Reading a Certificate of Analysis: What Buyers Actually Need to Check

A Certificate of Analysis is the single most-referenced document in cannabis and hemp sourcing, and also one of the most commonly skimmed rather than actually read. It's easy to check for the presence of a CoA and move on. It's more useful to know what on that document actually tells you something, and what's just formatting.

Start with who issued it

The single highest-value check on any CoA is whether it came from an independent, accredited third-party lab — not an in-house lab run by the supplier or grower themselves. An in-house CoA isn't automatically fraudulent, but it removes the independence that makes third-party testing meaningful in the first place. Look for the lab's name, accreditation body, and ideally a way to verify the lab is real and currently accredited — not just a logo on a PDF.

Batch-specific, not reference

This is the check that catches the most problems in practice. A CoA should correspond to the specific batch or lot number you're actually receiving — not a "representative" or reference CoA from an earlier harvest or production run that the supplier reuses across multiple orders. Ask directly: does the batch number on this CoA match the batch number on my shipment? If a supplier can't answer that clearly, the CoA isn't telling you anything about what you're actually buying.

Know which THC metric you're looking at

For hemp and cannabis products specifically, check whether the CoA reports Delta-9 THC specifically or total THC (which factors in THCA using a conversion calculation). These aren't interchangeable, and a product that reads as compliant under one measurement can read differently under the other. If your destination market uses a total-THC standard and your CoA only reports Delta-9, you don't actually have documentation of compliance for that market — you have documentation of a different, easier-to-pass standard.

Contaminant screening, not just potency

Cannabinoid potency numbers get the most attention because they're the headline figures, but a thorough CoA should also cover contaminant screening — pesticide residue, heavy metals, microbial contamination (mold, bacteria), and residual solvents for extracted products. A CoA that only reports cannabinoid content and skips contaminant screening entirely is incomplete for most commercial purposes, particularly for anything destined for ingestible or pharmaceutical-adjacent use.

A practical checklist

• Independent, accredited lab — not in-house.
• Batch number matches your actual shipment, not a reference sample.
• Delta-9 THC or total THC clearly specified, matched to your destination market's standard.
• Contaminant screening included — pesticides, heavy metals, microbials, residual solvents where relevant.
• Testing date recent enough to be meaningful — cannabinoid content can degrade over time, so a CoA from a year-old test on a fresh batch is worth questioning.

None of this is about distrust by default — most established suppliers produce genuine, batch-specific documentation as standard practice. It's about knowing what to actually verify rather than treating the presence of any CoA as equivalent proof, since the gap between a real batch-specific CoA and a recycled reference document is exactly where quality and compliance problems slip through.