We've updated our Privacy Policy to make it clearer how we use your personal data.

We use cookies to provide you with a better experience, read our Cookie Policy

Analytical Cannabis Logo
Home > Articles > Testing > Content Piece

The USDA's Hemp Testing Rules Have Changed. Are You Ready?

By Martha Hernández

Published: Mar 21, 2022   
Listen with
Register for FREE to listen to this article
Thank you. Listen to this article using the player above.

Testing is a crucial aspect of the hemp industry; it stamps the legality of hemp in the US. But the testing rules have changed yet again. Is your lab ready to absorb the new requirements?

The United States Farm Bill, which is updated every few years, is the primary tool used by the federal government to set agricultural and food policies for the US. The 2014 Farm Bill, for instance, incorporated the 2014 Hemp Farming Act that made provisions to allow hemp cultivation for research purposes under state pilot programs. For the first time in decades, hemp could be cultivated on mass in the US.

After the 2014 Hemp Act was enacted, the United States Department of Agriculture (USDA) approved plans by state authorities and Indian Tribes to establish pilot programs for the domestic production of hemp. During the first year, only four states – Colorado, Kentucky, Vermont, and Indiana – had begun hemp cultivation under the pilots. Other states joined in subsequent years, and by 2018 only three states – Idaho, South Dakota, and Mississippi – did not have hemp programs.

During this period (2014-2018), hemp acreage in the US increased from zero to over 90,000 acres. By the close of 2018, Montana was producing the majority of hemp in the country, having a total of 22,000 acres for hemp cultivation. In 2019, after the 2018 Farm Bill had been passed, hemp acreage in the US shot up to 146,000 acres, exceeding the 143,000 acres record that had been set in 1943 before hemp cultivation became prohibited.

The state pilot programs came to an end in 2018 after the subsequent Hemp Farming Act was passed in 2018. The Hemp Farming Act of 2018 was a proposal to remove hemp from Schedule I of the controlled substances act (CSA). This move paved the way for the cultivation, use, production, and distribution of hemp and hemp products across the US.

“In the US, hemp is defined as cannabis that contains less than 0.3 percent THC by dry weight.”

Once the 2018 Hemp Act was passed, the USDA developed a national framework to regulate hemp production at the federal level. Consequently, an interim final rule (IFR) was published in October 2019 that gave guidelines on the production, sampling, licensing, and testing of hemp, besides disposal of hot hemp. The IFR took immediate effect and was later replaced by the final rule (FR), which was issued on January 15, 2021, and took effect on March 22, 2021.

All hemp testing laboratories must adhere to the new rules that have been outlined in the final rule. Moving away from the IFR, this new rule has brought about significant changes in how hemp is tested in laboratories. This includes the parts of hemp to be tested, the testing methods, and how “hot hemp” should be handled. Below is a breakdown of the changes in the hemp final rule that hemp testing laboratories need to be prepared for.


Figure 1: A schematic representation of the USDA’s new hemp testing rules (Figure courtesy of CloudLIMS).

Ten changes hemp testing labs must comply with

1.  Parts of the hemp plant to be tested

The FR has given licensed producers (LPs) and hemp testing laboratories some breathing room when it comes to “testable parts” of hemp. While the IFR restricted testable parts to the buds, the FR now allows samples to be taken anywhere from 5-8 inches from the main stem of the plant. This includes some leaves and flowers. Because these parts have fewer trichomes, it is expected that the incidence of “hot hemp” will be reduced. The sampling method selected should be good enough to collect representative samples and must be sufficient to assure that no more than 1 percent of the plants in the harvest lot exceed 0.3 percent THC (dry weight) at a confidence level of 95 percent.

2.  Post-decarboxylation or other similar methods to be used

Hemp testing laboratories are now required to use post-decarboxylation or similar reliable methods when testing for THC and should meet the AOAC International standard method performance requirements (SMPR 2019.003). Decarboxylation is a process that converts THCA (inactive) into THC (active) when hemp is exposed to heat. Approved test methods, therefore, must factor in the conversion of inactive THCA into THC. Methods that meet these criteria include gas and liquid chromatography.

3.  Negligence limit increased from 0.5 percent to 1 percent THC

Hemp that tests above 0.3 percent is illegal under federal law. However, the USDA gives some wiggle room for hemp that slightly exceeds this limit. The FR has increased this limit from 0.5 percent to 1 percent. In addition, LPs will not be given more than one negligent violation in a calendar year, irrespective of how many times hemp “turn hot” in each growing season. However, those who receive three or more negligent violations within a five-year period will be prohibited from cultivating hemp for the next five years.

4.  Compulsory drug enforcement administration (DEA) registration

All hemp testing laboratories must be registered with the DEA. However, laboratories have time until December 31, 2022, to meet this requirement. The registration enables laboratories to handle and test hemp under the Controlled Substances Act (CSA), 21 CFR part 1301.13.

5.  Measurement of uncertainty (MU)

As per the guide to the expression of uncertainty in measurement (GUM), the MU is defined as “a parameter, associated with the result of a measurement, which characterizes the dispersion of the values that could reasonably be attributed to the measurand.” Labs are required to calculate and report this value as they report the total THC concentration. For accurately determining MU, laboratories can refer to the guidelines specified by the International Organization for Standardization (ISO), Eurachem, or GUM.

6.  Reporting THC concentration

The FR maintained the maximum THC threshold at 0.3 percent THC by dry weight. Once a lab has tested each sample, it must report the total THC concentration to the LP, state department of agriculture, or tribal authority, and the USDA. Labs must fill out AMS Form 22 when submitting THC results to the USDA.

7.  Remediation of hot hemp

The final rule allows LP to remediate hot hemp. This means taking non-compliant hemp and making it compliant. First, the buds, trichomes, and flowers have to be removed. Subsequently, other parts (stalks, leaves, and seeds) of the hemp plant can be shredded to create homogenous biomass. The LP will need to submit a sample of the biomass to an authorized hemp testing facility, so that the hemp concentration can be retested to ascertain if it is now compliant.

8.  Disposal of hot hemp

The FR allows LPs to destroy hemp at their farms as long as they do not transport it elsewhere. LPs can plow under, compost, or burn the non-compliant hemp on-site. Hot hemp should be disposed of as per the guidelines defined by the CSA and DEA. A DEA-registered reverse distributor, or a federal, state, tribal, or local law enforcement officer authorized to handle cannabis should collect hot hemp for disposal.

9.  Internal lab SOPs

Laboratories that test for hemp are required to have an internal SOP that defines how hemp is tested and retested. The SOP should be available for viewing whenever it is requested by state agents.

10.  Use of validated test methods and quality assurance protocols    

Hemp testing labs must use validated test methods when testing for hemp. They must also have quality assurance protocols in place to guarantee the quality and reliability of the test results. Labs should also consider achieving ISO 17025 accreditation for quality assurance, as it is strongly recommended by the USDA.

Analytical Cannabis Expo North America Online 2022

Our industry-leading event is back for the fourth year in a row. Join us and our incredible panel of speakers for FREE for a discussion on the latest trends and innovations in cannabis science.

Find out more

Accelerate your lab’s compliance with a LIMS

A laboratory information management system (LIMS) is a vital key in ensuring that your laboratory achieves compliance with ease. A LIMS automates your entire system to make it both efficient and effective. A cloud-based LIMS solution helps ensure that all your processes are streamlined and targeted towards maximum output in real-time.

Benefits of a LIMS

  • Tracks hemp samples from the time they are presented to when they are destroyed.
  • Creates an alert when “hot hemp” samples are detected.
  • Shares test results automatically with the LP through the client portal and the USDA through integrated systems.
  • Provides access to sample information and test results in real-time.
  • Generates custom certificates of analysis (COAs).
  • Manages SOPs and stores documents.

Figure 2: A laboratory information management system (LIMS) to manage SOPs and documents with ease (Figure courtesy of CloudLIMS).


Hemp testing rules were changed by the hemp final rule (FR) that went into effect on March 22, 2021. Hemp-testing labs need to be registered with the DEA by the end of 2022, and they must also be compliant with the other changes to avoid being penalized for non-compliance. Digitization, powered by a LIMS, provides a unique opportunity for hemp testing laboratories to achieve 100 percent compliance with ease.

Martha Hernández

Scientist, CloudLIMS.com

Martha is a chemist with expertise in diverse areas of analytical chemistry. She has worked as an analyst at a licensed third party analytical laboratory, where she focused on developing and validating analytical methods for bioequivalence studies. Later, she had served as a quality control expert in the analytical domain and as a monitor in clinical trials. Her interest in the clinical industry led her to be a part of two of the biggest hospitals in Mexico where she gained expertise in hematology, microbiology, and blood banking. Later, she became a member of the team of forensic chemical experts and started working from day one as a specialist in narcotics and drugs. This enabled her to gain rich experience in GC-MS, FTIR, HPLC-MS/MS, ICP-MS, and other analytical techniques for the separation, detection, and quantification of different molecules such as cannabinoids. She had participated in multiple oral trials defending her legal opinions and worked as an expert consultant. She had worked on the synthesis of small molecules for testing them on multi-drug resistant bacteria and mycobacteria, further developing her analytical skills in column chromatography, thin-layer chromatography, microbiology, and compound elucidation by NMR and HRMS. She carried out a research stay at the University of Barcelona with the organic synthesis team. She had also worked on natural products in France and presented her work at conferences in the USA and France. She received awards and accolades for her exceptional work. She has participated in several conferences as a moderator as well. Martha holds a Bachelor’s in Clinical Chemistry from the Faculty of Medicine UANL and a Master’s in Pharmacy from the Faculty of Chemical Sciences UANL, Mexico.


Like what you just read? You can find similar content on the topic tags shown below.

Cultivation Policy Science & Health Testing

Stay connected with the latest news in cannabis extraction, science and testing

Get the latest news with the FREE weekly Analytical Cannabis newsletter