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The Growing Industry of Medicinal Cannabis Analysis
Most patients in the District of Columbia and the 16 states that have approved medical marijuana do not know the quality or potency of the cannabis (Cannabis spp., Cannabaceae) they receive to treat their health conditions. Due to the absence of generally accepted quality control and assurance in the industry, laboratories often present inaccurate and inconsistent results to the public. Amounts of the herb’s primary active ingredients like THC (tetrahydrocannabinol) and CBD (cannabidiol)—as well as levels of potential contaminants, such as pesticides and mycotoxins—are often unknown or imprecise. An increasing number of patients want consistency in their herbal medicinal products, however, and valid testing could bring the medicinal* cannabis industry greater legitimacy.

“The ability to ascertain potency and content of cannabis products sold in the dispensaries is critical if we are going to be able to allow patients to know what they are getting and for them to be able to re-access strains that are effective for them,” said Donald Abrams, MD, an integrative oncologist who studies clinical cannabis at the University of California San Francisco, where he is chief of hematology/oncology at San Francisco General Hospital (e-mail, February 15, 2012).

That the state-based medicinal cannabis industry is surviving without broadly implemented quality control standards speaks to both its infancy and lack of regulation at the state and federal levels as a result of its Schedule I controlled substance status. Since it was removed from the United States Pharmacopiea in 1942, the quality control and assurance that came to be imposed on other food products and botanical medicines have been neglected for cannabis.

This is on the cusp of changing, however, as several nonprofits, research organizations, and trade groups have initiatives specifically focused on creating a more scientific and legitimate medicinal cannabis industry. The British Columbia Institute of Technology, for example, joined with TerraSphere Systems in late 2010 to develop “quality standards for botanical drugs, in particular government licensed medicinal Cannabis sativa.1 Also in 2010, the US trade group American Herbal Products Association (AHPA) formed a Cannabis Committee with the goal of addressing hemp product commerce and agriculture, as well as “the emergence of medical cannabis as a legal product in numerous states.”2 “The AHPA Cannabis Committee intends to develop recommendations to regulators in states that allow use of medical cannabis,” said AHPA President Michael McGuffin. “It is possible that these recommendations to regulators will include suggestions on best laboratory practice. The committee’s work on this is just beginning so more specific details are not known at this time” (e-mail, April 10, 2012).

Additionally, the nonprofit American Herbal Pharmacopoeia (AHP) is currently developing a cannabis monograph under the direction of its Executive Director Roy Upton. As is typical of all AHP work, the cannabis monograph will provide industry with a variety of scientifically valid analytical methods used in the identification, purity, and quality assessment of cannabis and its crude products. 

“There is a critical need for quality controls to be put in place in the cannabis industry,” said Upton. “Those with commercial interests, including analytical labs, are jumping on the cannabis money bandwagon using unvalidated and/or inappropriate testing methodologies designed to give customers the answers they want to hear and promote a false sense of security. We see the same practices occurring in other sectors of the analytical labs industry and we hope the AHP monograph will help to correct some of this through greater transparency and methods validation” (e-mail, April 4, 2012).

The National Cannabis Industry Association (NCIA), a trade group in Washington, DC, has a current campaign aimed at helping to “develop and promote industry-wide standards and best practices.”3 And in February of 2012, 3 California labs—Steep Hill, Pure Analytics, and CW Analytical—founded the nonprofit Association of California Cannabis Laboratories (ACCL)4 to establish best practices for the industry.5 Both groups were created relatively recently and, aside from encouraging ethics and professionalism, have not yet taken concrete actions concerning validated standards and analytical methods.

In early 2011, an analysis of the testing practices of 10 anonymous cannabis labs found that “the precision and proficiency of a majority of cannabis testing labs compared favorably to other analytical testing industries,” but the authors noted that some labs “reported results that deviated substantially from the average, with unacceptable deviations of more than 25% from the mean.6,7 Three of the 10 labs performed unacceptably on half of the tests.”

“Seven out of the 10 labs we looked at came up with reasonably consistent potency results,” said Dale Gieringer, PhD, executive director of California NORML, a nonprofit that seeks to reform the state’s marijuana laws (e-mail, March 20, 2012). “The ones that didn’t had quality control problems; they either weren’t professionally run, or were using poor methodology.”6,7

Describing the state of most cannabis testing labs, William Clark, PhD—of the contract research organization Pure Naturals Certified, LLC—said, “Most labs lack the understanding of how to validate test methods. Without the proper testing and standardization, there will be no credibility with state and federal legislators. Today, many labs are in the business for the wrong reasons” (oral communication, April 10, 2012). 

Dr. Clark is a natural products chemist with 15 years of experience in the herbal and dietary supplements business, having been involved extensively in the development and validation of analytical test methods for Centrum Herbals as well as NSF International’s Dietary Supplement Certification Program. Pure Naturals Certified, based in Colorado, is in the beginning stages of establishing a lab that will isolate standards and validate testing methods for medicinal cannabis. Dr. Clark said he will soon meet and discuss this initiative with state legislators and the Colorado Department of Revenue, which enforces the state’s medicinal cannabis laws and policies.

“[Standardization] is the piece [Colorado is] looking for to legitimize themselves with the feds,” said Dr. Clark. “The reason the feds are focused on California is because their state regulations aren’t as well-defined as those in Colorado.”

Michelle Sexton, ND, a clinical cannabis researcher at Bastyr University in Redmond, Washington, who owns her own cannabis testing business, suggested that concerned consumers ask about the lab’s validation of methodology—such as, “Who did it and how was it done?”—as well as if the lab adheres to Good Laboratory Practices, has demonstrated complete separation of cannabinoids, which internal controls are in place to assure accuracy of results, and whether a “standard curve” is run with every sample set. If the owner or operator cannot provide the answers to these questions—or does not understand these questions—its analytical results may be questionable, she said (e-mail, April 3, 2012). (AHPA also provides a guidance document on its website to help consumers in choosing an analytical lab.8

Impact of Quality Cannabis Analysis

Why is it important that growers or dispensers invest in accurate analysis of their products? According to Dr. Sexton, it is a matter of public safety. “When much of the flowering top being sold is grown indoors, it is a target for fungal infection and pest infestation,” she said. “The potential profit and cost of growing indoors then necessitates using chemical warfare to bring a crop to market. If you consider that there are legitimately ill patients accessing this medicine—such as patients with cancer, HIV, neurodegeneration, liver disorders, kidney dysfunction, and more—it is an imperative to hold those who grow and dispense cannabis as medicine to a high standard of quality control.”

In addition, she continued, patients who have little tolerance or risk factors for some side-effects of THC may have distressing experiences from high-potency plant material, which a recent study reports is the trend rather than the exception.9

After obtaining an accurate analysis, a dispensary can label its products with potency content information, which Steve DeAngelo—executive director of Oakland’s Harborside Health Clinic dispensary—said enables patients to “more effectively self-titrate their cannabis intake,” and “identify a particular cannabinoid profile that works best for them, such as CBD-rich cannabis.” “Without cannabinoid potency testing,” he noted, “these patients would be unable to identify the CBD-rich medicine.”

When conducting clinical research on any substance, including cannabis, it is essential to know and document the potency of the study material. The only legal source of cannabis for research in the United States, the National Institutes of Drug Abuse (NIDA)—which contracts the University of Mississippi to grow its cannabis—labels the container that holds the cannabis cigarettes.10

“I have generally trusted the government and not had product re-tested,” said oncologist Dr. Abrams. “In fact, since you have to document the use of each cigarette in the research, sending one off to be confirmed might raise an eyebrow. NIDA cannabis is generally less than 7% THC with little or no CBD. For most of the studies I have done, we used their 3.5-3.9% THC cannabis.”

Some labs offer bacteria, mold, and contaminants testing, which Dr. Abrams said is helpful. “I always recommend that my cancer patients shop for organic produce to avoid herbicides, pesticides, and fertilizers—chemicals that we don’t really need to have in our bodies. I would assume the same should hold true for medicinal cannabis.” (AHPA published a guideline on microbiology and mycotoxins in botanical products in 2003.11)

Possibly raising into question the validity of all cannabis testing, a peer reviewer of this article noted that if the test is done on a cannabis bud different from the one the patient actually receives, the testing is “meaningless” because phytochemical content can range from plant-to-plant even if it is the same strain. Also, storage time can affect a cannabis sample’s potency. “This is why it is important to [ensure] that adequate sampling of an entire harvest is performed,” said Dr. Sexton. 

If state-based medicinal cannabis organizations were able to successfully implement high-quality testing standards and operations, might the US government have more respect for the industry and decrease raids and shutdowns?

“Not at all!” responded Dr. Abrams, a sentiment voiced by the majority of this story’s sources, including DeAngelo and Dr. Gieringer, who said, “it will take a top-down political decision by Congress and/or the President to change policy. This will happen only when there is enough public pressure for legalization.”

Dr. Clark, however, passionately and respectfully disagreed. Instead of being activists for legalization, he said, the industry should be focused on establishing scientific standards for testing potency and purity of medicinal cannabis. He noted that this will enable researchers to weed out redundant and ineffective strains currently in commerce, focus on strains and cannabinoid profiles that are effective for certain conditions, and implement a similar NSF-like program to certify dispensaries and growers.

“This is exactly what is needed to help the federal government feel comfortable to make a change for the better, for everyone,” he continued. “This opens the door for legislative change in Washington, DC.”

—Lindsay Stafford

* This article refers to cannabis used for medicinal purposes as “medicinal cannabis.” Some organizations, such as AHPA and Pure Naturals Certified, prefer to use “medical cannabis.” ABC acknowledges the various nomenclatures of this term.  


1. Converted Organics announces agreement between the British Columbia Institute of Technology and TerraSphere to design a research approach for quality standards for medicinal plant products [press release]. Boston, MA: TerraSphere Systems. November 11, 2010.

2. Cosgrove J. The cannabis conundrum: AHPA tests the controversial waters with the formation of a Cannabis Committee. Nutraceuticals World. May 20, 2010. Available at: Accessed April 4, 2012.

3. Campaigns. National Cannabis Industry Association website. Available at: Accessed April 12, 2012.

4. For immediate release. Association of California Cannabis Labs website. Available at: Accessed March 29, 2012.

5. The Association of California Cannabis Laboratories announces the establishment of a not-for-profit corporation [press release]. February 26, 2012. PRweb. Available at: Accessed March 28, 2012.

6. California NORML and Project CBD release the results of the first “Ring Test” to assess the accuracy of analytical laboratories [press release]. California NORML: San Francisco, CA. September 21, 2011. Available at: Accessed March 26, 2012.

7. Gieringer D, Hazekamp A. How accurate is potency testing? O’Shaughnessy’s, the Journal of Cannabis in Clinical Practice. Autumn 2011:17-18. Available at: Accessed March 26, 2012.

8. Dentali S. Choosing an analytical lab. Natural Products Industry Insider. September 15, 2003.  Developed in cooperation with the Analytical Laboratories Committee of the American Herbal Products Association (AHPA). Available at: Accessed April 4, 2012.

9. Slade D, Chandra S, Mehmedic Z, et al. Potency trends of ∆9-THC and other cannabinoids in confiscated cannabis preparations from 1993 to 2008. Journal of Forensic Sciences. 2010;55:1209–1217.

10. Stafford L. The state of clinical cannabis research in the United States. HerbalGram. 2010;85:64-68.

11. Guidance on microbiology & mycotoxins. American Herbal Products Association website. Adopted June 2003; last revised November 2009. Available at: Accessed April 4, 2012.