Where's Weed

Cannabis Testing: Why It's Important for the Industry

Where's Weed

Published on Jun 7, 2020

Cannabis has certainly changed a lot over the last few decades including improved cultivation techniques, more efficient consumption methods, higher potency of THC - and now, product testing. In the past, both medical and recreational sides of the industry grew significantly without a lot of supervision, but now new rules and regulations are re-shaping the landscape. Currently, effective cannabis testing is forcing cultivators, processors, dispensaries, and distributors to tighten up processes to ensure safety for the end-consumer.

Why is Cannabis Testing Important?

Just as you don't want lead and other dangerous toxins in your water, food, air, clothing, or other everyday items, you don't want them in your cannabis products as well!

Prior to any sort of regulatory oversight in the cannabis industry in the early days, less than ethical growers and retailers would see selling cannabis products as an opportunity to make "a quick buck" without any quality control. Consumers with compromised immune systems have even gotten sick from consuming contaminated or inferior cannabis products.


Since cannabis products are consumed via a variety of methods for medical or recreational purposes, they must meet certain standards and regulations for acceptable limits without harming the consumers' health. Today, such standards and regulations are still under development in each state as the marijuana testing industry grows and matures. Note that there is no federal mandate for cannabis products since the federal government still considers cannabis to be illegal.

In addition to testing the products for safe consumption, they are also tested for potency. The higher the THC content is in a product, the more expensive the product will be.

Hence, there is an incentive for cultivators to maintain high quality products (and their buyers' trust). If they don't grow quality flower, then a significant amount of money could be lost, especially if contaminated products have to be thrown away or re-called.

Testing marijuana products is primarily conducted in professional cannabis testing labs for two main reasons: Determine the potency of the cannabis products and verify the safety of the products for consumption.

What to Test for in Cannabis?

In professional marijuana testing labs, they test for both potency and the presence of these contaminants in the cannabis products:



THC testing for potency is a necessity to allow for proper medical marijuana dosage or for consumers to control their "high" from a desired concentration of THC. The potency will express how much THC and CBD are in a product.


Microbes include bacteria, mold, fungi, and yeast. Keep in mind that microbes are common and abundant in our everyday lives. Only select harmful microbes will cause illness in humans. Cannabis plants and products can pick up microbes at any point from cultivation to handling and processing of the products.

Heavy Metals

Heavy metals are toxic at concentrations beyond acceptable levels in humans. Common heavy metals found in cannabis are lead, mercury, cadmium, and arsenic. The danger is ingesting them and accumulating in the body with repeated exposure to them over time. Our bodies are not able to remove them efficiently after exposure.

The cannabis plant is a "hyperaccumulator," which allows the plant to readily absorb metals from the soil, compared to other crop plants. The source of heavy metals could come from pesticides or naturally occurring in the soil.


Pesticides include fertilizers, insecticide, fungicides, miticides, and growth stimulators. They protect the plant from insects and microbes or to encourage faster growth. Unfortunately, since cannabis is illegal on the federal level, the Environmental Protection Agency (EPA) would not issue guidelines on the acceptable use of pesticides on cannabis.


Solvents are chemicals used in the process of extracting compounds from cannabis flowers. The resulting compounds include cannabinoids and terpenes. Harmful solvents, such as butane and propane, which are petroleum-derived solvents, are efficient at extracting compounds and cheap to use. When it comes to terpenes and testing, solvents could persist in end products if not refined and cleared out efficiently.

How to Test Marijuana: Types of Lab Tests

There are different methods to test marijuana in cannabis test labs. Here are lab test definitions for most commonly used methods:

Mass Spectrometry


Mass spectrometry is an analytical technique used to measure the mass of different molecules in the product. It will tell you the number of known materials, identify unknown compounds, and indicate the chemical properties of different molecules accurately. Within weed testing, it will be able to detect any impurities or contaminants in cannabis products, biological or not.


Chromatography is used to detect the concentration and if any particular compounds appear in the cannabis product. The technique will separate a cocktail of chemical compounds in a solvent into its individual components, so the components can be detected and analyzed.

Gas chromatography (GC) and high-performance liquid chromatography (HPLC) are most commonly used to detect residue solvents and concentrations of THC and CBD.

DNA Detection

The method of Polymerase Chain Reaction (PCR) is used to detect the presence of biological contaminants, such as fungi and bacteria. A small piece of DNA from the cannabis product is only needed because the PCR process will make millions of copies of that DNA for further analysis when the sample size is sufficient.

What's Next For Cannabis Testing?


Professional recreational and medical marijuana testing labs are incredibly important to maintaining the quality, integrity, and trust within the industry and for consumers. However, cannabis is still illegal at the federal level, so it's up to each state and testing labs to regulate the safety, quality, and potency of cannabis products, leading to a patchwork of different testing standards. What one state may consider toxic at a certain concentration may be acceptable to another state - a challenge that the cannabis lab testing industry is currently facing.

As of 2019, only 26 states required products to pass marijuana testing for medical and recreational markets. Some states are already starting to establish their first accredited cannabis labs. There have been discussions to establish nationwide testing where an independent third-party lab researcher will analyze cannabis samples, but it is not possible now because it is illegal to transport cannabis across state lines.

We anticipate as the cannabis industry matures and is legalized across all 50 states, the states and professional cannabis testing labs will implement better and uniform guidelines and standards across the United States.

Is cannabis testing important to you when buying products? Tell us why or why not in the comments below!


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