Quality Control in the World of Cannabis: Page 2 of 2

October 24, 2019
Abstract / Synopsis: 

The cannabis industry is an emerging field with many unknowns. With unknowns comes uncertainty, and in a world where cannabis is attempting to break the negative stigmatism which it has been given, that uncertainty can be dangerous. Cannabis, whether for medicinal or recreational use, has testing requirements that it must meet, however, until recently most states have not required quality control to support independent laboratory testing results. Strict quality control requirements should have been mandated in all legal markets years ago, being that it is essential for validating testing results. Laboratories who are responsible for testing cannabis, no matter the matrix, should be required to run quality control to show that their results are reproducible, reliable, and defensible. This article covers the importance of quality control, how to implement it, and what cannabis cultivators, processors, retailers, and consumers should look for on laboratory reports and certificates of analysis.

All states that have legalized cannabis for medicinal or recreational purposes should implement rules which require quality control to be processed by any laboratory analyzing cannabis material or products. These rules should specifically outline what quality control is required but should also outline the acceptable ranges of recovery and relative percent differences that are allowed between samples. This alone will help decrease the variability in results among laboratories because all of the steps mentioned previously—including the development of a quality system, method validation, and implementation of standard operating procedures—will all precede the proper execution of batch quality control.

Each method used to quantify a set group of analytes (such as cannabinoids, terpenes, residual solvents, and so forth) have their limitations. These limitations can be unique to the analyte being tested because of their individual chemical structure and their varying interactions. In the environmental industry, the U.S. Environmental Protection Agency (EPA) outlines the recovery limitations for analytes within each method. For volatile organic compounds, EPA Method 8260B (5), the acceptable ranges vary between analytes. For example, in this method, acetone is considered a poor purging compound and therefore the recovery limits are not as stringent for it as they are for others. The same concept should be applied to the cannabis industry, however, there is currently not a sufficient amount of data available to determine what these recovery limits should be. To successfully determine what the values of recovery for analytes should be, studies need to be performed across many laboratories. Once this occurs, the data can be analyzed, and average percent recoveries and relative percent differences can be established.

Quality control is a major part of the batch processing and this data should be made readily available to clients. Full analytical reports should include the results of any quality control that was analyzed, along with the acceptable ranges of recovery, and relative percent differences between results. This will allow the client to have an additional sense of comfort in knowing that the results they have been given are reproducible, reliable, and defensible. Per ISO/IEC standards, any quality control results that fall outside of the acceptance criteria should be qualified as such and the client should be notified of the issue. These results can be included in a case narrative at the beginning of the report. By addressing the issues up front, the client is able to determine if they trust the results obtained by the laboratory or if they would like the sample to be reprocessed.

Transparency in the laboratory is crucial to legitimizing this industry. Laboratories need to be willing to communicate openly with their clients about issues that may arise and should not attempt to hide any results that are unfavorable. In the past, there have been several cases of laboratories falsifying data by either reporting out inflated potency results or inaccurately passing samples that contain dangerous contaminants. Requiring quality control with each laboratory batch, however, can help eliminate some of these issues. If laboratories are required to show evidence that they were able to spike a client sample with a known concentration of cannabinoids and recover the proper values, then there is supporting evidence to show that the laboratory is properly analyzing the sample for its true potency.

Most of the quality control that should be included with a full analytical report is difficult for the layman to comprehend and may require extensive explanation. For this reason, it is also important that analytical laboratories create user friendly certificates of analysis that allow all individuals to understand the results being portrayed. If a laboratory is performing quality control it is helpful to include a notation about this on the certificate of analysis for consumers, but there is no need to include this information. However, if anyone requests proof of quality control, the laboratory should be able to immediately produce the data.


Cannabis is currently undergoing a normalizing process. Regardless of its current status as a schedule 1 substance and decades of misinformation, public support and cultural acceptance continue to increase significantly. One of the main reasons for this positive shift is that claims such as cannabis being a more effective medicine, or a safer recreational drug, are now supported by a sufficient amount of scientific data. However, to further increase social acceptance and rebut negative stigmas, more data will be required, and the quality of that data will have a significant impact on what turn the industry takes next. Processes that confirm products are consistent with the specifications included on the package labels need to be implemented. Several cannabis producers are simply including the laboratory results without scrutinizing the data. It should be the responsibility of the laboratory and the cannabis producer, in conjunction, to ensure that the data is accurate before taking a product to market. To truly legitimize an industry that many have referred to as the “Wild West,” steps must be taken from the beginning to ensure that every product sold is in fact safe for consumption. This begins with the laboratory, as they are the entity responsible for ensuring that the analytical data is reliable, defensible, and reproducible, which can be accomplished through a strict quality control program.

  1. The NELAC Institute, 2016, Environmental Laboratory Sector, Volume 1: Management and Technical Requirements for Laboratories Performing Environmental Analysis.
  2. International Standard, 2017, ISO/IEC 17025: General Requirements for the Competence of Testing and Calibration Laboratories.
  3. Florida Department of Health, March 2018, Draft Rule 64-4.0xx - “Standards for Marijuana Testing Laboratories.”
  4. Florida Department of Health, March 2018, Draft Rule 64-4.016 - “Marijuana Testing Laboratories.”
  5. U.S. Environmental Protection Agency, 1996c, Method 8260B—Volatile organic compounds by gas chromatography/mass spectrometry (GC/MS).

Jini L. Curry is the Laboratory Director at Modern Canna in Lakeland, Florida. Christian Beauchemin is the Lead Analyst at Modern Canna. George Fernandez is the CEO of Modern Canna. Direct correspondence to: [email protected].

How to Cite This Article 

J.L. Curry, C. Beauchemin, and G. Fernandez, Cannabis Science and Technology 2(5), 52-55 (2019).