Cannabidiol (CBD) shouldn’t show up on a drug test.

However, many CBD products contain trace amounts of delta-9-tetrahydrocannabinol (THC), marijuana’s main active ingredient.

If enough THC is present, it will show up on a drug test.

This means that in rare cases, using CBD might lead to a positive drug test. It all depends on the product’s quality and composition.

Read on to learn how to avoid a positive drug test result, what to look for in CBD products, and more.

Most CBD products aren’t regulated by the Food and Drug Administration (FDA). As a result, it’s difficult to know what’s in them — even if these products are legal in your state.

Factors such as where the CBD extract comes from and how it’s harvested might make THC contamination more likely. Certain types of CBD are less likely to have THC in them than others.

CBD comes from cannabis, a family of plants. Cannabis plants contain hundreds of naturally occurring compounds, including:

  • cannabinoids
  • terpenes
  • flavonoids

Their chemical composition varies according to the plant strain and variety.

Although marijuana and hemp products are both derived from cannabis plants, they contain different levels of THC.

Marijuana plants typically contain THC in varying concentrations. The THC in marijuana is what produces the “high” associated with smoking or vaping weed.

In contrast, hemp-derived products are legally required to contain less than 0.3 percent THC content.

As a result, hemp-derived CBD is less likely to contain THC than marijuana-derived CBD.

Plant variety isn’t the only factor. Harvesting and refinement techniques can also change which compounds appear in CBD.

CBD extracts are typically labelled as one of the following types.

Full-spectrum CBD

Full-spectrum CBD extracts contain all of the compounds that occur naturally in the plant they were extracted from.

In other words, full-spectrum products include CBD alongside terpenes, flavonoids, and other cannabinoids such as THC.

Full-spectrum CBD products are typically extracted from the marijuana subspecies.

Full-spectrum marijuana-derived CBD oil may contain varying amounts of THC.

Full-spectrum hemp-derived CBD oil, on the other hand, is legally required to contain less than 0.3 percent THC.

Not all manufacturers disclose where their full-spectrum extracts come from, so it can be difficult to assess just how much THC may be present in a given product.

Full-spectrum CBD is widely available. Products range from oils, tinctures, and edibles, to topical creams and serums.

Broad-spectrum CBD

Like full-spectrum CBD products, broad-spectrum CBD products contain additional compounds found in the plant, including terpenes and other cannabinoids.

However, in the case of broad-spectrum CBD, all of the THC is removed.

Because of this, broad-spectrum CBD products are less likely to contain THC than full-spectrum CBD products.

This type of CBD is less widely available. It’s most often sold as an oil.

CBD isolate

CBD isolate is pure CBD. It doesn’t contain additional compounds from the plant it was extracted from.

CBD isolate typically comes from hemp plants. Hemp-based CBD isolates shouldn’t contain THC.

This type of CBD is sometimes sold as a crystalline powder or a small, solid “slab” that can be broken apart and eaten. It’s also available as an oil or tincture.

Drug tests screen for THC or one of its main metabolites, THC-COOH.

According to Mayo Clinic Proceedings from 2017, federal workplace drug testing cut-off values were established to avoid the possibility that trace amounts of THC or THC-COOH would trigger a positive test.

In other words, passing a drug test doesn’t mean that there isn’t any THC or THC-COOH present in your system.

Instead, a negative drug test indicates that the amount of THC or THC-COOH is below the cut-off value.

Different testing methods have different cut-off values and detection windows, as listed below.

Urine

Urine testing for cannabis is common, especially in the workplace.

In urine, THC-COOH must be present at a concentration of 50 nanograms per milliliter (ng/mL) to trigger a positive test. (A nanogram is approximately one-billionth of a gram.)

Detection windows vary a lot according to dose and frequency of use. In general, THC metabolites are detectable in urine for approximately 3 to 15 days after use.

But heavier, more frequent cannabis use can lead to longer detection windows — more than 30 days, in some cases.

Blood

Blood tests are far less common than urine tests for drug screening, so they’re unlikely to be used for workplace testing. This is because THC is quickly eliminated from the bloodstream.

It’s only detectable in plasma for up to five hours, though THC metabolites are detectable for up to seven days.

Blood tests are most often used to indicate current impairment, for instance, in cases of driving under the influence.

In states where cannabis is legal, a THC blood concentration of 1, 2, or 5 ng/mL suggests impairment. Other states have zero-tolerance policies.

Saliva

Currently, saliva testing isn’t common, and there are no established cut-off limits for detecting THC in saliva.

A set of 2017 recommendations published in the Journal of Medical Toxicology suggest a cut-off value of 4 ng/mL.

THC is detectable in oral fluids for around 72 hours, but may be detectable for much longer with chronic, heavy use.

Hair

Hair testing isn’t common, and there are currently no established cut-off limits for THC metabolites in hair.

Private industry cut-offs include 1 picogram per milligram (pg/mg) of THC-COOH. (A picogram is about one-trillionth of a gram.)

THC metabolites are detectable in hair for up to 90 days.

There are several potential reasons why CBD use might lead to a positive drug test result.

Cross-contamination

There is potential for cross-contamination during the CBD manufacturing process, even when THC is present only in trace amounts.

Cross-contamination may be more likely for manufacturers preparing products that contain CBD only, THC only, or a combination of the two.

The same is true in stores and at home. If CBD oil is around other substances that contain THC, cross-contamination is always a possibility.

Secondhand exposure to THC

Although it’s unlikely that you’ll receive a positive drug test result after exposure to secondhand marijuana smoke, it’s possible.

Some research suggests that how much THC you absorb through secondhand smoke depends on the potency of the marijuana, as well as the size and ventilation of the area.

Product mislabeling

CBD products aren’t consistently regulated, which means that there typically isn’t a third party testing their actual composition.

A 2017 study from the Netherlands evaluated the accuracy of the labels provided on 84 CBD-only products purchased online. The researchers detected THC in 21 of the products tested.

This suggests that product mislabeling is fairly common in the industry, although more research needs to be done to confirm if this is also true for American CBD products.

In acidic conditions, CBD can turn into THC.

Some sources speculate that this chemical transformation also occurs in the human stomach, an acidic environment.

In particular, a 2016 in-vitro study concluded that simulated gastric fluid can transform CBD into THC.

However, a 2017 review concluded that in-vitro conditions don’t represent the actual conditions in a human stomach, where a similar transformation doesn’t appear to occur.

The researchers in the 2017 review also pointed out that among the reliable clinical studies available, none have reported side effects of CBD similar to those associated with THC.

Some CBD products may be safer than others. If you’re considering using CBD, it’s important to take time to evaluate the products available.

Read the product information

Find out whether the product comes from hemp or marijuana. Next, find out whether the CBD is full-spectrum, broad-spectrum, or pure CBD isolate.

Remember that CBD products that come from marijuana, along with full-spectrum CBD products derived from hemp, are more likely to contain THC.

This information should be very easy to find. If it’s missing from the product description, it might be a sign of a not-so-reliable manufacturer.

Opt for products that list the amount of CBD

It’s a good idea to find out the concentration of CBD per dose.

Remember that it may vary according to whether the product is an oil, tincture, edible, and so on.

In many cases, more concentrated CBD products are more expensive, even though they may appear to be the same size or smaller than other products.

If possible, start with a low-dose product.

Find out where hemp-derived CBD products come from

Hemp quality varies by state. More reputable states, such as Colorado and Oregon, have longstanding hemp industries and rigorous testing guidelines. If information about the hemp isn’t available on the product description, contact the seller.

Do your research

When evaluating the product, you should look for certain terms, such as:

  • USDA-certified organic
  • CO2-extracted
  • solvent-free
  • decarboxylated
  • pesticide- or herbicide-free
  • no additives
  • no preservatives
  • solvent-free
  • lab-tested

However, in many cases it will be difficult to prove that these claims are true. The best way is to look for any available lab test results associated with a given manufacturer.

Avoid products that make health-related claims

CBD isn’t a prescription drug. It hasn’t undergone FDA testing to assess its safety and effectiveness in treating specific health problems, such as anxiety or headaches.

Therefore, sellers aren’t allowed to make health-related claims about CBD. Those that do are breaking the law.

Routine drug tests don’t screen for CBD. Instead, they typically detect THC or one of its metabolites.

The person ordering the drug test could request to have CBD added to the list of substances being screened for. However, this is unlikely, especially in states where CBD is legal.

CBD shouldn’t show up on a routine drug test.

However, keep in mind that the industry isn’t consistently regulated, and it’s hard to know what you’re getting when you purchase a CBD product.

If you want to avoid THC, ensure that you’re purchasing CBD isolate from a reliable source.