How cannabis is tested

In California, a licensed lab must test cannabis before it is sold. The lab measures THC and checks for things like pesticides, mold toxins and heavy metals. The results go on a lab report called a certificate of analysis. We start with California and will add other states.

By CHSA editorial team · Published 2026-10-04

Why testing matters

Lab testing gives you facts about a product that you cannot see, smell or taste: how strong it is, and whether it has more of certain contaminants than the state allows. In California, a licensed lab must test cannabis before it is sold.¹

These guides cover California’s rules. We have not yet written guides for other states, so do not assume the same rules apply there.

What labs look for

In California, every sample is tested for:²

cannabinoids, such as THC and CBD;
pesticides;
solvents and other processing chemicals;
heavy metals;
germs and mold toxins;
moisture;
foreign material.

Guides in this topic

What California tests cannabis for: each test, in plain language.
How to read a certificate of analysis: five steps to check a lab report.
Hemp, delta-8 and THCA in California: why hemp products are not tested the same way yet.