How to Read a Cannabis Lab Report (COA)

Montana requires marijuana and marijuana products to pass testing by a licensed testing laboratory before they can be sold in a dispensary. The Certificate of Analysis, or COA, is the lab report that shows what’s in it. Here’s what matters.

Cannabinoid profile

Look at Total THC, not just the raw THC number. Total THC accounts for the THCA that converts when heated. You’ll also see CBD and sometimes minor cannabinoids.

Terpene profile

Not every report includes it. Terpenes (myrcene, limonene, caryophyllene, pinene, and others) shape aroma and flavor and may influence how a product feels, though research on terpene effects in people is limited.

Safety testing

This section should read PASS for the required safety tests, such as pesticides, heavy metals, microbes (mold and yeast), and, for extracts and vapes, residual solvents. A failed result means the product shouldn’t reach the shelf. Passing tests show the sample met state limits; they aren’t a guarantee that a product is safe for everyone.

Montana’s labeling rules require each product’s label to carry a QR code that links to its certificate of analysis (ARM 42.39.314), so you can scan it before you buy. You can also ask us about the lab results for any product you’re considering.

Sources checked Nov 6, 2026: Montana DOR testing requirements; ARM 42.39.314 labeling rule. General information only; not legal or medical advice.

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