Workplace Drug Testing BLOG

What You Need to Know About CBD and Drug Testing


Cannabidiol (CBD) does not show up on drug tests and should never lead to a positive drug test result for cannabis consumption. However, due to issues with cross contamination, sometimes CBD products can contain elements that will trigger a positive result.



Cannabis plants contain numerous compounds, including cannabinoids, terpenes, flavonoids and tetrahydrocannabinol (THC), the psychoactive element in cannabis that gives people the “high” feeling when they consume it.

The chemical makeup of a plant depends on the strain and variety.

Hemp plants are a type of cannabis plant that contain many of the same properties as cannabis, but only have trace amounts of THC. If someone tried to get high from smoking or eating products made from a hemp plant, it would not work.

CBD can be extracted from either regular cannabis plants or from hemp plants. It is usually extracted from hemp plants since they contain little to no THC and legally, CBD and other hemp products must contain less than 0.3% THC.

Since drug tests don’t screen for CBD, even if you have to undergo drug testing for work or some other reason, ingesting CBD should be no problem. You will not test positive for cannabis or THC if you are just ingesting CBD without also ingesting THC.

However, CBD hemp oil can also be extracted from regular cannabis plants and that’s where some of the trouble with CBD comes into play.


The Problem with CBD Products

The problem that consumers of CBD products are finding is that sometimes these products apparently have THC in them, as well. This means the consumer is unwittingly ingesting THC, which shows up on a drug test. For some people -- like commercial drivers and pilots, for example -- that means potential loss of a job if they test positive for THC.

So, how does THC contamination of CBD products occur?

CBD comes in three varieties:

  • Full spectrum
  • Broad spectrum
  • CBD isolate


Full spectrum

Full spectrum CBD means that the extract contains all of the elements that naturally occur in the plant it was derived from, including the aforementioned flavonoids, terpenes and other cannabinoids like THC.

If full spectrum CBD is extracted from a regular cannabis plant, which it often is, that means it will contain THC from the plant it was derived from.

On the other hand, if full spectrum CBD is extracted from a hemp plant, it is legally required to contain 0.3% or less of THC.

Since not all CBD product manufacturers reveal where their CBD comes from, it can be difficult to ascertain whether a product will contain more than trace amounts of THC.

Full spectrum products are widely available and include items like edibles, tinctures, topical creams and ointments.


Broad Spectrum CBD

Similar to full spectrum CBD, broad spectrum CBD contains other compounds found in cannabis plants. However, in broad spectrum CBD products, all of the THC has been removed. Therefore, it is much less likely for a broad spectrum CBD product to contain THC.

This type of CBD is less widely available and is often just sold as CBD oil.


CBD Isolate

As the name implies, CBD isolate is pure CBD that does not contain any other compounds of the plant it was derived from. It is generally extracted from hemp plants and should not contain any THC at all.

CBD isolate is available as an oil, tincture, crystalline powder or sometimes a solidified block.

To put it as simply as possible, because CBD is extracted from the same species of plant as THC, sometimes there is going to be cross contamination and sometimes that cross contamination will be enough to trigger a positive result on a drug test that screens for THC or one of its main metabolites, THC-COOH.


THC cutoff levels

Drug tests do not automatically return a positive result for any THC or metabolite detected. Rather, they have cutoff levels for the substance. If THC is detected, it must be above the cutoff threshold before it registers as a positive test.

Any amount of THC or THC-COOH detected below the cutoff level will be a negative test and any amount detected above the cutoff level will be a positive test.

Each type of drug test has its own cutoff levels, which we will look at below.



Urine testing is still the most common form of drug testing, especially for screening done in the workplace.

In urine testing, THC-COOH must be detected at a concentration of at least 50 nanograms per milliliter (ng/ml) to be considered a positive result. As an indication of how sensitive these tests are, a nanogram is approximately one-billionth of a gram.

Any amount of the THC metabolite below that cutoff level would be considered a negative result.

THC and its metabolites can be detected in urine generally within three to 15 days after consumption, but the detection window can be up to 30 days for heavy users.



Although not common for workplace testing, saliva is gaining popularity for drug testing because it is less invasive and much more convenient than urine testing. Currently, there are no cutoff limits for detecting THC in saliva, but a recommendation published in 2017 in the Journal of Medical Toxicology suggests a cutoff of 4 ng/ml.

THC can be detected in saliva for about three days, but that can be longer for heavy usage.



Hair testing is only common in certain industries, like casinos. There are no cutoff levels established for detecting THC metabolites in hair, but private industry cutoff levels of 1 picogram per milligram have been used. A picogram is approximately one-trillionth of a gram.

THC metabolites can be detected in hair for up to 90 days after consumption.



Blood is generally not used for workplace testing, but it might be used in the case of something like determining whether a person was under the influence while driving.

Aside from being extremely invasive, THC leaves the bloodstream after only five hours, although metabolites can be detected for up to seven days. In states with legal cannabis, the cutoff level for a blood test can be 1, 2 or 5 ng/ml. In states with no legalized cannabis, any amount over zero is considered to be a positive test result.


Other reasons CBD use might lead to a positive drug test result

There are any number of reasons why CBD usage might seem to lead to a positive drug test for THC, such as:



Whether it’s in the processing facility or even in your own home, the possibility for cross contamination is going to exist wherever CBD and THC co-exist.


Second hand THC

It’s highly unlikely, but not impossible to get a positive drug test by inhaling second hand cannabis smoke. There is some evidence to suggest that second hand smoke from particularly potent cannabis in a poorly ventilated area might lead to a positive drug test result.


Product mislabeling

Like health supplements, CBD products, such as cannabinoid oil, are not regulated and therefore there is no way to know for sure what is in them. A Dutch study in 2017 found that out of 84 products purchased online that claimed to contain only CBD, 21 of them also contained THC. These results suggest that mislabeling happens regularly in the industry.


Can CBD turn into THC in the human stomach?

Under the right acidic conditions, CBD can turn into THC, however there is no evidence that this transformation can occur in the human stomach, even though the stomach is acidic.


How do you guard against false THC positives if you’re taking CBD?

Because the industry is unregulated, it is difficult to know exactly what is in the product you are taking.

If possible, try to ascertain if the product was extracted from regular cannabis plants or THC-free hemp plants. Then, try to find out if it is full spectrum, broad spectrum or a CBD isolate.

Theoretically, this information should be easy to find. If it is not, that should be a red flag for you.

You should also try to choose products that list the concentration of CBD per dosage.

And, although it might take some homework, you should also try to find out where the hemp itself comes from for hemp-derived CBD products. Some states have more rigorous testing guidelines to make sure hemp is actually THC free.

There is no substitute for research. Read reviews of products to see what other people have experienced with the CBD product and read what you can find about the companies offering these products.

CBD will not trigger a positive drug test result for THC. If you have failed a drug test for THC after consuming a product that should have only contained CBD, it is likely that you ingested a cross contaminated product or somehow unknowingly ingested THC.

The only guaranteed way to avoid this type of potential cross contamination is to avoid consuming CBD products, but with a little research you can protect yourself from false positives for THC. If you are concerned that you may have ingested THC unwittingly, you can purchase a THC drug test and screen yourself to see what result you get.