Not all cannabis testing is equal, but the USA’s National Institute of Standards and Technology (NIST) is aiming for it.
Legally speaking, the only thing distinguishing hemp from marijuana is its THC level. Not so long ago, the presence of any level of THC in cannabis made it marijuana at a federal level in the USA, but the 2018 Farm Bill made hemp with less than 0.3% THC legal.
THC testing can be a particularly difficult task where the cannabinoid is at low levels and one lab’s results may differ from another due to different methods or even just plain old human error. There can be a lot at stake – a farmer’s crop.
“If you’re going to confiscate a farmer’s crop, or subject a person to prosecution, you want to be sure that measurement is accurate,” said NIST research chemist Brent Wilson.
NIST has issued an invitation to labs to participate in a study that will assist them to produce the accurate measurements required to make a reliable call as to whether a cannabis sample is hemp or marijuana.
Labs that participate will be sent hemp and marijuana plant samples, and the labs will then measure the levels of various cannabinoids. The information will be sent to NIST along with detail on methodologies used. The labs’ results will be compared against NIST’s own testing of the samples. NIST will publish the labs’ measurement methods and results in the form of anonymized data so those interested can see the amount of variation.
NIST will evaluate the methods providing the most accurate results and then run the exercise again.
“We expect that in the second round, we will see less variability in the lab measurements, as labs overall improve their methods,” Mr. Phillips said.
As well as THC, the study will involve measurements of CBD (cannabidiol) and several other compounds.
On a related note, we reported last month the US National Institute of Justice had awarded a granted to NIST fund the development of simpler and cheaper THC testing.
Generally speaking, CBD and THC testing is increasingly under the spotlight in the USA due to the lack of standards and reports of “lab shopping” by some companies actively seeking out labs that will provide the results they want in terms of potency and contaminants. There are also reports of some cannabis companies gaming testing by adulterating samples.