Does CBD Cause Failed Drug Tests? 3 Risks & Precautions

It’s common for new users of CBD to worry about whether it will cause them to fail a drug test. This is particularly true due to the growth of the popularity of CBD, in addition to other cannabis-derived medications. As more people buy or are prescribed these products, knowledge of the risks of whether CBD shows up on drug tests is becoming more critical to obtain. For some, a drug test may be imminent as part of a pre-employment screening or court-ordered testing for substances. Many jobs will also conduct regular drug testing of employees within specific sectors, such as construction or mining. In addition, roadside drug testing is done around Australia, which screens for THC from cannabis in drivers. Learning the risks involved in taking CBD is crucial before you drive on it in Australia. The consequences for failing these drug tests can be substantial, with hefty fines and impacts to your employment or driving license on the line. Understanding the rules and precautions you can take to minimise or eliminate any risks is prudent if you’re using CBD when driving. 

What is CBD?

CBD is short for ‘cannabidiol’ and is one of the many cannabinoid compounds found in the cannabis sativa plant. These chemicals are known to have therapeutic properties and can provide pain-reducing, anxiety-relieving and anti-inflammatory effects. Among them, CBD is famous for reducing stress, lowering blood pressure and helping users sleep better. It is typically consumed in the form of CBD oil, which is extracted from the hemp plant and refined to be used as a health supplement or medication. 

How CBD Differs from THC

The catch with cannabis is that alongside therapeutic compounds like CBD, it also produces THC, a psychoactive cannabinoid that can be risky due to its mind-altering effects. Unlike CBD, THC is used for recreational purposes in addition to therapeutic applications. It is infamous in society due to its association with marijuana and the ‘high’ it causes. Due to its psychoactivity, THC can trigger adverse mental states like psychosis in those with mental illnesses. It is also illegal in most countries. In Australia, THC is only legal in some forms of prescription medication but otherwise banned for recreational purposes. 

Why THC Causes Impairment

Both CBD and THC act on cannabinoid receptors in the brain. But THC acts on them much more powerfully, which means it causes motor function impairment, cognitive slowing and reduced reaction time. These effects make THC dangerous for those who are driving. It intoxicates those who ingest it, which means using it after driving can increase the risk of accidents. Similar to alcohol, getting behind the wheel after taking THC is a high risk, and for this reason, it’s part of roadside drug testing protocols by police in Australia. It’s also part of most other drug testing protocols.

Drug Testing and Cannabinoids

In Australia, there are several scenarios in which you could be drug tested or screened for different substances. This includes:

  • Pre-employment drug screening: many employers screen new employees entering their workforce. In particular, jobs that require operating machinery, like aviation or mining, tend to be targeted for drug tests before an employee can begin working.
  • Athlete drug tests: in many sports at the professional level, drug testing for banned performance-enhancing drugs, in addition to THC or other substances, forms part of regular testing that athletes are subject to.
  • Regular workplace drug testing: alongside pre-employment screens, many jobs require drug tests to be done at random periodically to ensure employees are not impaired when working or at risk of intoxication when operating machines.
  • Roadside drug testing: is done across Australia in all states at random and screens for THC as part of its metabolite testing.
  • Security clearance drug testing is frequently performed in government or military jobs as a precautionary measure to prevent employees from sharing secrets when intoxicated.

Does CBD Show in a Drug Test?

Drug tests in Australia usually screen for specific metabolites in the urine or blood that will indicate whether a person has recently used the substances being checked for. The tests contain chemicals known as antibodies that react to these metabolites, enabling them to be measured. Common substances that are screened in drug testing include THC, amphetamines, cocaine, benzodiazepines, and more. 

Each of these substances has a different half-life in the body and must be screened for in differing ways. When it comes to cannabinoids, only THC is generally screened for because of its intoxicating effects, which impair motor function. Drug tests don’t screen for CBD as it has no impairment to cognition or reaction times. Having THC in your system when taking a drug test could mean you fail it and incur consequences. But CBD is safe to use when tested, provided your product is very high purity and contains no THC.

Urine Tests for THC

‘Almost all modern drug tests are seeking to understand whether you have metabolites of THC in your body, which indicates the use of marijuana. These metabolites are produced in the liver when the body breaks down THC. A routine urine drug screen for cannabis use consists of an immunoassay with antibodies that are made to detect the primary THC metabolite known as THC-COOH. The immunoassay screen is generally positive if more than 50ng/mL of the metabolite is found on the screen. Usually, a more sensitive follow-up repeat of the test is done to verify that a false positive hasn’t been made. Fortunately, urine drug screens for THC-COOH have low cross-reactivity to other cannabinoids that are not psychoactive, such as CBD (cannabidiol), CBG (cannabigerol), or CBN (cannabinol). This means pure products containing one of these cannabinoids won’t result in a false positive test, providing it has 0% THC. 

THC is Detectable for Long Periods

Less fortunately for those who have consumed THC, it will be detectable in urine drug screens for long after their last dose. THC is fat-soluble and has a long half-life in the body, meaning it can cause drug tests to fail even if you haven’t taken any in an extended period. Those who are daily users of cannabis containing THC or THC cannabis medications may still have it in their system for up to four weeks or more after they cease consumption. If you’ve only used it once or intermittently, it’s usually detectable for around three days after taking it. The duration of THC stays in your system is determined by how much THC you’ve consumed and how long ago. Factors including your body size or weight, individual physiology, age, and the dose you use can also influence this duration.

Will I Fail a Drug Test Using CBD?

Although CBD isn’t tested for directly on roadside, pre-employment or other drug tests, using it still carries some risk of failing drug tests. This is due to the potential for your CBD product to contain trace amounts of THC. Let’s run through a few scenarios where this risk could be present.

Incorrect Product Labelling

Labelling across many CBD products isn’t highly accurate when it comes to cannabinoid content and concentrations. In many cases, there may be levels of THC in a given product that are higher than advertised. This could be intentional or accidental. For example, some providers don’t test their products, which raises the risk that they contain THC. Others may be using subpar production methods for their CBD oil, which can lead to contamination with THC.

Full-Spectrum CBD With THC Traces

There are several types of CBD oil, which differ based on their cannabinoid and nutrient content. Full-spectrum CBD oil types carry the risk of containing THC, which could be found on a drug test. This type of oil is the least refined, enabling it to contain higher amounts of phytonutrients and minor cannabinoids like CBG. While these components add several unique benefits for users of full-spectrum CBD, the reduction in refinement means that the THC cannabinoid can be present in larger quantities. It can also contain the cannabinoid THC-A, which is not intoxicating but can increase TH-COOH metabolite levels. In Australia, these full-spectrum CBD products can hold up to 0.3% THC, which is enough to show up on drug tests if you’re taking a lot of CBD.

High CBD Doses

If you’re using a full-spectrum CBD product, consuming high doses of it regularly will substantially increase your risks of failing a drug test from THC presence. Individuals using huge doses of full-spectrum CBD oil, such as 1000mg or more per day, significantly increase their risk of failing drug tests. Not only does it raise the amount of THC being consumed, but other minor cannabinoids like THC-A can also pose an added risk because of cross-reactivity with immunoassays. An individual consuming 1000mg of full-spectrum CBD per day could be consuming up to 3mg of THC and THCA each day if it contains 0.3% of these cannabinoids. Over time, they can accumulate in the body, further exacerbating risks.

Precautions to Avoid Failing Drug Tests

Although using CBD carries some risks when it comes to drug tests for THC, there are several countermeasures you can take to mitigate or even eliminate this risk.

Understand What’s Tested

Checking up on the drug tests you may be subject to, how they are conducted, what they check for, and in what concentrations is the first step you should take to help protect yourself. Not all drug tests are the same. For example, older tests could use gas chromatography, which is less accurate and results in higher false positives than modern test protocols. Immunoassay screens from urine are more accurate and more sensitive to THC. Make sure you understand the testing regime you’ll be taking and the threshold quantities of THC in it that represent a positive test.

Avoiding THC Contamination

The primary risk involved in using CBD while being drug tested is cross-contamination from THC in your product. Many low-quality CBD products are often not free of THC. Some are produced using the same equipment that THC products are manufactured with, which causes contamination risk. Extraction methods used could also be sub-standard and mean not all THC is removed from the CBD extract when producing it. This can occur when solvent extraction is used, which has lower efficacy than supercritical CO2 extraction. You should steer clear of products not quality-assured or produced using solvent extraction.

Many of these products market themselves as extracted from ‘industrial hemp’ or hemp that contains low THC levels (generally less than 0.2% concentration in Australia). In reality, however, this is often untrue. Frequently, they’re produced from cannabis plants that contain greater than trace amounts of THC. The risk of this occurring is much higher if you buy your CBD from overseas, where regulations are less stringent.

Avoid Full-Spectrum CBD

Full-spectrum CBD oil will contain both THC and THCA in trace amounts, each of which raises the risks of failing a drug test. Using high quantities of the product adds to this risk. For this reason, it is recommended to avoid full-spectrum CBD product types and seek out CBD isolate. Isolate CBD products have much higher purity due to being more refined, making them safer for those being drug tested as THC quantities are eliminated. The downside is that isolate CBD has less of the beneficial antioxidants, phytonutrients, minor cannabinoids and terpenes that make full-spectrum CBD ideal for holistic wellbeing. But the added safety from reduced THC content is worth it for peace of mind. 

Obtain a Certificate of Analysis

The single best way to avoid accidentally consuming THC when you’re taking CBD is to obtain an independent laboratory analysis that confirms your product is 0% THC (or close to it). This is called a ‘Certificate of Analysis’ or COA for cannabis products, which will appear as a high-accuracy list of the product’s ingredients and cannabinoid quantities. Cannabinoids like THC and THCA will be shown on this list for you to identify and avoid. Avoid purchasing CBD from providers that don’t offer a COA, as you have no guarantee the product you’re buying contains no THC.

A COA also helps you avoid the risks associated with mislabelled CBD products. Many CBD retailers lie about their product formulation and state it contains no THC when this isn’t true. They may misconstrue the amount of THC in their product, which puts you at risk. Often, this is so the seller can sell more of their products, claiming they are purer than reality. The only way to ensure a product is not mislabelled or contaminated with THC is by getting third-party lab testing results.

Can I Still Take CBD?

Providing you take the necessary precautions, it should be safe to continue using CBD while being drug tested. Buying a high-quality CBD isolate that has been lab-tested and contains no THC will pose no risk of causing drug test failures. Even full-spectrum CBD products could be viable in some cases, providing they are not mislabelled and only contain 0.3% or less THC. You’ll need to add more caution, however, and calculate the amount of THC you’re potentially consuming, its threshold in drug tests you’re subject to and factor in the accumulation of the cannabinoid due to its fat solubility. Avoiding full-spectrum products as a precaution will be a more straightforward approach here for most.

Consequences for Getting it Wrong

Miscalculating the risks involved or not taking the appropriate precautions when using CBD could result in substantial detrimental consequences if you fail drug tests. If you’re being screened for a job or as part of regular employment, failing a test might mean losing your job or not getting hired. It can damage your career and mean you can’t get hired elsewhere.

Drivers are potentially the most at risk when it comes to being drug tested in Australia. The regulation in Australia has a zero-tolerance approach concerning the presence of THC in a driver’s system. If any amount of THC is detected in roadside drug testing, it’s considered to be driving under the influence. It doesn’t matter if your positive test while driving is a result of prescription medicine or mislabelled CBD products. Any presence of THC will mean you could be charged for driving while intoxicated. The consequences can involve significant fines, a loss of your driving license, criminal charges or bans from driving. This will still apply even if you are not impaired from THC or display any symptoms of motor function impediment. Tests only check whether its metabolites are present in your body, which can be present for days or weeks after exposure.


Can just CBD fail a drug test?

It’s important to know whether CBD can cause a positive result on drug tests if you’re using it and driving or if your employment depends on a clean result. Pure CBD, which is cannabidiol without any traces of THC, should not cause a positive result on a drug test. This rules out full-spectrum CBD products, which contain trace amounts of THC. Using high-quality isolate CBD products from reputable manufacturers that provide third-party lab testing to ensure the absence of THC is essential.

Does CBD Show Up on Drug Tests in Australia?

In Australia, drug testing typically focuses on detecting illicit substances that cause intoxication or motor skill impairment. They are not designed to test for the presence of CBD. However, the presence of small quantities of THC in some CBD products could potentially lead to a positive result on a drug test. To minimize the risk of testing positive, individuals using CBD in Australia should select isolate CBD products with low or no THC content.

What Drugs Show Up on Roadside Drug Tests?

Roadside drug tests in Australia aim to detect the presence of illicit drugs, such as cannabis (THC), methamphetamine, ecstasy (MDMA), and cocaine, using saliva samples. These are performed regularly across all states in Australia. Any presence of THC in a driver’s system is considered driving under the influence, regardless of how long ago the individual consumed THC.

Does Full-Spectrum CBD Contain THC?

Full-spectrum CBD products, which are derived from the whole cannabis plant, contain a range of cannabinoids, terpenes, and other naturally beneficial compounds. Some full-spectrum CBD products have trace levels of THC. In Australia, full-spectrum CBD oil must contain less than 0.3% THC, which is not enough to produce intoxicating effects. However, it’s crucial for individuals who undergo drug testing to be aware of the potential presence of THC in these products. Consuming high doses of full-spectrum CBD increases the risks of failing a drug test. The oil typically also contains THC-A, which has cross-reactivity with immunoassay tests and can cause false positives despite being non-intoxicating. If drug testing is a concern, opt for CBD isolate products that have been independently lab-tested.


In Australia, the use of CBD has several key risks for those who are being drug tested. Drug tests for employment, as part of regular screening for work or for drivers as part of roadside testing, will each screen for the presence of THC. These tests are sensitive and check for the TH-COOH metabolite in your body, which can remain for an extended period after consuming THC. Using CBD can cause risks of THC consumption if you take a low-quality or mislabelled product, consume full-spectrum CBD containing trace levels of THC or don’t obtain lab analysis on your product’s cannabinoid content. These risks can be easily avoided, however. Opt for isolate CBD and ensure you get lab results when buying. Taking measures to protect yourself and avoid any risk of a positive drug test is essential to prevent the negative consequences of THC ingestion, which could mean fines, loss of license or losing employment.