Will I Fail a Drug Test Using CBD Oil in Australia?

Its important to understand the risks involved in using CBD – will it cause you to fail a drug test? Many jobs in Australia either require drug tests to be completed to start in a role, or may be regularly screened as part of regular drug testing ongoingly. These are typically trade related roles where operating or working nearby heavy machinery, vehicles and hazardous environments are commonplace. The other commonly encountered drug test is Roadside Drug Testing or ‘RDT’ in Australia which is performed regularly in many Australian states like NSW and Queensland. These tests are done at random on many main roads, particularly after events or on long weekends. They are designed to screen for intoxicated drivers who are drug affected. However both of these tests can result in positives for those using CBD oil either by prescription or online. If this is you and you’re worried about using CBD due to concerns over failing a drug test – you likely needn’t. Let’s have a look at whether or not CBD will cause you to fail a drug test and why. There is always a risk of failing your testing but you can mitigate this risk.

How Drug Testing Works

Drug tests in Australia usually screen for certain metabolites in the urine or blood that will indicate whether or not a person has recently used a substance being screened for. The tests contain substances known as antigens which will bind with and react to these metabolites. Common substances that are screened in employee or roadside drug testing include THC, amphetamines, cocaine, benzodiazepines and more. Each of these substances has a different half life in the body and as such, must be screened for in differing ways. Drug tests almost never screen for CBD or cannabidiol. Generally only THC or tetracannahydrol will be displayed in a screening, as this is the psychoactive substance responsible for the intoxicating ‘high’ cannabis causes. 

A routine urine drug screen for cannabis use consists of an immunoassay with antibodies that are made to detect its main metabolite, 11-nor-delta9-carboxy THC (THC-COOH). The cut-off level for a positive urine screen in the immunoassay at 50 ng/mL. When the immunoassay screen is positive at the > 50 ng/mL level, a test is performed to verify the positive urine screen. The confirmatory GC/MS has a cut-off level of 15 ng/mL and is specific only to the 11-nor-THC COOH metabolite. Fortunately, the urine drug screen for THC-COOH is known to have very little cross reactivity to other cannabinoids that are not psychoactive, such as CBD (cannabidiol), CBG (cannabigerol), CBN (cannabinol). 

Individuals using unusually large doses of a cannabinoid-rich CBD oil product (above 1000-2000 mg of CBD oil daily) could theoretically test positive during the initial urinary screen. The urine screen in these cases would likely represent a “false positive” due to other non-THC metabolites or compounds, which may cross-react with the immunoassay. Keep in mind that most of the high-quality CBD oil products contain less than 0.2% THC. An individual consuming 1000-2000 mg per day of CBD oil would thus consume about 3-6 mg of THC-A. THC-A is the compound found in Cannabis prior to being decarboxylated and does not get you high. 

Exceedingly high doses may result in detection of positive urine screens in up to 10% to 20% of assays. Most research suggests that for infrequent or ‘non-daily’ users of cannabis, a typical high-dose marijuana cigarette (containing about 40mg to 50mg of THC) would result in a positive THC metabolite screen for up to two days at this cut-off level. This depends on many factors including: How much & how often cannabis is used, the metabolism of each individual, route of administration and other factors such as medications used, liver or kidney disease. If you have any concern about testing positive for THC when using CBD oil please seek advice from your health care professional. 

THC Contamination Risk

The real risk inherited by using CBD oil or similar CBD products like strips, gels or capsules is THC contamination. The issue with many CBD products is they are often either not entirely free of THC or were produced in vat or location where THC was also present, which causes contamination risk of the end product. Each of these scenarios is a little different but can cause a failed drug test result from CBD oil use. Many CBD products market themselves as produced from ‘industrial hemp’ or hemp that contains very low THC (generally less than 0.2% concentration). In reality however, this is often untrue – particularly for full spectrum CBD oils. THC often makes it way through the refining process and into the final oil. This particularly occurs when alcohol is used as a solvent as less purity is possible due to it being an inferior solvent versus CO2 or gas extraction which is better at THC removal. 

Even if this type of contamination doesn’t occur and the product is pure, a retailer may simply lie about their formulation. This could mean THC is included in the product but not mentioned – often so the seller can make a sale. The only way you can be sure a product is not contaminated is getting a hold of third party lab testing results which will break down the active ingredients in the product, as well as purity and cannabinoid content. Retailers may have cut corners on labeling and forget to mention the THC content of their product, or glaze over this in warnings. They may also mislabel an isolated CBD product or 0% THC product as full spectrum CBD oil or vice versa. Full spectrum carries much higher risk of containing more than trace levels of THC due to being less refined. It will generally have all the cannabinoids present in the oil, which includes THC even at trace levels.

What is CBD?

CBD is a three letter abbreviation for ‘cannabidiol’ – one of hundreds of different cannabinoid compounds that you can find in the cannabis sativa plant. Many of these chemicals are therapeutic, offering anti-inflammatory and anxiety relieving effects. CBD in particular is well known for its highly beneficial ability to calm stress, lower blood pressure and help patients sleep. It’s mainly found and consumed as CBD oil, a hemp extract that is taken from the hemp plant and refined for use as a health promoting supplement or medicine. The challenge with cannabis is it also produces psychoactive chemicals known as THC. THC can be risky due to being able to trigger underlying mental conditions in the mentally ill. It also creates the high effect from cannabis and is illegal in most countries, including Australia. This is the compound that can make drug testing challenging with CBD.

Many other cannabinoids are found in hemp and are typically present in full spectrum CBD oil. These include CBN, CBG and CBDA and more. Each has differing effects and benefits for users. All are entirely natural and found in plants. Where a cannabis plant contains less than 0.2% THC it is generally classified as ‘industrial hemp’ which is used for commercial purposes such as medicines, many woven goods, clothes and more. In Australia the TGA regulates the use and breeding of these plants for medicinal purposes which includes CBD oil production.

How do CBD and THC work?

Both of these therapeutic cannabinoids act on our cannabinoid receptors. A system of receptors across the body is able to use and absorb cannabinoid compounds readily. This system is known as the endocannabinoid system, composed of CB1 and CB2 receptor types. When activated these release potent anti inflammatory endocannabinoids. Cannabinoids like THC can also interact directly with our serotonin or dopamine receptors in the brain. This is what gives cannabis the potential for psychological addiction as well as many of the mental issues THC can exacerbate. Serotonin affects mood, focus and stress or anxiety levels. THC is thought to impact our mood if dosed too frequently.

On the other hand as CBD only activates the endocannabinoid system it has no psychoactive effects or issues. It is used to reduce inflammation, pain, control anxiety or stress, help with sleep or insomnia plus aid in recovery and joint aches. CBD has both mental and physical benefits for users, helping many to find calmness, relax and reduce stress causing cortisol in the body.

Drug Testing and CBD in Australia

Whether you use a drug test involving a urine or blood screen, either will involve a metabolite test. Cannabinoids have certain metabolic markers which they leave in the body as evidence of use. Many cannabinoids can be detected in testing of the body’s lipids or urine and detected in trace levels. Depending on the precision of the test, these will typically only show a positive for a fairly large quantity detected. Most casual or intermittent cannabis users will not test positive. Chronic usage however will lead to accumulation of cannabinoids like THC in the lipids and body. Cannabinoids have a long half life to metabolize compared to many chemicals and are highly bioavailable. They’re stored in the body’s fats and can take weeks to move out of the body if consumed at high frequency.

When testing for THC in the blood, false negatives or positives are certainly possible. Testing equipment can be very inaccurate and often multiple tests or follow ups are done to validate an initial positive result. Generally THC can be detected after use for 3 days for single uses or if chronically used, after more than even 30 days due to THC being fat soluble. Its half life on average is typically longer than 4 days even from one time use. The time it takes to exit the body depends on a range of factors including your body size or weight, individual physiology, age, dosage time and amount. Many CBD-based oils will still contain some level of THC even if not explicitly advertised. Drugs approved by the TGA in Australia under schedule 4 will typically contain 0% THC due to the stringent license and testing requirements involved.

Avoiding THC

The most simple way to avoid a negative drug test is not taking any THC or alternatively, never driving or working a job requiring mandatory testing. Always shop around and research your product before you buy CBD. Check the product is organic, has lab results or a purity report available from third party sources, has adequate customer reviews and ideally is tested by you. This still can’t always guarantee you won’t be ingesting any THC but it can help to mitigate the risk. It’s important to note that it doesn’t matter the reason – if you have THC in your body you’ll fail a drug test. Whether this is a roadside drug test for driving in Australia, employment screening or just a regular test, the risks of consuming any hemp product will always exist. This will inevitably be treated as a driving under the influence or DUI case if you test positive while driving, which is always a risk in Australia – whether you’re located in Victoria, Queensland, New South Wales or elsewhere. Even if you have a prescription – you won’t be spared from the law. Medical cannabis in Australia is still treated under a blanket approach with regards to driving and drug testing legislation. It doesn’t matter if your positive test is a result of your prescription medicine or not – you’ll still be charged for driving while intoxicated and get a criminal record. Don’t risk it. Use public transport or alternative transport means if you need to.

Can I Work or Drive while using CBD?

The answer for most individuals is generally yes. From an effects standpoint, the largest risk or side effect to be mindful of with CBD is drowsiness. This can of course be problematic for those operating machinery, driving or performing delicate or sensitive tasks. However it’s a rare side effect – it typically only occurs at very high dosages for those who are sensitive to cannabidiol’s effects. CBD is non psychoactive and won’t cause an intoxicating high. Working or driving in the CBD should otherwise pose no risk. You’re only at risk if you have inadvertently consumed THC which can impair your motor skills and result in high risk if driving. THC can also cause you to lose focus as you will be intoxicated.


You won’t be screened in drug tests for CBD or other non psychoactive cannabinoids like CBG or CBN. These tests are looking for THC in your system in Australia. However, THC can be hard to avoid sometimes. Many manufacturers of CBD mislabel or mislabel their products. This can lead to THC in the final oil or confusion with the buyer and accidentally purchasing products that contain THC. They may also simply have THC in their product due to contamination – either knowingly or not. Unfortunately, THC is easily detectable even for casual marijuana users. It is fat soluble and stays in the body for long periods, especially where cannabis use is frequent and at high dosages. This causes a build up of metabolites in the body. Always understand what you will be tested for and ensure you do not risk using CBD products if it poses risk to you.