A certificate of analysis, or COA, is the lab report that is supposed to back up a product’s label. For THCA flower it contains one calculation that matters more than any other: total THC. State hemp guides, such as the ones from Missouri and Nebraska, use the same formula.
Total THC = (THCA × 0.877) + delta-9 THC. A flower that lists 25% THCA and 0.5% delta-9 works out to about 22.4% total THC. Regulators judge hemp on total THC, so a high THCA number is not a loophole in the way many labels imply.
The One Formula to Know
THCA is the raw, acidic form of THC found in the plant. Heat converts it to THC and drops some weight as carbon dioxide, which is why the formula multiplies THCA by 0.877. State guides publish the same calculation:
| Example | Math | Result |
|---|---|---|
| Retail flower: 25% THCA, 0.5% delta-9 | (25 × 0.877) + 0.5 | About 22.4% total THC |
| Hemp compliance check, from Missouri’s guide: 0.23% THCA, 0.12% delta-9 | 0.12 + (0.23 × 0.877) | 0.322%, over a 0.3% limit |
The second row shows why this matters: a sample with a tiny amount of THCA and delta-9 can still fail a 0.3% total THC test. Texas now counts THCA toward the limit for commercial hemp, and the federal restrictions scheduled for December 11 do the same, as we explain in our deadline guide. High-THCA flower is among the products most exposed.
A Seven-Point COA Checklist
- Match the batch. The batch or lot number on the report should be the same one printed on the package. A report for a different batch tells you nothing about your jar.
- Check the date. Prefer recent test dates; a report from long ago may no longer reflect the product on the shelf.
- Find the lab. A reputable lab lists its name, address and accreditation, commonly ISO/IEC 17025. Search the lab’s name and confirm the accreditation covers the tests shown.
- Look for three numbers. A cannabinoid panel should show THCA, delta-9 THC and total THC separately. Do the math yourself.
- Read the units. Percent and mg/g are both used; 1% equals 10 mg/g. “ND” means not detected.
- See the safety panels. Pesticides, heavy metals, microbial contaminants and, for extracts, residual solvents. A report with only potency leaves out half the story.
- Verify, don’t just trust. Many labs publish a QR code or lookup page. A seller who will not show the full report, only a cropped screenshot, is a red flag.
Red Flags
- Potency listed only as “THCA %” with no total THC or delta-9 line.
- A report with no batch number, no date or no lab name.
- Total THC that does not equal the formula within a small margin.
- The same report reused across many different products.
- Claims that THCA “doesn’t count” as THC for legal purposes. Agencies increasingly count it.
Before You Buy
Check what your state allows and what your carrier will ship; rules are shifting quickly. Our guide to THCA in Texas explains the state rules, and our CBD lab report guide covers the same skills for CBD products. When in doubt, ask the seller to send the full lab report before you order.