Short answer: a Certificate of Analysis, or COA, is the third-party lab report that tells you what's actually in your hemp flower β how potent it is, whether it's legally compliant, and whether it's free of contaminants. Learning to read one takes about five minutes and is the single best habit for buying hemp with confidence. This guide walks through each section so the numbers stop looking like a wall of chemistry.
If you've ever scanned a QR code on a package and landed on a dense PDF full of acronyms, this is for you.
What a COA is (and why it exists)
A COA is a report produced by an independent, licensed testing lab β not by the brand selling the product. That independence is the whole point. It verifies three things: how much of each cannabinoid the flower contains, whether it meets the legal definition of hemp, and whether it's clean of things you don't want to inhale, like mold, pesticides, and heavy metals.
Reputable hemp is tested at every stage, and the COA is where that testing becomes visible to you. Our broader explainer on what lab testing tells you about hemp products covers the why; this post is the how-to.
Start at the top: is the lab legit?
Before you read a single number, check who ran the test.
Look for the lab's name, contact information, and β most importantly β accreditation. The gold standard is ISO/IEC 17025, the international standard for testing laboratories. A lab holding that accreditation has had its methods, equipment calibration, and quality controls independently verified. You also want to see a sample date and a batch or lot number that matches the product in your hand. A COA for a different batch, or one with no date, isn't telling you about your flower.
Red flags: no lab name, no accreditation, no batch number, or a report that looks like it was typed up in a word processor rather than generated by lab software.
The potency section: THCA, Delta-9, and Total THC
This is the part most people came for, and it's where the acronyms cluster. Three numbers matter most.
THCA
THCA is the raw, unheated cannabinoid that makes up most of the "strength" in hemp flower. If a report says 28% THCA, that means 28% of the flower's dry weight is THCA. This is usually the biggest number on the sheet and the one brands feature. THCA isn't intoxicating until it's heated β the conversion is called decarboxylation, which our decarboxylation explainer breaks down.
Delta-9 THC
This is the legally regulated cannabinoid. Under federal hemp rules, this number is what has historically kept a product on the legal side of the line. On a compliant hemp COA you'll see Delta-9 THC listed well below the legal threshold, often reported as a small fraction of a percent. The relationship between THCA and Delta-9 is the core of our post on THCA vs. Delta-9 THC if you want the full picture.
Total THC
Total THC is the number that estimates the maximum THC you'd get if all the THCA converted to THC when heated. Labs calculate it with a standard formula:
Total THC = Delta-9 THC + (THCA Γ 0.877)
That 0.877 factor accounts for weight lost when THCA sheds its acidic part during heating. So 28% THCA works out to roughly 24.6% potential THC once you apply the conversion. Total THC is worth watching closely because it's becoming the number regulators focus on β federal law is shifting toward defining hemp by total THC rather than Delta-9 alone. Reading it now is a good habit.
The contaminant panels: where PASS matters
Potency tells you how strong the flower is. The contaminant panels tell you whether it's safe. Depending on the state and lab, a full COA may screen for:
- Microbials β harmful microbes like E. coli and Salmonella.
- Heavy metals β lead, arsenic, cadmium, and mercury, which plants can pull from soil.
- Pesticides β residues from cultivation.
- Residual solvents β relevant mainly to concentrates and extracts, not raw flower.
- Mycotoxins β toxins produced by certain molds.
For each of these, you want to see the result marked PASS, or the individual compounds marked ND. More on those two terms next.
For flower specifically, look for moisture content and water activity. These aren't safety hazards on their own, but they tell you whether the flower was cured and stored properly. Water activity in a healthy range means the flower is far less likely to grow mold before you finish it.
Decoding the abbreviations
A few shorthand terms show up on nearly every COA:
- ND β Not Detected. The lab tested for a compound and didn't find it at or above its detection floor. On contaminant panels, ND is exactly what you want.
- LOD / LOQ β Limit of Detection / Limit of Quantitation. The lowest amounts the instrument can reliably detect or measure. "ND" is meaningful relative to these limits.
- < (less than). A result like "<LOQ" means the compound is present in an amount too small to measure precisely β effectively trace.
- mg/g and %. Two ways of expressing the same concentration. Percent is dry weight; mg/g is milligrams per gram. (1% equals 10 mg/g.)
Putting it together: a quick checklist
When a COA lands in front of you, run through this in order:
- Legit lab? Named, accredited (ISO/IEC 17025), with a batch number and recent date that match your product.
- Potency makes sense? THCA and Total THC line up with what the product claims.
- Compliant? Delta-9 THC and Total THC sit within legal limits.
- Clean? Every contaminant panel reads PASS or ND.
- Well-cured? Moisture and water activity are in a healthy range.
If all five check out, you're looking at flower a brand is willing to stand behind with data. If a COA is missing, out of date, or from an unnamed lab, treat that as the answer to your question.
Every product in our flower collection is backed by third-party lab testing, so you can practice reading a real COA on flower you're actually considering. Once you've read a few, the acronyms turn into a fast, reliable gut-check β and that's the whole goal.
Chubby Smoke products are lab-tested and intended for adults 21+. This article is educational and is not legal or medical advice. These statements have not been evaluated by the FDA.
