THC Drug Test: An Overview

thc drug test

As certain cannabis and hemp products become legalized, confusion over terminology grows increasingly prevalent.

Questions of the differences between THC and CBD arise. Are they the same substance? Do both incite the same feelings? Can both be discovered on a drug test?

While THC and CBD are chemically identical, both compounds affect the body differently – and only one tends to appear on drug tests.

Follow along to uncover how THC drug tests work and explore the primary differences between THC and CBD.

How Does the THC Drug Test Work?

As the name implies, THC drug tests measure the presence of THC in the body through urinary, saliva, hair, or blood samples.

Most THC urine tests are designed to identify commonly excreted metabolites in THC consumers. If the concentration of THC in the body is greater than 50 ng/mL, the test will return positive.

THC urine tests are based on the competitive binding principle. Looking past the technical terminology, the competitive binding principle is fairly self-explanatory!

Simply speaking, drugs within a urine specimen compete for a binding site on their respective antibody with a specific conjugate. If the drug in the specimen is below the cut-off value – often 50 ng/mL – the competing conjugate will bind with the antibody, producing a visual result on the test. For many tests, this looks like a colored line.

How long is THC stored in the body?

THC is detectable longer than many other recreational substances because THC is a lipophilic cannabinoid. This simply means that THC is a fat-soluble compound stored in body fat.

However, various factors impact how long THC can produce a positive test, including method/ frequency of consumption and the type of THC test given. Metabolism and body fat also plays a case-by-case role.

Generally speaking, based on method/ frequency of consumption:

  • For infrequent consumers, traces can last for up to 3 days
  • For consistent/ heavy consumers, traces can last for up to 15 days
  • For chronic consumers, traces can last for up to 60 days
  • When THC is ingested, traces can last for 1 to 5 days

What is the Difference Between CBD and THC?

“CBD” and “THC” are often used interchangeably to refer to the same substance. However, these terns are not exchangeable, and – with the rise of certain legal cannabis products – distinguishing between each is important for consumers and business owners alike.

Cannabidiol (CBD) is one of nearly 480 naturally occurring compounds in Cannabis genus plants (including cannabis and hemp). A few other prominent compounds include terpenes, flavonoids, and delta-9-tetrahydrocannabinol (THC). Depending on the variety of cannabis, these compounds may vary in chemical composition.

Though CBD and THC both naturally occur in cannabis and interact with the body’s endocannabinoid system, THC is psychoactive. This means that THC provides the “high,” euphoric sensation associated with Marijuana consumption, while CBD doesn’t.

Three other differences between CBD and THC include chemical structure, legality, and side effects.


Currently, 44 states have legalized the use of marijuana for medical or recreational purposes. 13 states allow some CBD or minimal THC in products, and 4 states have no public cannabis programs.

Although marijuana consumption in some form is legal in some states, many employers still utilize pre-employment screening to determine eligibility. Though marijuana use is illegal under federal law, state marijuana laws differ widely, and every employer must consider the changing legal landscape.

Chemical structure

Interestingly, CBD and THC both have 2 oxygen atoms, 30 hydrogen atoms, and 21 carbon atoms – the same molecular structure. Both substances also affect the release of neurotransmitter chemicals in the brain, including stress and immune function.

If CBD and THC possess the exact same molecular structure, what makes them chemically different? The only difference is a slight variation in how the atoms are arranged.

This variation, however minimal, accounts for a significant difference in the effect on the body, explored below:

Psychoactive elements

As previously mentioned, THC is the psychoactive component of cannabis that produces the “high” feeling. Though CBD is technically psychoactive as well, it does not bind with the cannabinoid 1 receptors in the brain that induce a euphoric sensation. CBD must be bound with THC to provoke this result.

Side effects

In general, CBD is viewed as tolerable to the body. Side effects stemming from CBD consumption often have to do with an unprecedented drug-to-drug interaction between CBD and another substance.

THC can cause temporary and long-term side effects. Temporary effects may include:

  • increased heart rate
  • memory loss
  • anxiety
  • red eyes
  • coordination difficult
  • dry mouth

Long-term usage of large amounts of THC could lead to negative psychiatric effects.

Does CBD cause a positive THC drug test results?

Firstly, CBD often will not appear on a drug test. However, elements of THC are sometimes be found in substances with CBD. Even self-proclaimed “THC-free” products may contain trace amounts of THC.

Even though CBD products are legal in multiple states, they are not regulated by the Food and Drug Administration (FDA). Thus, precise ingredients are often difficult to identify. Amounts of THC in CBD products depend on factors such as product composition and where the CBD was harvested.

Full-spectrum CBD products include other cannabinoids. For example, full-spectrum marijuana-derived CBD products often include THC, while full-spectrum hemp-derived products may legally contain less than 0.3 percent. If a manufacturer does not disclose where the full-spectrum product was derived from, the consumer can only guess how much THC may be present in the item.

Thus, to avoid a positive THC drug test, it is safest to eliminate consumption of CBD products, even supposedly “THC-free” items.

Rapid Detect: Meeting Your Testing Needs

At Rapid Detect, we can meet your business testing needs, regardless of industry or locale. Our high-quality, low-cost products and one-on-one customer service are designed to give our customers an edge in their industry.

Our selection of urine drug test kits is designed to produce fast, accurate results. To learn more about how we could serve your business, please drop us a line at 888.404.0020 or complete our contact form! A specialist will be in touch shortly.