Cannabis Product Testing: Pass or Fail?


In any industry, third-party or independent lab testing provides validation for the manufacturer’s safety and label claims on any product intended for consumption. The cannabis industry is no different. Cannabis products can be divided into two main categories: inhalable and non-inhalable cannabis products. Before these products can be sold to the medical cannabis patient or adult use consumer, they must be tested in a third-party lab which includes several different quality assurance controls. 

Why test cannabis?

In the U.S., most of the legal cannabis market states require licensed cultivators, manufacturers, and distributors to present passing Certificates of Analysis (COAs) for their inhalable and non-inhalable products to reach the consumer but the extent of the testing requirements vary. Examples of inhalable products include flower, pre-rolls, infused pre-rolls, and concentrates used for vaping. Tinctures, edibles (infused beverages, gummies, chocolates, etc.), topicals, balms, and bath soaps are examples of non-inhalable products. COAs dictate whether the product is safe for consumption as well as the composition of the particular chemovar. The COAs can include results for cannabinoids, pesticides, terpenes, heavy metals, residual solvents, microbial impurities, water activity, and moisture depending on state-specific standards and regulations. States can also choose to be less rigorous in their testing and only include results for some of these analytes. Cannabis can have a huge variety of analytes in any given chemovar, so measuring what is present and how much of it is there is important whether it is the specific cannabinoids (such as THC and CBD), heavy metals (such as lead and arsenic), microbial impurities (such as Salmonella), pesticides, and more. Many states set acceptable limits for these analytes based on what they consider safe for consumption. Labs can provide a numerical measurement, also known as quantification value, as well as a corresponding “pass” or “fail” designation for the sample being tested.

In the regulated cannabis market, METRC is a technology solution used in many states to track and trace all forms of cannabis from seed to sale, including the quality control and quality assurance that happens in the labs. The methods used by the testing lab must adhere to the standards and regulations put in place by state-specific cannabis regulatory bodies, which vary from state to state. This disconnect between states without federal oversight has made it easier for rogue labs to create false results when creating their COAs. For example, some labs have developed their methods to ensure inflated cannabinoid results when making their COAs, which in turn causes products to be sold at a higher price to the consumer, due to the nature of concentrated or higher testing products having a greater market value to consumers. Alternatively, growers can also submit “spiked” samples to the lab to boost their results. For this reason, some states require the lab technician to go to the grow site and select their own samples for analysis.

Based on the reference lab’s results and findings, labs producing false COAs could be held accountable by issuing a public warning about the infraction and then shutting the testing lab down.

Unfortunately, there aren’t many checks in place to ensure that the results displayed on the COA are not inflated with higher than actual THC/THCa values, or other falsehoods. A reference lab, a state-managed lab that checks the accuracy and efficacy of third-party labs, that only works for the safety of the cannabis patient and consumer, should double-check the testing results, methods, and science practices of all state testing labs. Then, based on the reference lab’s results and findings, labs producing false COAs could be held accountable by issuing a public warning about the infraction and then shutting the testing lab down.

Some states are taking this type of corruption more seriously. In Michigan, if any sample tests over 28% for THC level, the regulatory agency will audit those results. California’s Department of Cannabis Control has been inspecting and reviewing results, which has led to suspensions and one attempt to revoke a license which was ultimately overruled by a judge. Some blame the consumers for forcing the market to seek higher and higher THC percentages, but that is not always the case. In July 2022, a small group of consumers in Arkansas filed a lawsuit against a group of four companies for selling products with overinflated THC numbers.

It is important to have every product tested for safety, efficacy, and consistency particularly because these factors will contribute to the success of the business. If a product does not pass testing it must be destroyed or, depending on the issue, the product can be remediated by a licensed manufacturer. For example, if a flower fails microbial testing it can be remediated into a concentrate. However, remediation does not guarantee a pass. A remediated concentrate may not fail microbial testing, but instead fails pesticides or heavy metals due to all the components of the flower being condensed into a concentrate. The remediated concentrate could also fail for residual solvents if the concentrate was not made safely. The remediated product must pass testing before being released to the consumer for retail sale, and even then, the COA does not state a product went through remediation. In California’s cannabis industry, if a sample fails any test the batch that it represents cannot be delivered to dispensaries for retail sale. Instead, it can be remediated or reprocessed and fully re-tested again. If a batch fails a second re-testing after the remediation process, or if a failed batch is not remediated, then the entire batch must be destroyed

Depending on the U.S. state’s requirements, analytical tests will be performed on all cannabis products before it reaches the consumer.

Qualifications for third-party labs

According to a national review delivered by Americans for Safe Access, the regulations of each state determine who can do testing. For example, when comparing the cannabis regulations of Maryland, Colorado, California, Oregon, New York, and Florida, each state upholds the importance of using third-party testing or independent testing labs (ITLs). These states require registered testing labs to oversee the quality of the cannabis products within their respective legal markets and alert the state-led regulatory body when a product fails testing.

It’s a straightforward process to become a testing lab. There’s a non-refundable registration fee required, which can range anywhere from $100 – $1000. In most states, once a lab is registered with the respective regulatory body, it must obtain ISO/IEC 17025 accreditation, which indicates that they are a reliable source to perform competent lab testing and produce reliable results. Registered testing labs must pass proficiency testing to prove their methods are valid to use for testing on cannabis products. Those same labs are required to use methods that are certified through agencies such as AOAC, FDA, EPA, NTI  (Oregon), or other methods approved by the state’s regulatory body. Some states have standardized methods put in place, which is an important safeguard that prevents licensed manufacturers, cultivators, and distributors from shopping around in their state’s cannabis market for a lab that will give passing results. Labs can set their own Limit of Detection (LOD) and Limit of Quantification (LOQ) values, which can skew results to appear as though they are passing when they are not. Rogue labs will intentionally design their analytical methods not to detect analytes at all or not give an accurate concentration of the analytes present.

“Because a lab can set its own LOD and LOQ, it can legally pass a sample for pesticides, heavy metals, or residual solvents that another lab might fail.”

In theory, if all labs tested the same way, the results should be consistent and would take the same amount of time to produce no matter the lab performing the tests. There would not be an issue of inflated THC/THCa values, false passing results, fast two-day turnaround times, and other malicious acts that have the potential to put consumers at risk. False passing results, better known as falsifying data, can look like running a sample several times and then choosing the elevated THC level to report or running a sample several times because the sample is failing for an analyte and then choosing to report the passing result because it finally happened after the 8th time running the sample. Falsifying data can also look like deleting peaks that are actually present during the data analysis process of testing, thus causing a sample to wrongfully pass. This process of picking and choosing which data to report is known as cherry-picking data and is disreputable in the science community.   

As more U.S. states come online with medical and adult-use cannabis programs, lab testing regulations have the opportunity to evolve and improve. By implementing third-party testing lab compliance and regulatory enforcement, combined with education for medical cannabis patients and consumers, the states are setting the foundation for sound federal regulation when cannabis is re- or de-scheduled.

 Alina Butler, M.Sc.  is an experienced molecular biologist, cannabis scientist, edible production lead, and science communicator striving to make the world a better place using science.

Author: Alina Butler, M.Sc.


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