by Ryan Vandrey, PhD
The use of CBD and other hemp-derived products continues to grow as a result of legalization and increased awareness of potential health benefits. Related to this, use of these products has expanded to include a growing number of people, with many questions and concerns where research is needed to provide guidance. In this blog post, I will address the growing question if CBD will show up on a drug test.
Currently, drug testing is done for many reasons. For example, drug testing can be done to screen job applicants for illicit drug use prior to hire, to identify drug use during employment (especially in positions where there are safety concerns such as in the transportation industry), or in the context of forensic cases to determine whether acute intoxication from drug use may have been a factor in an accident or crime. In all of these cases, one of the common substances that is tested for is THCCOOH, which is a metabolite of THC, the primary psychoactive constituent of the cannabis (aka marijuana) plant. At high doses, THC can acutely impair performance and/or cause a variety of adverse effects such as anxiety, paranoia, or acute episodes of psychosis. Long-term daily use of THC can result in a pattern of problematic use similar to that observed with other drugs of abuse. Thus, this is an analyte of interest for most drug testing programs.
Because CBD and THC both come from the cannabis plant, and are structurally similar, there is concern that use of legal CBD or hemp products may be mistaken for THC and result in a positive drug test. This concern was raised a few years ago when a research study was published that showed CBD converted to THC when placed in the fluid found in pig stomachs. The reason for this is that CBD, when exposed to an acidic environment (low pH), can indeed convert to THC. However, subsequent studies, including one conducted in my lab, have shown repeatedly that an acute dose of CBD in humans will not convert to THC to the extent that would cause a positive drug test in either blood, saliva, or urine. However, that is not the end to this story… like most other things related to cannabis, there is nuance and complexity that have to be considered.
One complication stems from the fact that, although pure CBD did not convert to measurable amounts of THC when given in my laboratory, many “CBD” or hemp products do contain THC. The amount of THC allowed in a hemp product varies by jurisdiction, but usually the threshold allowed is 0.2% to 0.6% THC in the source cannabis for it to be categorized as hemp (a categorization solely defined by THC concentration). In one of our studies, several participants who vaporized a single dose of cannabis containing 0.39% THC (total dose was 3.7mg THC) tested positive in blood, saliva, and urine tests using common drug testing methods. Therefore, in hemp products, the higher the concentration of THC, the greater the likelihood of a positive drug test.
To put that in perspective of the current industry verbiage, there are three categories used to describe hemp/CBD products that is likely to relate to THC levels. “Isolate CBD” products are presumed to have only CBD and no THC or other chemical components of cannabis in them. “Broad Spectrum CBD” products are expected to contain trace amounts of THC and other chemicals, which are included based on the belief that small amounts of these substances work synergistically with CBD for a more robust effect. “Full Spectrum CBD” products are expected to contain the highest concentration of THC and other cannabinoids based on minimal processing of the raw plant material compared with isolate and broad spectrum products. Thus, the THC content in CBD products is expected to be: Isolate < Broad Spectrum < Full Spectrum.
Note however, that, as of now, there are no industry standards that relate any of these product categories to precisely measured levels of THC. Therefore, I recommend that you look for companies that provide a Certificate of Analysis for their products to see the actual amount of THC contained rather than relying on categories such as “Isolate”, “Broad Spectrum”, and “Full Spectrum”. The lower the amount of THC, the less likely you will have a positive drug test.