Is It Hemp or Cannabis? NIST Develops Revolutionary Testing To Distinguish Between The Two

The National Institute of Standards and Technology, or NIST, is launching a study that will help both forensic labs and industry labs accurately measure the amount of THC, CBD, and other compounds in cannabis plant material. These measurements are key to distinguishing between hemp and marijuana and are important for accurate labeling and product safety. 


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AUTHOR: Heather Allman



NIST Study Will Help Labs Distinguish Between Hemp and Marijuana



The National Institute of Standards and Technology, or NIST, is launching a study that will help both forensic labs and industry labs accurately measure the amount of THC, CBD, and other compounds in cannabis plant material. These measurements are key to distinguishing between hemp and marijuana and are important for accurate labeling and product safety. 


From a legal perspective, a small number makes a big difference.


This story is important because inaccurate measurements can lead to crops and products being improperly seized and can have a chilling effect on commerce, to say nothing of peoples’ liberties. And it is interesting in that NIST — a federal research agency — is leading a study that is designed to help the cannabis industry as well as law enforcement. 



NIST Responses from Brent Wilson and Melissa Phillips


Cannabis Law Report:  Why the scientific interest in cannabis and hemp? 


NIST: The legalization of hemp in 2018 put extra importance on making accurate quantitative measurements for THC, THCA, and Total THC. Forensic laboratories and Cannabis (hemp and marijuana) testing laboratories are now required to distinguish between hemp and marijuana based on the concentration of total potential THC in the Cannabis samples (below or above 0.3 %). These measurements could have significant legal and economic impacts. Additionally, consumers need to have confidence that the values included on product labels are accurate similar to food products they might purchase at the grocery store.


CLR: What are the key conclusions of the NIST study? 


NIST: CannaQAP is a Quality Assurance Program that will provide continuous interlaboratory studies to the forensics and cannabis testing communities with two exercises a year. The first exercise involving hemp oils was conducted last year (more info here), and we will make the results publicly available in the next couple of months. This report will include a summary of the measurement variation between labs and provide insights into biases and challenges observed during the study. The second exercise announced last week involves hemp- and marijuana-type plant samples, and we expect to publish the results from that study later this year.


Beyond the published results, the goal of these studies is to help labs improve their measurement methods, and we expect that measurement consistency between labs will improve as we conduct additional rounds of studies.


CLR:  Can you share the most interesting or challenging story that has happened to you since you began the study? 


NIST: The second exercise of CannaQAP is currently open for participants to sign up. The first exercise focused on the measurements of cannabinoids in two hemp oils, while the second exercise focuses on the measurements of cannabinoids, moisture, and toxic elements in hemp (THC < 0.3 %) and marijuana (THC > 0.3 %) samples. The shipping of the hemp samples was straightforward with no legal considerations as NIST assured all samples were below 0.3 % THC.

However, the inclusion of marijuana samples in exercise #2 brought its own set of challenges in terms of following the proper protocols and paperwork to provide these samples domestically and internationally.

These samples fill an important gap by providing QC materials that laboratories can have the utmost confidence in.


CLR: Main reason for this study? What positive impact does this study have? 


NIST: CannaQAP was developed to help Forensic and Cannabis testing laboratories demonstrate and improve measurement comparability and/or competence. A QAP is akin to a proficiency testing scheme but without the pass/fail grade. All results from QAP studies are peer-reviewed and made publicly available as published NIST Internal Reports (IRs).

The results will be anonymized so that readers will be able to see the amount of variation between labs but not how any specific lab performed (labs will know their own performance of course).  

In addition to helping labs demonstrate and improve their measurement capabilities, this study will also help NIST design and characterize Cannabis reference materials.

NIST is currently working on developing a hemp plant reference material targeted for release early 2022. In the meantime, while NIST RMs are not available, CannaQAP samples can provide participants with Quality Control materials to be routinely used in

in their laboratory.


CLR:  How do authenticity and trust factor into your current course(s) of action? 


NIST: NIST has been running similar programs ( for three decades. These programs focus on accurately measuring other botanicals, foods, health markers in blood tests, environmental contaminants, and others. 


NIST has a long track record of success in this area because, aside from our measurement capabilities, we are non-regulatory and industry participants trust us to provide a neutral platform that allows all participants an equal opportunity to improve their measurement performance.



CLR:  What is the biggest challenge the study faced? How did you solve it or work to change it? 


NIST: The first exercise of CannaQAP focused on the cannabinoid measurements in hemp oil because oils are naturally more homogeneous than Cannabis plant materials. With plant material, the concentrations of THC or CBD can vary greatly across a single plant, let alone to an entire field of plants.

So for us the challenge was to prepare samples for the CannaQAP studies (~5 kg) and reference material (~50 kg) while ensuring the THC or CBD values are consistent across the entire sample. The second challenge we encountered corresponds to the shipment of Marijuana samples as previously summarized.


CLR: Any unexpected or ancillary discoveries that enlightened you concerning the study? 


NIST: Each cannabis material, whether it be a plant-based or from an oil source, presents an unique challenge in preparing adequately homogenous evaluation materials to be used in the CannaQAP. 


CLR: What future mark do you strive to make in the growing national Cannabis/Hemp space that you feel is the very most important, and why? 


NIST: The measurements laboratories make have significant legal and economic impacts on consumers, farmers, and product developers. By helping labs make more accurate measurements, we hope to provide authorities with the tools they need to enforce the law fairly, allow consumers to enjoy their legal products safely, and support the growth of commerce in this important sector.


CLR:  What still needs improvement? What ideas or actions need to come to fruition, in regards to NIST Study? 


NIST: CannaQAP is initially focused on the measurement of cannabinoids in hemp oils and Cannabis plants because the legal and economic impacts discussed previously. This program is still in the early stages, but we expect it to continue for many years.

NIST is still learning about the areas that need improvements such as product safety. NIST plans to expand beyond the initial focus on cannabinoids to include potential harmful contaminants, including toxic elements, pesticides, mycotoxins, microbiological contaminants, etc.

These are all areas that the Cannabis community needs a platform to help improve analytical measurements.


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