What a Michigan lab result can tell you, and where it stops

Licensed cannabis products in Michigan go through a testing lab before they reach a shelf. Labs report potency and screen for contaminants, and the results end up on a certificate of analysis, or COA, and in shorter form on the label.

Those numbers are useful. They're also easy to over-read. A THC percentage describes the sample the lab tested. It doesn't predict how strong a product will feel to you, and as our first article shows, a THC test in a driving case shows exposure, not impairment.

In this section we explain how to read a COA line by line, what total THC means, why results can differ between labs, and which questions to ask when a number looks too good. We stick to what was measured, who measured it and what the result can support.

Coming up: the most common mistakes people make reading lab results, and where to start if you've never opened a COA.