According to Robert Fitzgerald, a professor at the University of California, San Diego’s Center for Advanced Laboratory Medicine, “It would depend on the purity of the product.”
A false-positive on a drug test could have implications for people at work, and in their medical care. For example, some health care organizations do not allow patients to start opioid painkillers if they use marijuana.
While the findings may be a relief to some CBD users, there is a big caveat: The researchers used pure CBD. In the real world, CBD products are largely unregulated and may contain other compounds due to processing.
CBD and CBN are two of many chemicals found in cannabis plants. They differ from THC, the source of the marijuana “high.” CBD is present in marijuana but more abundant in hemp — cannabis plants that have little THC. CBN, meanwhile, is a THC derivative.
A 2017 study found that about seven out of 10 CBD products did not contain the amount of cannabidiol stated on the label. And about one in five contained THC.
What should you do if you use any of these products and have a drug test coming up?
CBD is promoted for easing anxiety, insomnia and chronic pain, among other ailments. The jury is still out on those uses, but there is some science behind the compound. Last year, the U.S. Food and Drug Administration (FDA) approved a drug containing pure CBD — called Epidiolex — for treating certain rare, severe seizures.
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.
It is difficult to say how much THC needs to be present to cause a positive drug test because this depends on several drug and patient-specific variables, and also the cutoff value for the test.
Theoretically, CBD should not show up on a drug test. However, because most CBD products are classified as a supplement, it is not regulated for safety and purity. This means that contamination of the CBD with THC (tetrahydrocannabinol) may and does occur, and this may show up on a drug test, depending on the cutoff level of the test and other factors listed below.
How much THC needs to be present to cause a positive drug test?
Confirmatory tests (Drug of Abuse Panel tests) use gas chromatography/mass spectrometry to identify specific molecular structures and to quantify the amount of drug or a substance present in the sample. These are more accurate than screening tests, but are also more costly and time-consuming and are usually reserved for situations that have significant legal, academic, forensic, or employment sequelae. These recognize cannabinoids rather than metabolites so should be able to distinguish CBD from THC.
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.
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.
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.