Why Lab Reports Matter
A Certificate of Analysis (COA) is the only way to verify what's actually in your cannabis. Labels can lie, but lab tests don't. Every legal cannabis product should have a COA available— if a brand can't provide one, that's a major red flag.
Anatomy of a Lab Report
Click each section to learn what it means and what to look for.
How to Verify a COA
Check the Batch Number
The batch/lot number on the COA should exactly match the product packaging. This confirms the test was done on your specific product, not a different batch.
Verify the Lab
Look up the testing lab. They should be state-licensed and ISO-certified. Most states have a list of approved testing facilities.
Check the Date
The test date should be recent and before the product's packaging date. Old tests or tests after packaging are red flags.
Scan the QR Code
Many COAs have QR codes linking to the lab's database. Scan it to verify the document hasn't been altered.
Compare to Label
THC/CBD percentages on the COA should closely match the product label. Small variations (±10%) are normal, large discrepancies are not.
Signs of a Quality COA
Red Flags to Watch For
Understanding Total THC
Raw cannabis contains THCa (non-psychoactive), which converts to Delta-9 THC when heated. The "Total THC" calculation accounts for this:
The 0.877 factor accounts for molecular weight lost during decarboxylation. This is why THCa is always higher than Total THC on flower COAs.
Pro Tips
Save COAs for Products You Love
Found a strain that hits perfectly? Save the COA. If you find it again, compare the terpene and cannabinoid profiles to the original—different batches can vary significantly.
Don't Chase THC Percentages
A 30% THC flower with poor terpenes often provides a worse experience than 18% THC with a rich terpene profile. Look at the whole picture.
Check Terpenes for Effect Prediction
High myrcene (above 0.5%) often means more sedating effects. Limonene and pinene suggest more uplifting, energetic experiences. Terpenes predict effects better than indica/sativa labels.
Be Extra Careful with Concentrates
Concentrates can accumulate contaminants. Always check residual solvent tests for extracts, and pesticide tests are especially important since they concentrate too.