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October 18, 2019

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Marijuana goes through rigorous checks in the Silver State

DigiPath Labs Tour

Steve Marcus

Johnny Chan, an analytical chemist, checks cannabinoid levels in a sample at DigiPath Labs, a cannabis testing facility, Wednesday, June 6, 2018.

Before marijuana is ready for sale in Nevada dispensaries, it must first go through a laboratory screening process for a variety of pesticides and contaminants, as well as tests to determine potency levels.

Investigations and advisories

There are instances when the Nevada Department of Taxation issues health advisory warnings for products that fail microbial testing. To review the most recent advisories, visit

Recreational marijuana isn’t legal at the federal level, meaning there are no federal standards or regulations for approving cannabis products for sale. That leaves policymaking up to each state. Nevada—which fancies itself a leader in the booming, new industry—has “very stringent policies” that affect every aspect of the testing process, ensuring cannabis products outsourced from cultivators are safe to consume, local cannabis attorney Amanda Connor said.

There are 11 independent labs licensed through the state, said Eden Larson, a spokeswoman for the Department of Taxation.

“When Nevada developed the laboratory regulations, they looked at other states and adopted some of the best practices from around the country,” she said.


Nevada law requires that testing facilities hire a scientific director with a doctorate in chemical or biological sciences.

All labs must follow standards published by the American Herbal Pharmacopoeia as well as recommendations from the American Herbal Products Association, the law states. Those standards ensure cannabis samples are as free from foreign matter as “practically possible,” as well as having consistent coloring with no signs of gray or black, both indicators of fungal infection.

Larson said lab inspections are scheduled regularly throughout the year, and each lab must go through an accreditation process, pursuant to the International Organization for Standardization, by an impartial entity.

And labs must be independent from all other parties involved in the cannabis industry. The law states: “No person with a direct or indirect interest in the laboratory has a direct or indirect financial interest in: A medical marijuana dispensary, a facility for the production of edible marijuana products or marijuana-infused.”

Testing process

Labs collect raw samples of flower, edibles and concentrates from cultivators to test for contaminants, pesticides, fungi, toxic metals and moisture.

The department has an acceptable test-level on each sample, Connor said. If a sample fails any of these tests, the cultivator must destroy the entire batch of that product.

Potency levels are also measured so consumers will know what effects the product will have on them.

Cannabis chemistry contains more than 400 chemical entities, with 80 unique to the plant itself, according to the National Institutes of Health. Delta-9-tetrahydrocannabinol, or THC, is the most active component.

The most common way to test for potency is through a process called High Performance Liquid Chromatography, or HPLC, which separates and quantifies the chemical compound. Through this process a sample is combined with solvent, such as ethanol, and placed into a high-pressure tube containing a material that attracts certain molecules.

Cannabinoids including THC and CBD will move at different speeds through the tube, which then attracts certain molecules. The varying speeds allow lab technicians to label the samples. Cannabinoid value labeling seen on packaging comes from these measurements.

Labs will also test for terpene levels, which are aromatic oils that give cannabis products their distinctive tastes and smells, such as berry, lavender or mint. Terpenes also interact with other compounds in the cannabis plant, which can in part manipulate the effects of varying strains.

This story originally appeared in the Las Vegas Weekly.