◆ Verification
How to Read a COA: What a Lab Report Actually Tells You
· 8 min read
The potency figure is the least interesting number on a lab report. It is the one everyone reads and the one least likely to hurt you if it is wrong. The panels that matter for safety sit further down, and the useful skill is knowing what a pass actually looks like — and what a report that has been made rather than measured looks like.
The panels, and what each is for
| Panel | What it answers |
|---|---|
| Cannabinoids | How strong it is, and what else is in there besides THC |
| Terpenes | What it will taste like and, loosely, how it will feel |
| Pesticides | Whether anything was sprayed on the plant that should not be inhaled |
| Residual solvents | Whether the extraction solvent was fully purged |
| Heavy metals | Lead, arsenic, cadmium, mercury — from soil or from hardware |
| Microbials | Mould, yeast and bacteria; matters most for flower |
| Mycotoxins | Toxins produced by mould, which survive after the mould is gone |
A report covering only cannabinoids and terpenes is not a safety document. It tells you what you are getting and nothing about what else came along with it. Full-panel testing is the point.
The vocabulary that trips people up
- ND — Not Detected. The lab looked and found nothing above the level its equipment can see. This is what you want across every safety panel.
- LOQ / LOD — limit of quantitation / detection. The smallest amount the method can measure reliably. "ND" always means "below this number", never "zero" in an absolute sense.
- < LOQ. Present, but too little to put a figure on. Fine on a safety panel; on potency it just means a trace cannabinoid.
- Total THC. Usually THCa × 0.877 + delta-9 THC, because heating converts THCa to THC. It is why a flower COA can show a low delta-9 number and still be potent.
- PASS / FAIL. Measured against the state's action limits, not the lab's opinion. A pass is a legal threshold, not a compliment.
Three checks that catch a fake report
Counterfeit hardware is routinely sold with a COA attached, because a PDF is easy to produce and most buyers never look past the header. These three checks are quick and catch nearly all of them.
- Does the batch on the report match the batch on your packaging? A real COA is for one specific batch. A generic report reused across a whole product line is the most common tell.
- Did you reach it yourself? Scan the QR from the packaging in your hand, or find the batch through the brand's own site. A PDF a seller messages you proves nothing at all.
- Does the lab exist, and does it confirm the report? Real reports carry a licensed lab's name, a sample ID and a date. Many labs let you verify a report number directly.
Frequently asked questions
- What does ND mean on a lab report?
- Not Detected — the lab tested for it and found nothing above the smallest amount its method can measure. Across the pesticide, solvent and metal panels, ND is exactly what you want to see.
- What is the difference between LOQ and LOD?
- The limit of detection is the smallest amount the instrument can notice; the limit of quantitation is the smallest it can put a reliable number on. Both matter because they define what ND actually means for that test.
- Which part of a COA should I read first?
- The safety panels — pesticides, residual solvents, heavy metals and microbials. Potency is a preference; those are the parts that can affect your health, and they are the reason full-panel testing exists.
- Why is Total THC higher than the delta-9 number?
- Because raw cannabis is mostly THCa, which converts to THC when heated. Total THC is typically calculated as THCa × 0.877 plus the delta-9 already present, which is why a low delta-9 figure does not mean a weak product.
- How do I know a COA is real?
- Reach it yourself rather than being sent it — scan the QR on the packaging in your hand. Then check the batch on the report matches the batch on the box, and that the lab named on it is a real, licensed one.
- Should every batch have its own COA?
- Yes. A report is a measurement of one specific batch. One PDF reused across an entire product line tells you nothing about the item you are holding, and reused reports are the most common sign of counterfeit packaging.
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