How to Read a COA (Certificate of Analysis)
A certificate of analysis — a COA — is a lab report for a specific batch of product. It's issued by a testing laboratory, not by the brand, and it's the closest thing this industry has to ground truth. Most people never open one. The ones who do usually stop at the THC number.
Here's how to actually read it.
First: match the batch
A COA describes one batch, not a product line. Somewhere near the top you'll find a sample ID or batch/lot number. That number should match the batch printed on the package in your hand. If a store shows you a certificate that can't be matched to your specific batch — or reuses one certificate across everything they sell — the document tells you nothing about your jar.
Every product we sell carries its batch number on the product page and in our live lab directory, so you can make that match yourself.
The cannabinoid panel
This is the potency table. For THCA flower, three lines matter most:
- THCA — the acid form of THC, reported as a percentage by dry weight. This is the number most hemp flower is sold on.
- Delta-9 THC — for hemp, this must be at or below 0.3% on a dry-weight basis under the 2018 Farm Bill. It's the line that separates hemp from marijuana in federal law.
- Total THC — many labs calculate this as delta-9 THC + (THCA × 0.877). The 0.877 factor accounts for the weight lost when THCA converts. If a label quotes one big number, check which of these it actually is.
Two abbreviations you'll see in the table: ND means "not detected," and <LOQ means the compound was present below the lab's limit of quantitation — too little to measure reliably. Neither is a defect; they're the lab being precise.
The contaminant panels
Potency gets the attention, but the safety panels are why full-panel testing matters:
- Pesticides — screened against a list of banned or limited compounds.
- Heavy metals — typically lead, arsenic, cadmium, and mercury. Cannabis is a bioaccumulator: it pulls metals from soil, which is why clean cultivation practices matter.
- Microbials — yeast, mold, and specific pathogens like salmonella and aspergillus.
- Mycotoxins — compounds produced by certain molds.
- Residual solvents — relevant for concentrates made with solvent-based extraction.
- Moisture / water activity — an indicator of how well flower was dried and cured, and how resistant it is to mold in storage.
Each panel gets a pass/fail against the testing standard used. A COA that only shows a potency table is a potency test, not a full panel — useful, but incomplete.
Checking the certificate itself
A few habits from years of reviewing these documents professionally:
- Look up the lab. The certificate should name an independent, accredited laboratory (ISO/IEC 17025 accreditation is the common standard) — with a real address and license or accreditation number.
- Check the dates. A COA from several years ago describes a batch that's long gone.
- Be skeptical of astronomical numbers. Genetics put practical ceilings on cannabinoid content. Numbers well above what the plant reliably produces deserve a second look, not a celebration.
- Verify at the source when you can. Many labs host their certificates for direct verification, and QR codes on certificates should resolve to the lab's own domain — not a brand's marketing page.
How this works at THCa Hub
Every batch we list is numbered and tracked in our lab directory. A batch is marked verified only when its full-panel certificate is on file — until then it shows testing in progress, plainly. We'd rather show you an honest "pending" than a borrowed badge.