Drug tests either test for the parent drug or at least one of its metabolites, or both. Concentrations of drugs in urine are usually higher than in blood and present for longer.
Federal workplace cutoff values for marijuana metabolites are 50 ng/mL for immunoassay screening tests (one ng is a billionth of a gram). In a confirmatory test, a metabolite of marijuana is measured, called delta-9-tetrahydrocannabinol-9-carboxylic acid, and a positive test result is above 15 ng/mL. However, this can vary depending on the variables listed above and should not be relied upon to ensure a drug-free result.
Drug testing can be conducted on various biological specimens, such as urine, hair, blood, saliva, sweat, toenails, fingernails, and meconium. Urine drug testing is the most common way of workplace testing for specific drugs because it is not invasive, and samples are easy to collect.
How much THC needs to be present to cause a positive drug test?
Several patient factors can also affect the result, such as body mass, urine pH, urine concentration and other medical conditions such as kidney or liver disease.
Medically reviewed by Carmen Fookes, BPharm. Last updated on Oct 30, 2019.
There are two main types of urine drug tests: screening and confirmatory tests. Immunoassay screening tests can be conducted on-site (point of care testing) or in a laboratory and allow large numbers of tests to be performed at once with relatively rapid results, providing an initial estimate of the presence or absence of drugs. There are three main types available, and all use antibodies to detect the presence of specific or classes of drug metabolites. Unfortunately, this can mean that substances with similar characteristics may be detected, resulting in false-positive results.
Some visual point of care tests are favored by pain management clinics or by clinicians treating people with substance misuse disorders. However, at times the results may be difficult to read (such as a faint color or an uncertain color) which can result in a subjective interpretation. These tests should only be considered preliminary and a follow up confirmatory laboratory test should be conducted, as with any screening test; however, this best practice may not always be followed.
If you are concerned that THC in your CBD oil or other CBD product may show up on a drug test, you may be able to reduce the chance of that occurring, though there is no guarantee. Some of the factors that may increase the likelihood of a failed drug test are:
THC can be detected in a urine test for up to 15 days, depending on how often and how much you use. It leaves the bloodstream in about five hours, but substances your body makes from THC (THC metabolites) can show up for as long as 7 days. CBD tends to stay in the bloodstream from 2 to 5 days, depending on dosage and frequency. If you have been using CBD for a while, it can stay in your body for up to 30 days or more.
Topical products that claim to contain CBD—like shampoos, cosmetics or creams—should not cause any reaction during a drug test because they do not enter the bloodstream. In the case of CBD oils, gummies, teas or transdermal patches, the situation is more complicated. In a test of 84 CBD products obtained online, 18 contained THC.
Factors in CBD Oil Showing on Drug Screen
CBD products can still be problematic, however, when it comes to drug testing. Though drug tests screen for THC, not CBD, many CBD products contain a trace amount of THC which will be detected in your bloodstream during a drug test.
CBD has taken off as a natural remedy for a variety of ailments. CBD products like CBD oil can be made from either the hemp plant or the cannabis plant, which are closely related varieties of the same cannabis species, Cannabis sativa. CBD products contain a cannabinoid—a chemical—called cannabidiol, which does not make you high. The substance in marijuana that causes a buzz is a different cannabinoid, called THC, or tetrahydrocannabinol.
The legality of CBD products can be confusing. CBD products made from certain cannabis plant varieties are legal only in states where marijuana is legal, due to the potential THC content. CBD products made from hemp variety plants are legal throughout the United States as long as they contain less than 0.3% of THC and do not make any medical claims. (A hemp plant is defined as Cannabis sativa that contains less than 0.3% THC.)
CBD will not show up in a drug test because drug tests are not screening for it. CBD products may well contain THC, however, so you can fail a drug test after taking CBD products. If you take CBD oil, you should plan accordingly if your work or activities require you to undergo drug testing.
CBD is one of many active chemical compounds in the cannabis plant. One reason it’s gaining momentum in popularity is because it is said to lack the component of the plant that causes a person to get high, which is called THC (tetrahydrocannabinol).
Some sources report that in rare cases, false positive test results have come from CBD oil that breaks down into very small amounts of THC in the stomach. Other studies, however, have refuted this.
Study of CBD Oil
The conclusion is that it’s still theoretically possible for traces of THC metabolites to be present in the stomach acid in the instance where “less-purified CBD productions” are ingested.
However, the distinction between full spectrum oils and isolates make all the difference if you are being tested for drug use.
A more likely secondhand exposure scenario is a positive marijuana hair test, resulting from direct contact with marijuana paraphernalia or from another person having THC on their hands.