How to Read a THCA COA: What Every Number Means
A COA (Certificate of Analysis) is a third-party lab report that verifies what's actually in a THCA product. In an unregulated market, it's your only real quality check. Most buyers ignore them — here's why you shouldn't, and how to read one in under 5 minutes.
What Is a COA?
A COA is issued by an accredited, independent laboratory after testing a product sample. Reputable THCA vendors pay for these tests on every batch and publish the results publicly. The COA verifies potency, confirms Delta-9 THC compliance, and (sometimes) tests for pesticides, heavy metals, and mold.
The Most Important Numbers
THCA %
This is the headline number. High-quality THCA flower typically tests between 20–30%. Concentrates can range from 50% (wax) to 90%+ (diamonds). Be skeptical of any flower claiming over 35% — it's unlikely without test manipulation.
Delta-9 THC % (on dry weight)
This must be under 0.3% for the product to be federally legal hemp. This is the compliance number that makes THCA flower legal. Any reputable vendor will have this prominently displayed. If you can't find it, that's a red flag.
Total THC
Some labs report "Total THC" which accounts for the THCA that would convert to THC when heated: Total THC = THC + (THCA × 0.877). This number will be high (20–30%+) for quality flower. Don't confuse this with the Delta-9 compliance number.
What Good Labs Look Like
- ISO/IEC 17025 accredited — Look for this certification on the lab letterhead.
- Batch-specific — The COA should match the batch you're buying, not a generic test from 6 months ago.
- QR code or direct link — Reputable vendors link directly to the lab's portal, not a screenshot.
- Known labs: ProVerde, Infinite Chemical Analysis, ACS Laboratory, Cannalysis, SC Labs.
Red Flags to Watch For
- No COA at all — walk away.
- COA is a screenshot or PDF you can't verify directly with the lab.
- Test date is over 6 months old.
- Delta-9 THC shows above 0.3% — illegal to ship federally.
- THCA % seems impossibly high (35%+) for flower.
- Lab name isn't findable with a Google search.
Pesticide and Heavy Metal Panels
Premium vendors also test for pesticide residues and heavy metals. These panels are optional but signal quality — vendors who skip them may be cutting corners on cultivation practices.
When browsing vendors on TerpSeek, look for the COA icon on product listings — it indicates a lab report is linked directly on the product page.