried about testing positive for marijuana if only CBD is being consumed? The answer ultimately depends on the CBD product and how much of that product is being consumed. Pure CBD will not show up on a drug test, but many commercial CBD products contain trace amounts of THC in them. In one study, acute administration of neither 100 mg of oral nor vaporized pure CBD produced positive urine toxicology results based on current U.S. drug testing guidelines. Only 1 of 218 specimens screened positive at 20 ng/mL after administration of pure CBD, but none at 50 ng/mL. This outlier was most likely due to limitations that occurred during the study. The study also showed that there were no indications that orally administered CBD was converted to 9-carboxy-THC. Another important finding that this study concluded was that inhaling vaporized CBD (not 100% pure) could potentially influence a positive drug test result.5 The main mechanism behind this is, in order for THC to be converted into 9-carboxy-THC, the metabolite evaluated in drug tests, it needs to be heated. Even though legal CBD products can only contain a minimal amount of THC (max of 0.3%), some of this product is being converted to 9-carboxy-THC. This might not show up on a drug test initially, but if continuously consumed the 9-carboxy-THC metabolite can accumulate within the body due to its long half-life, similar to CBD. This may result in a positive test result if enough of the metabolite has accumulated to reach past the test’s specific cut-off level.5

Overall, one should not be worried about testing positive for marijuana if the product they are consuming is 100% CBD. If there is even a slight percentage of THC in the product, there is a possibility for an individual to have an unexpectedly positive result for a drug test. It ultimately depends on the CBD product’s quality and composition, as well as how often the individual is using it.

References
  1. Devinsky O, Cilio MR, Cross H, et al. Cannabidiol: pharmacology and potential therapeutic role in epilepsy and other neuropsychiatric disorders. Epilepsia. 2014;55(6):791‐802. doi:10.1111/epi.12631
  2. Kogan NM, Mechoulam R. Cannabinoids in health and disease. Dialogues Clin Neurosci. 2007;9(4):413‐430.
  3. Raouf M, Bettinger JJ, Fudin J. A Practical Guide to Urine Drug Monitoring. Fed Pract. 2018;35(4):38‐44.
  4. Sissons B. Urine drug screen: Uses, procedure, detection times, and results. Medical News Today. https://www.medicalnewstoday.com/articles/323378#reliability. Published October 18, 2018. Accessed June 4, 2020.
  5. Spindle TR, Cone EJ, Kuntz D, et al. Urinary Pharmacokinetic Profile of Cannabinoids Following Administration of Vaporized and Oral Cannabidiol and Vaporized CBD-Dominant Cannabis. J Anal Toxicol. 2020;44(2):109‐125. doi:10.1093/jat/bkz080