Drug tests identify tetrahydrocannabinol (THC) or its metabolites. Although these tests do not screen for CBD, some CBD products contain low quantities of THC that could theoretically make a person fail a drug test.
CBD products derive from hemp, a federally legal low-THC type of cannabis. While some CBD products claim to contain no THC, contamination may have occurred during the manufacturing process. In some cases, the manufacturer’s labeling may be incomplete.
Keep reading to learn whether CBD shows up on a drug test.
Cannabis sativa is an extremely versatile plant that growers cultivate for numerous purposes, ranging from food, such as hemp seed, hemp-based construction materials, and medicinal and recreational uses.
Researchers have identified over 400 chemical compounds in the cannabis plant, of which about 80 are biologically active.
The most important biologically active compounds in cannabis are cannabinoids. These compounds are specific to the cannabis plant and appear nowhere else in nature.
Some of the more abundant cannabinoids include THC, CBD, cannabigerol (CBG), cannabinol (CBN), and cannabichromene (CBC).
THC is the primary psychoactive compound in cannabis and is intoxicating. CBD does have some psychoactive effects, which is why researchers are studying its potential in treating mental health conditions, such as depression and anxiety. However, it does not have the same intoxicating properties as THC.
THC binds to receptors in different parts of the brain. These receptors normally attach to the endocannabinoids, which are natural compounds that the human body produces.
The following table lists areas in the brain that THC targets and its effects:
|Hippocampus||impairs short-term memory|
|Neocortex||impairs judgment and sensations|
|Basal ganglia||alters reaction time and movements|
|Nucleus accumbens||causes euphoria|
|Amygdala||causes panic and paranoia|
|Cerebellum||causes a feeling of being drunk|
|Brainstem||controls nausea and vomiting|
|Spinal cord||reduces pain|
CBD does not seem to bind to the same receptors as THC.
Scientists are still unsure how CBD exerts its effects, but they think it might boost endocannabinoid levels or bind to serotonin receptors. Serotonin is a hormone that regulates mood, happiness, and anxiety.
In animal and preliminary human studies, CBD has demonstrated some potential therapeutic effects, including:
- reducing inflammation
- relieving pain
- controlling anxiety
- controlling psychosis
- promoting neuroprotection
- preventing vomiting
The urine test is the most common diagnostic test for cannabis. The urine drug screen is an “immunoassay test,” which uses antibodies designed to latch on to specific drugs or their metabolites — in this case, the presence of THC and its metabolites.
If the antibodies identify a drug, they will produce a signal that shows the test as “positive.”
According to an article in American Family Physician (AAFP), the federal government sets drug concentration levels for urine drug screening.
If a test detects a drug under this concentration threshold, it will return a negative result. If a person tests positive on the screening test, they may have to undergo a follow-up test.
Confirmatory tests, such as gas chromatography and mass spectroscopy or high-performance liquid chromatography, are more accurate in detecting drugs and their metabolites.
Doctors must take great care when analyzing the results of a positive cannabis test since false-positive and false-negative results are possible.
People who unexpectedly test positive on a urine drug screen should speak with their doctor.
This occurs because THC is soluble in fat the body stores it in the fat compartments of the body. As a person burns or recycles this fat, it slowly releases the THC, and the kidneys eliminate it and its metabolites.
Researchers are also interested in using breath and saliva tests to detect cannabis in certain situations outside of the laboratory.
In theory, traffic police could use breath tests to check for impaired driving on the road. However, this technology is new and not yet fully understood.
Theoretically, people can fail a drug test if they consume a CBD product that also contains THC.
CBD-rich products derive from cannabis or hemp, both of which contain the full spectrum of cannabinoids, including THC.
In a 2019 analysis of 67 CBD-containing food products in Germany, researchers found that 25% of the samples contained THC above the 2.5 milligrams-per-day dose associated with intoxicating side effects.
Although manufacturers may state that they eliminate the THC from their products, this may not be the case. Sometimes, the product has not been third-party tested or is inappropriately labeled, misrepresenting the actual THC dose.
People can also receive a false-positive result for cannabis or THC on a urine drug screen if they use other drugs, including:
- nonsteroidal anti-inflammatory drugs (NSAIDs), such as ibuprofen, naproxen, and sulindac
One study in the Journal of Analytical Toxicology demonstrated that people exposed to passive, or second-hand cannabis smoke, can test positive on a saliva drug test.
Cannabis-free volunteers sat in an unventilated room for several hours with five people who each smoked one cannabis cigarette.
The researchers detected THC in the saliva of each of the cannabis-free volunteers, but these amounts declined over the time spent in the room. Researchers do not know whether exposure to second-hand cannabis smoke will produce a positive saliva test outside of the study environment.
An older study tested whether second-hand cannabis smoke can result in a positive urine drug screen.
The researchers collected 80 urine samples 24 hours after they exposed cannabis-free participants to second-hand cannabis smoke. Only two samples tested positive, but none tested at or above federal thresholds.
Drug tests do not screen for CBD because it does not cause intoxicating effects and is not an illegal controlled substance. Nevertheless, people who use CBD may still fail a drug test. Products that contain CBD may be contaminated with THC or have improper labeling.
Other drugs may interfere with urine drug screen results and result in a false-positive test. People who want to avoid testing positive for THC on a drug test should purchase CBD products from reliable sources that can confirm the product does not contain any THC.