Here’s What Makes Potency Testing of Cannabis Edibles Difficult

“But there’s no such thing as a standard sample prep,” Hennesy says. “Those are considered, essentially, trade secrets for every different lab. Every lab will have a different test prep.” So it falls to producers to work with labs to develop “robust, internal validation programs, [meaning] the lab uses several different processes to check and double-check [that] the results they’re providing you are accurate.”

Every lab can create its own validation processes, and Hennesy warns against labs that do little validation. “Everyone’s equipment is different, and everyone’s test prep is different,” he says. “A lab really should do validation on their test prep and do validation on the individual equipment they’re using. Most importantly, they should have a different validation procedure for every type of product.”

Dr. Wise agrees, calling this process “matrix-specific testing, meaning crackers are treated differently than meat is treated differently than fruit.”

To test cannabinoids, labs must extract the molecules from the food products in which they appear, but Dr. Wise says the ingredients of any given product may affect the extraction process. “It’s important that the lab you’re working with either has tested your kind of food product previously or you’re able to work with them and send them an uninfused sample and then an infused sample,” she notes. “They can run background tests to ensure that they’re getting all of the cannabinoids out of your specific product.” (She adds that producers should avoid any lab using the outdated and unscientific division of cannabis products into “Indica” and “Sativa.”)

Hennesy stresses that, if a lab doesn’t have a validation process for the specific product in question, it should work with the producer on developing validations for the exact product the producer needs tested. This is particularly important, Dr. Wise says, for beverage producers working with water-solubilized cannabinoids, such as those in nanoemulsions. Producers must be clear with their labs when they are using such cannabinoids in order to get accurate results—but the more labs know about how the product is made, the better.

“You should also be providing information to them,” Hennesy says. “The more the lab knows about what they’re actually testing and what barriers you might have created within the product-development process that could hinder testing, the easier it is for them to tailor their procedures to give more accurate results.”

Pushing the Upper Limits

In many cases, producers testing for potency are simply looking to determine the cannabinoid content of their food or beverage products so they can list it on their packaging. Yet, in some states, producers are testing against edibles potency limits. In the states of Washington and Colorado, for example, THC is capped at 10 mg per edible or beverage serving, with a maximum of 100 mg THC per package. (Under far more stringent Canadian law, THC is capped at 10 mg per package.)

In theory, the chief challenge producers should face when testing against upper limits on THC is making sure their products don’t exceed the THC limits; however, Washington-state cannabis business-intelligence expert Jim MacRae, PhD, who has published a series of reports showing “friendly labs” allowing companies to “pay for potency” in multiple states, warns that some labs are willing to fraudulently undercount cannabinoids, allowing products onto the market with more than 10 mg of THC per serving.

However, Dr. MacRae notes that, unlike falsely inflated cannabinoid content, products that are labeled 10 mg per serving but that deliver a much stronger dose are actually more desirable to many experienced consumers. He adds that increasing the THC dose in infused products—and particularly in high-end infused products with expensive ingredients, such as Belgian chocolates—might cost producers very little. “A very small fraction of the cost of the thing is the cannabinoids,” says Dr. MacRae. “If you can double that, that’s doubling the cost of only a small proportion of your product cost.” If consumers discover a product is “a stronger 10 mg per serving,” that might increase its appeal among those looking to consume more THC.