LII:Past, Present, and Future of Cannabis Laboratory Testing and Regulation in the United States/Laboratory testing of cannabis
With a sense of history and a better understanding of the regulations and standards affecting cannabis testing and use, this chapter can finally dig into the specifics of the current and future state of laboratory testing of cannabis and related products in the U.S. Here we look at the analytical aspects of cannabis, methods and guidelines used as well as the equipment and software typical to cannabis testing labs.
3. Laboratory testing of cannabis
Analyzing the chemical constituents of the Cannabis plant is a difficult task due to its matrix, and the task becomes even more difficult when it's added to food and other matrix types, requiring established and consistent methods for testing. As mentioned in the prior chapter, regulators, users, and the testing industry are calling for improved standardization of both the production and testing of medical and recreational marijuana. Without proper testing, several issues are bound to arise:
- label claims may not match actual contents;
- contaminants may linger, causing illness or even death;
- chemical properties and medicinal benefits of specific strains and their unique cannabinoid-terpene profiles can't be isolated; and
- research on potential therapeutic qualities can't be replicated, hindering scientific progress.
In 2011—a year before any U.S. state had enacted broad legalization of recreational marijuana—California NORML reported that its assessment of analytical cannabis testing laboratories' accuracy found that while California labs broadly reached +/- 20 percent consistency from a replicate sample, three out of 10 provided unfavorable results on at least half of their tests. Similar wide-ranging discrepancies were also found among edibles, extracts, and tinctures, and NORML found that none of the labs could reach two decimal points precision of cannabinoid results, despite laboratory claims stating otherwise. Another report out of the state of Washington in January 2015, not long after recreational marijuana sales to the public (requiring accredited lab testing prior) began, found blind tests of recreational marijuana at dispensaries could range as much as 7.5 percent in accuracy from their corresponding label. Further issues in 2016 with alleged partiality by some Washington testing laboratories prompted emergency proficiency testing rules to be enacted. ("Proficiency testing" essentially requires a laboratory in question to test a sample with known properties, and then those results are compared to those of a neutral third-party lab testing the same sample.) Additional testing problems in Alaska and Washington labs in late 2017 found high disparities between two different testing labs, as well as a laboratory that couldn't "properly perform a coliform test that looks for bacteria." More recent testing abuses by labs in Nevada and Arizona muddy the waters even further.
These discrepancies and deficiencies highlight the growing need for homogenization of testing methods and procedures, if not nationally at least across an entire state. Such homogenization would, in theory, not only positively affect the quality of product but also provide greater consumer confidence that label and product match. As Marketing Director Scott Kuzdzal of Shimadzu pointed out during a January 2017 webinar on analytic testing of cannabis, poor sample preparation, lack of thorough testing, and the manual process itself—which can introduce user error, particularly when good laboratory practices aren’t used—all can contribute to discrepancies between label and product. When dispensaries, edible manufacturers, and supplement companies perform insufficient lab testing or overstate claims on labels, it reduces consumer confidence, and both state and federal authorities—including the U.S. Food and Drug Administration (FDA)—have to interject.
As was mentioned prior, efforts to improve testing methods and procedures—with the goal of seeing the best of them become standards—are ongoing. Where are those efforts now, and where are they going? Before we can examine that, we first need to briefly look at what aspects of cannabis are actually being analyzed.
3.1 Analytical aspects of cannabis
Somewhere between 104 and upwards of more than 140 of the over 750 constituents of Cannabis sativa have been identified as cannabinoids, active chemical compounds that act in a similar way to compounds our body naturally produces, and new cannabinoids continue to be identified during cannabis research. Many of our body's cells have cannabinoid receptors capable of modulating neurotransmitter release in the brain and other areas. The plant's cannabinoids vary, with each bonding to specific receptors in our body, providing differing effects. From a theoretical and medical standpoint, crafting a strain of cannabis that has specific cannabinoids that can aid with a particular malady, while also carefully reproducing the grow conditions to consistently make that strain in the future, is a desirable but difficult goal to achieve. However, even as new strains are developed, identifying an existing strain effectively has its own set of challenges, as Mudge et al. point out: "the total [tetrahydrocannabinol] and [cannabidiol] content is not sufficient to distinguish strains [though] a combination of targeted and untargeted chemometric approaches can be used to predict cannabinoid composition and to better understand the impact of informal breeding program and selection on the phytochemical diversity of cannabis."
Lab testing of cannabinoids is done primarily as a measure of psychoactive "potency," though cannabinoids have many other potential therapeutic uses. Current laboratory testing looks at only a handful of cannabinoids; more research and development of analytical techniques that can quickly and accurately detect and separate the rest is required. Some of the major cannabinoids tested for include:
- THC (∆9-Tetrahydrocannabinol): This is the most commonly known cannabinoid found in cannabis, notable for its strong psychoactive effects and ability to aid with pain, sleep, and appetite issues. Included is its analogue ∆8-Tetrahydrocannabinol (which shows notably less strong psychoactive effects than ∆9) and its homologue THCV (Tetrahydrocannabivarin), which tends to appear in trace amounts and has a more pronounced psychoactive effect, but for a shorter duration. THCV shows promise in fighting anxiety, tremors from neurological disorders, appetite issues, and special cases of bone loss. Also notable is ∆9-THCA (∆9-Tetrahydrocannabinolic acid), a non-psychoactive biosynthetic precursor to THC.
- CBC (Cannabichromene): This non-psychoactive cannabinoid is found in trace amounts; however, it tends to be markedly more effective at treating anxiety and stress than CBD (see next). It's also notable for its anti-inflammatory properties and potential use for bone deficiencies.
- CBD (Cannabidiol): CBD is a non-psychoactive component of cannabis, typically accounting for up to 35 to 40 percent of cannabis extracts. It acts as a counter-balance to THC, regulating its psychoactivity. It's been researched as a treatment for anxiety, sleep loss, inflammation, stress, pain, and epilepsy, among other afflictions. Included is its homologue CBDV (Cannabidivarin), which is also non-psychoactive and demonstrates promise as a treatment for epileptic seizures. Also notable is CBDA (cannabidiolic acid), a non-psychoactive biosynthetic precursor to CBD.
- CBG (Cannabigerol): This cannabinoid is also non-psychoactive but only appears in trace amounts of cannabis. It has potential as a sleep aid, anti-bacterial, and cell growth stimulant. Also notable is CBGA (cannabigerolic acid), a non-psychoactive biosynthetic precursor to CBG.
- CBN (Cannabinol): CBN is mildly psychoactive at best and appears only in trace amounts in Cannabis sativa and Cannabis indica. It occurs largely as a metabolite of THC and tends to have one of the strongest sedative effects among cannabinoids. It shows promise as a treatment for insomnia, glaucoma, and certain types of pain.
Mandated lab testing of terpenes—volatile organic compounds that distinctly affect cannabis aroma and taste—is done primarily as a way to ensure proper labeling of cannabis and related products, including extracts and concentrates, so buyers have confidence in what they are purchasing. However, additional lab research goes into terpenes as they also show potentially useful pharmacological properties, and they demonstrate synergies (referred to at times as the "entourage effect") with cannabinoids, requiring further research. Testing for specific terpenes (discussed later) has histoically been less of a standardized practice, though it's rapidly improving. Commonly tested terpenes by third-party testing labs include:
Generally speaking, a contaminant is an unwanted substance that may show up in the final product, be it recreational marijuana or a pharmaceutical company's therapeutic tincture. The following are examples of contaminants that laboratories may test for in cannabis products.
Pesticides: Pesticides represent an oft-discussed aspect not only of growing cannabis but also performing analytical testing on it. One of the core issues, again, is the fact that on the federal level marijuana is illegal. Because it's illegal, government agencies such as the Environmental Protection Agency (EPA) have historically failed to develop standards or guidelines for what's safe when it comes to residual pesticides in cannabis, let alone how to best test for them. Additionally, researchers have faced their fair share of difficulties obtaining product to test over the years. The end result is we're only now barely understanding how inhalation of pesticide-coated marijuana smoke affects long-term health, and standard methods for pesticide application and testing have been slow to develop. With numerous pesticide products and little oversight on what growers apply to their plants, combined with the technical difficulty of testing for pesticides in the lab, pesticides remain one of the most difficult contaminants to test for. That said, several classes of of pesticides are commonly applied during cannabis cultivation and can be tested for by labs:
- avermectins: function as an insecticide that is useful against mites, which are a common problem for cultivators
- carbamates: function as an insecticide, similar to organophosphates, but with decreased dermal toxicity and higher degradation
- heterocyclics: function as a broad set of compounds with many industrial uses, including as pesticides
- organochlorides: function as a broadly useful chemical in applications such as plastics, cleaning agents, insulators, and pesticides
- organophosphates: function as the base of many insecticides and herbicides, valued for its easy organic bonding
- pyrethroids: function as the base of most household insecticides and exhibits insect repellent properties
Solvents: In 2003, Canadian Rick Simpson published a recipe of sorts for preparing cannabis extract via the use of solvents such as naphtha or petroleum ether. Claiming the resulting oil helped cure his skin cancer, others hoping for a cure tried it, and the solvent method of preparation grew in popularity. Dubious healing claims aside, the solvent extraction method remains viable today, though it has evolved over the years to include less harmful solvents such as supercritical carbon dioxide, which has low toxicity, low environmental impact, and beneficial extraction properties. However, chemical solvents are still used, and if not evaporated out properly, the remaining solvents can be particularly harmful to sick patients using the extract. As for what solvents should be tested for, it gets a bit trickier, though Chapter 467 of United States Pharmacopeia and The National Formulary, the Oregon Health Authority's December 2015 technical report on contaminant testing of cannabis, and the Massachusetts Department of Public Health's response to public comments on cannabis testing provide helpful guidance. Listed solvents include benzene, butane, cumene, dimethoxyethane, ethanol, hexane, pentane and propane, among others.
Heavy metals: 2013 research on contaminant testing on the behalf of Washington State provides insights into heavy metals and why they're looked for in cannabis testing. That research, as well as other more recent sources, tell us:
- Heavy metals contribute to several health problems, including those of a neurological nature.
- Cannabis can "hyperaccumulate metals from contaminated soils."
- Research parallels can be found in tobacco research and how the FDA regulates heavy metal content in foods.
- The most prominently tested heavy metals include arsenic (As), cadmium (Cd), chromium (Cr), copper (Cu), lead (Pb), mercury (Hg), and nickel (Ni).
Mycotoxins and microorganisms: "The ideal conditions for cannabis growth are also ideal for the growth of potentially harmful bacteria and fungi, including yeast and molds," say Shimadzu's Scott Kuzdzal and William Lipps, "therefore microbial contamination poses health risks to consumers and immunocompromised individuals." In truth, these concerns have already borne out. In fact, the University of California, Davis reported in February 2017 one of its patients had contracted an incurable fungal infection from inhaling aerosolized marijuana. They later tested 20 marijuana samples from Northern California dispensaries—using specialized techniques—and found a wide variety of potentially hazardous microorganisms.
The degree to which such contaminants commonly appear in grown and stored cannabis material and to which microbiological contaminants should be tested is not clear, however. As mentioned previously, the U.S. EPA has historically had little in the way of significant guidance on cannabis testing, including microbiological contaminants. Like heavy metal testing, parallels are drawn from microbial testing guidelines and standards relating to tobacco and food, where they exist. As warm, moist environments are conducive to microorganism growth, maintaining stable moisture levels during cultivation and storage is essential. Regularly measuring water activity—how moist something is—is particularly useful as a front-line preventative tool to better ensure microbial growth is limited. Regardless, testing of some kind is still required by many U.S. states, including for organisms such as:
- E. coli
3.2 Methods and guidelines
Now that we've addressed what's being tested for, we can move on to how they're being tested and what's being done to improve testing methods and procedures, including associated guidelines and recommendations. This section will focus on current and promising techniques using generalizations based on information from multiple sources. If any guidelines and recommendations are known, they'll be included.
Random, representative sampling is encouraged. When dealing with solid cannabis, BOTEC Analysis recommends a "quartering" method that divides the sample into four equal parts and takes portions from opposite sections of a square-shaped arrangement of the sample. For liquid cannabis products, remembering to stir before sample collection is advised. Sampling techniques may also vary depending on the constituent being tested, as with terpene testing, which may favor full evaporative technique (FET) headspace-based (HS) sampling for reducing certain sampling biases. Another consideration may be the matrix being tested, as when deriving a sample from a cannabis-laden edible; the QuEChERS approach used by food safety labs for pesticide testing may have practical use. In fact, a variety of parallels have been drawn from the food and herbal medicine industries' sampling guidelines, including from the Codex Alimentarius Commission's CAC/GL 50-2004 General Guidelines on Sampling as well as various chapters of the United States Pharmacopeia and The National Formulary. As the Association of Public Health Laboratories (APHL) points out, "[g]ood sampling is key to improving analytical data equivalency among organizations," and it provides a solid base for any future testing and standardization efforts.
Additional sampling insight can be found by examining other states' guidelines, e.g., Massachusetts' Protocol for Sampling and Analysis of Finished Medical Marijuana Products and Marijuana-Infused Products for Massachusetts Registered Medical Marijuana Dispensaries, as well as ASTM D8334/D8334M-20 Standard Practice for Sampling of Cannabis/Hemp Post-Harvest Batches for Laboratory Analyses.
3.2.2 Cannabinoid testing
Quantifying cannabinoids for label accuracy is a major goal of testing, though calculation and testing processes may vary slightly from state to state. Despite any differences, laboratorians generally agree that when testing for cannabinoids such as THC and CBD, as well as their respective biosynthetic precursors THCA and CBDA, the methodology used must be scrutinized. The naturally occurring THCA of cannabis isn't psychoactive; it requires decarboxylation (a chemical reaction induced by drying/heating that releases carbon dioxide) to convert itself into the psychoactive cannabinoid THC. Chemical calculations show that the process of decarboxylation results in approximately 87.7 percent of the THCA's mass converting to THC, with the other 12.3 percent bubbling off as CO2 gas. The problem with this in the testing domain is gas chromatography (GC) involves heating the sample solution. If you, the lab technician, require precise numbers of both THCA and THC, then GC analysis poses the risk of under-reporting THC total values. As such, liquid chromatography-diode array detection (LC-DAD) may be required if a concise profile of all cannabinoids must be made, primarily because it provides environmental stability for them all during analysis. If GC is used, the analysis requires extra considerations such as sample derivatization.
The APHL briefly describes analysis methods of cannabinoids using both LC and GC on pages 31–32 of their May 2016 Guidance for State Medical Cannabis Testing Programs. They also point to New York Department of Health - Wadsworth Center's various guidance documents (MML-300, -301, and -303) for methodologies when testing sample types other than solids, particularly using high-performance liquid chromatography photodiode array detection (HPLC-PAD). Also worth noting is that ASTM's Subcommittee D37.03 has been working on various standard methods for determining cannabinoid concentrations using different chromatography techniques, while the Association of Official Agricultural Chemists (AOAC) has already developed a Standard Method Performance Requirement (SMPR) for analyzing cannabinoids in hemp (i.e., low THC cannabis varieties).
- Fourier-transform infrared spectroscopy (FTIR; has limitations, such as requiring standard samples tested w/ other methods)
- Gas chromatography-flame ionization detection (GC-FID; requires sample derivatization for both acid and neutral compounds; good with standards like 5α-cholestane, docosane, and tetracosane)
- Gas chromatography–mass spectrometry (GC-MS; requires sample derivatization for both acid and neutral compounds; good with standards like deuterated cannabinoids)
- Gas chromatography–vacuum ultraviolet spectroscopy (GC-VUV)
- High-performance liquid chromatography photodiode array detection (HPLC-PAD; stable for all forms of cannabinoids)
- High-performance liquid chromatography UV detection (HPLC-UV)
- Liquid chromatography–mass spectrometry (LC-MS; can reduce or eliminate selectivity challenges and speed up testing, though at an increased price cost and need for greater laboratory expertise)
- Supercritical fluid chromatography (SFC; newer technology w/ added benefits)
- Thin-layer chromatography (TLC; older, less common technology)
- Ultra-performance chromatography (UPC; newer technology w/ added benefits)
Also worthy of note is recent investigation of viably using nuclear magnetic resonance (NMR) spectroscopy as a more affordable and rapid solution to identifying cannabinoid contents and profiles of samples. Conferences, research, and articles over the last four or five years have advanced the use of NMR spectroscopy for cannabinoid analysis.
3.2.3 Terpene testing
Identifying and quantifying terpenes is one of the more difficult tasks facing laboratorians, according to Cassidy:
Terpenes present an analytical challenge because they are nonpolar and structurally similar, and many structural isomers exist. Mass spectrometry (MS) cannot distinguish terpenes that co-elute from a GC column because many have the same molecular weight and share fragment ions.
Goldman et al. share Cassidy's view about MS, though reminding that it has some benefits over flame ionization detection (FID). They note that recent MS methods add another level of confirmation for terpene identification using retention indexing and electron impact mass spectral matching.
Of course, types of gas chromatography work; but like cannabinoids, terpenes can degrade with the high heat of gas chromatography. Combined with the problems mentioned above, highly specialized gas chromatography processes that include additional steps, such as full evaporation technique headspace gas chromatography flame ionization detection (FET-HS-GC-FID), can be used to produce cleaner results, particularly for volatile components. It's less clear if high-performance liquid chromatography (HPLC) is used frequently; some entities such as Eurofins Experchem Laboratories claim HPLC works best for them, while others such as Restek Corporation claim the method is problematic at best.
- Full evaporation technique–headspace–gas chromatography–flame ionization detection (FET-HS-GC-FID; tends to be semi-quantitative)
- Gas chromatography–flame ionization detection (GC-FID)
- Gas chromatography–mass spectrometry (GC-MS)
- Gas chromatography–tandem-mass spectrometry (GC-MS/MS)
- Gas chromatography–vacuum ultraviolet spectroscopy (GC-VUV)
- Headspace–gas chromatography–mass spectrometry (HS-GC-MS)
- Headspace–solid-phase microextraction (HS-SPME)
- High-performance liquid chromatography (HPLC; may have limitations due to coelution of terpenes and cannabinoids at certain ranges)
3.2.4 Contaminant testing
Pesticides: Gas and liquid chromatography methods are by and large the staple of testing methods for pesticides, which remain "the hardest analyses that are going to be done in the cannabis industry." Goldman et al. echo the sentiment: "pesticide testing is difficult and requires advanced analytical instrumentation and highly skilled staff to meet regulatory demands with a robust, accurate, and precise test method." Notably, high-performance liquid chromatography–tandem-mass spectrometry (HPLC-MS/MS) tends to be one of the most thorough methods says Emerald Scientific's CTO Amanda Rigdon. "Ninety-five percent of the pesticides out there can be analyzed by HPLC-MS/MS, although there are some that you would need a GC-MS/MS for," she says. A popular sample extraction method for detecting multiple pesticide residues in cannabis is the QuEChERS (quick, easy, cheap, effective, rugged, and safe) method, which shows "acceptable recoveries and relative standard deviations" for almost all known pesticides, though the release of heat and increase in pH of QuECHERS may degrade particularly sensitive pesticides in the sample. QuECHERS may also not be ideal for some labs due to its organic solvents having a tendency of extracting hydrophobic compounds like cannabinoids. However, other methods such as solvent extraction (such as with acetonitrile) with dispersive solid-phase extraction (dSPE) cleanup and energized dispersive guided extraction (EDGE) may also been used. Common testing methods that have historically been used, after sample preparation, include:
- Gas chromatography–electron capture detection (GC-ECD)
- Gas chromatography–mass spectrometry (GC-MS)
- Gas chromatography–tandem-mass spectrometry (GC-MS/MS)
- Liquid chromatography–mass spectrometry (LC-MS; also high-performance or HPLC-MS)
- Liquid chromatography–tandem-mass spectrometry (LC-MS/MS; also high-performance or HPLC-MS/MS)
Solvents: Testing for solvents is largely standardized into a few options, which have parallels to existing pharmaceutical testing standards outlined in Chapter 467 of United States Pharmacopeia and The National Formulary (USP <467>):
- Headspace–gas chromatography/mass spectrometry (HS-GC/MS)
- Headspace–gas chromatography/tandem-mass spectrometry (HS-GC-MS/MS; may be required when high concentrations of terpenes are present)
- Headspace–gas chromatography–flame ionization detection–mass spectrometry (HS-GC-FID-MS)
- Full evaporation technique–headspace–gas chromatography–flame ionization detection (FET-HS-GC-FID)
Massachusetts and Oregon—and likely other states—have used a variety of guidance documents such as USP <467>, reports from the Commission of the European Communities' Scientific Committee on Food (now the European Food Safety Authority), and the International Conference on Harmonization's (ICH) Q3C(R5) to set their action level testing values for particular solvents. The AOAC provides another standardized option in the form of their SMPR 2019.002.
Heavy metals: The methods used for quantifying levels of highly toxic metals in plants depend on ease-of-use, level of accuracy, and overall cost. Sample preparation typically includes the use of closed-vessel microwave digestion to get the sample into solution for analysis. Once prepared, the following methods are most common for testing cannabis and other plants for heavy metals:
- Atomic absorption spectrometry (AAS; may struggle to meet detection limits)
- Inductively coupled plasma–atomic emission spectroscopy (ICP-AES), sometimes called inductively coupled plasma optical emission spectrometry (ICP-OES) (at times coupled with an ultrasonic nebulizer)
- Inductively coupled plasma–mass spectrometry (ICP-MS; a preferred technique)
- Inductively coupled plasma–tandem-mass spectroscopy (ICP-MS/MS)
Mycotoxins and microorganisms: A standard method of testing for the existence of microorganisms is through the process of culturing a sample in a Petri dish, a common diagnostic method in microbiology. Enzyme-linked immunosorbent assay (ELISA) is also used, particularly to identify mycotoxins. However, Petri culture analysis isn't rigorous, and ELISA can at times be time-consuming, as it's limited to one mycotoxin per test. The following are other, more precise techniques that are improving laboratorians' analyses, particularly using DNA snippets of microbiological contaminants:
- Quantitative polymerase chain reaction (qPCR)
- Whole metagenome shotgun (WMGS) sequencing
- Matrix-assisted laser desorption/ionization (MALDI)
- High-performance liquid chromatography (HPLC)
- High-performance liquid chromatography–fluorescence spectroscopy (HPLC–FS)
- Liquid chromatography–tandem-mass spectrometry (LC-MS/MS)
- Liquid chromatography–electrospray ionization–tandem-mass spectrometry (LC-ESI-MS/MS)
- Liquid chromatography–atmospheric pressure chemical ionization–tandem-mass spectrometry (LC-APCI-MS/MS)
The extent of mycotoxin testing required remains in question by several entities. The APHL claims "[t]here is no readily available evidence to support the contention that cannabis harbors significant levels of mycotoxins." The Oregon Health Authority takes a more middle-ground approach, noting that testing for E. coli and Salmonella will "protect public health," though Aspergillus only deserves a warning for people with suppressed immune systems due to its prevalence in the environment. USP <561> recommendations largely limit mycotoxin testing of botanical products to those borne from root or rhizome material, "which THC-containing cannabis products presumably do not possess," emphasizes the APHL.
Regardless, U.S. Pharmacopeia's Chapter 561 remains a useful document for testing guidelines and limits regarding microbials, as does the AOAC's SMPR 2019.001 for the detection of Aspergillus. In the less common case of dealing with powdered cannabis—a relatively new THC extract form—Chapter 2023 provides at least some testing parallels, though Dr. Tony Cundell, a microbiologist consulting for the pharmaceutical industry, suggests USP <2023> doesn't go far enough for immunocompromised patients.
Somewhat related and worth mentioning is moisture content testing. As previously mentioned, warm, moist environments are conducive to microorganism growth, and regularly measuring water activity is useful for the prevention of microbial growth. The APHL references specifications from the Dutch Office of Medical Cannabis that recommend water content be between five to ten percent in cannabis.
3.3 Laboratory accreditation
Chapter two briefly discussed the accreditation of a cannabis testing laboratory, but a bit more should be said. As was mentioned prior, cannabis labs and their relevant tests are typically accredited to the ISO/IEC 17025 standard. This includes the likes of the ANSI National Accreditation Board (ANAB) and the American Association of Laboratory Accreditation (A2LA). However, through the American Council of Independent Laboratories (ACIL) and its Cannabis Working Group (CWG), a specific national standard for cannabis lab accreditation is beginning to take shape. Referred to as CanNaLap (Cannabis National Laboratory Accreditation Program) and based on ISO/IEC 17025, the national standard has been developed "as a mechanism to ensure the effective performance of all cannabis testing labs operating in the United States." Additionally, the ACIL also seeks for the FDA and U.S. Department of Agriculture (USDA) to "support and endorse" CanNaLap "as a means to establish standards of competency for testing market participants." ANAB has already begun to address CanNaLap as part of its supplemental accreditation requirements, though time will tell if CanNaLap becomes a fully adopted national accreditation standard in the U.S.
There's little in the way of standardization for lab reporting of cannabis test results, though some U.S. states have outlined requirements for what must be included in such reports. The Oregon Health Authority's Oregon Administrative Rules, Chapter 333, Division 64, Section 0100: Cannabis Sampling Procedures and Testing stipulates that any report must include total THC and total CBD (by dry weight) and, if discovered, "all tentatively identified compounds (TICS) that meet the identification criteria." It also lays out requirements for pesticides, failed tests, limits of quantification, and specimen identifiers such as test batch number. California dictates reported values for cannabinoids and contaminates be shown on the COA with three significant figures and water-activity level at two significant digits, as well as "pass" and "fail" statuses, demographics, sample history, test methods used, and more.
Pennsylvania provides another example with its medical marijuana program (28 Pa. Code Chapter 1171), which includes a section on test results and reporting (1171.31). The regulations stipulate reporting by electronic tracking system, with stipulations on using certificates of analysis which include lot/batch number and the specific compounds and contaminants tested. Regulations aside, it's largely up to the laboratory—and often by extension, the software they're using—to decide how a report is formatted. Some labs like Seattle-based Analytical 360 offer clean, color-based certificates of analysis, with high-magnification photographs, the chromatogram, potency, cannabinoid content, contaminant content, and explanation of limits, with the name of the approving analyst. Others may simply generate a computer printout with the basic data and a legend. Reports may originate from the measuring device itself (e.g., an integrator in a chromatography device), a middleware or data station attached to the instrument, or a laboratory information management system (LIMS) that accepted data from the instrument.
Though not directly related to laboratory testing, it's worth noting states also have their own reporting requirements for growers, processors, and dispensaries. Both Oregon and Washington, for example, require monthly reports related to medical marijuana transfers.
3.5 Lab equipment
As indicated in previous sections, spectrometry and chromatography have played and will continue to play an important role in cannabis laboratory testing. This should not be surprising: "mass spectrometry is superior to other spectral techniques in such features as sensitivity, selectivity, generation possibility of molecular mass/formula, and combinability with chromatography." Analyzing complex chemical compounds that have many features and which are at times difficult to differentiate from each other proves challenging, but these technologies excel in meeting that task. Refer to the previous "Methods and guidelines" section to note the specific technology associated with each molecule and contaminant. Aside from spectrometry and chromatography equipment, the analysis of microorganisms in cannabis may turn to DNA analysis methods that require additional equipment such as a thermal cycler (qPCR) or sequencer (WMGS), or ELISA, which utilizes a photometer or spectrophotometer. Of course, preparing and storing samples requires equipment as well, such as microplates, centrifuges, comparison standards, capillaries, chemicals, columns, Petri dishes, scales, and disposable gloves. Software-based data management systems may also constitute equipment and are discussed in the next section.
When it comes to purchasing lab equipment specifically for cannabis testing, a 2015 interview with Emerald Scientific's CTO Amanda Rigdon (then with Restek Corporation) provides good advice:
- Industry-specific instrumentation isn't needed in most cases as most of the techniques and equipment used in food and herbal medicine testing have strong parallels to cannabis testing.
- That said, some sample preparation tools, standards, and consumables specifically marketed to the industry may very well make the job quicker and more reliable.
- Appropriate sample preparation techniques are just as vital as the equipment you use.
- Do your research; many instrument companies are examining methodologies usable on conventional equipment, lessening the need for more expensive devices.
- If buying used equipment, make sure the original manufacturer is still in business and producing consumables and replacement parts. Make sure your planned methods match the equipment, and make sure it's not so old that it can't be serviced by a qualified technician.
For more on specific laboratory equipment and vendors, see the next chapter in this guide.
Laboratories increasingly depend on software to analyze, store, and share critical data from instruments and experiments. This has led to the development of laboratory-specific software like the laboratory information management system (LIMS), electronic laboratory notebook (ELN), and chromatography data system (CDS; sometimes CDMS). These and other software systems such as "seed-to-sale" programs can also play an important role in the cannabis testing laboratory.
Laboratories of all types use LIMS software to manage the wide variety of data, testing and analysis workflows, and other enterprise activities typical of them. This generally includes—but is not limited to—sample reception, workflow management, sample tracking and analysis, quality control, instrument data management, data storage, reporting, and document management. The cannabis testing laboratory is no exception, though its activities differ slightly from, for example, a clinical pathology laboratory. As such, a few additional features outside of what's typically found in a generic LIMS are required.
- sample loading screens optimized for the industry, including differentiation between medical and recreational marijuana
- pre-loaded compliant test protocols, labels, and reports optimized and readily adjustable for a rapidly changing industry
- tools for creating new, compliant test protocols, labels, and reports
- a web API to integrate with state-required compliance reporting systems
- chain-of-custody (CoC) tracking, when necessary
- support for inventory reconciliation
As previously discussed, industry-specific test protocols largely focus on cannabinoids, terpenes, and a wide variety of contaminates, including excess water. However, as regulations continue to be in a state of flux and not particularly standardized, most LIMS developers are including the ability for users to adjust their protocols and even add new ones. And while CoC functionality is not entirely foreign to generic LIMS, it's particularly important in an industry where currently transporting even a cannabis test sample across state lines can create huge problems.
In cases where daily sample processing is infrequent and only a couple of chromatography machines are used, laboratories may weigh a decision between a LIMS and a chromatography-specific CDS, although the ability to produce an acceptable certificate of authenticity (CoA) and document the CoC are still factors, along with any state reporting requirements.
Cannabis LIMS solutions
The following LIMS solutions in Table 1 are known to specifically offer features that support the cannabis testing laboratory:
Scientists on the research side of cannabis are certainly using CDSs from Agilent, Thermo Scientific, Waters, and other to manage the data coming out of their chromatography equipment, and slowly but surely some of those CDSs are beginning to also support spectrometer data management in a similar way. Additionally, some chromatography system developers will collaborate with CDS vendors to develop software drivers—code that essentially acts as a translator between a device and a program—so chromatography devices can interact fully with the CDS.
The CDS likely has a place in the cannabis testing lab as well, though it may depend on the lab's data management needs and goals. In more complex labs with multiple instruments and significant daily processing workflows, a LIMS may make more practical sense.
Some vendors like Thermo Fisher Scientific—discussed in the next chapter—offer a CDS in conjunction with its other chromatography systems marketed for the cannabis testing industry. Other common CDS options include:
The use of seed-to-sale software is a growing trend that is only tangentially related to laboratory testing of cannabis. Rather than at testing laboratories, seed-to-sale software is found at cultivation sites, production facilities, and dispensaries, and that software is typically designed to be able to integrate with testing laboratory or other software. The goal: create a complete record of transaction, from the grown plant to the lab, producer, and seller. This sort of tracking is mandated in various ways by many U.S. states with legalization laws. "It’s there to prevent the diversion of marijuana, which the federal government still lists as a Schedule I substance, the most dangerous class of drugs," wrote Daniel Rothberg of the Las Vegas Sun in December 2015. "Tracking also ensures product safety, assists with audits, and helps facilitate recalls." This type of software is able to track plant yields, attempted theft or diversion, patient preferences, extraction methods, batch weights, and various financial statistics for analysis.
Seed-to-sale software vendors
The following vendors are a representative sample of those that offer a seed-to-sale system for the cannabis industry:
- Ample Organics, Inc. - Ample Organics
- Bio-Tech Medical Software, Inc. - BioTrackTHC
- Chetu, Inc. - Custom software solutions
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Citation information for this chapter
Chapter: 3. Laboratory testing of cannabis
Title: Past, Present, and Future of Cannabis Laboratory Testing and Regulation in the United States
Edition: Fourth edition
Author for citation: Shawn E. Douglas
License for content: Creative Commons Attribution-ShareAlike 4.0 International
Publication date: August 2022