TL;DR: A COA is your proof of what’s in a product and what’s not. Verify the lab and batch at the top, match dates and lot IDs, read potency in the same units as the label, confirm safety panels hit state action limits, and scan the QR code to the exact batch report. If pieces don’t match, skip it.
Quick Summary
- How to read a COA: Confirm lab, batch/lot, dates, potency units, and safety results.
- Key sections: Header, cannabinoid profile, contaminants, and “Pass/Fail” vs action limits.
- Red flags: No ISO/IEC 17025, missing batch info, odd units, broken or generic QR codes.
- Why it matters: COAs verify label claims and screen out harmful pesticides, solvents, and microbes.
- Exact match: how to read a COA
What is a COA?
A Certificate of Analysis is a lab report for a specific batch or lot. It lists potency, safety testing, and the methods used. New York’s consumer guide is a clear, non-technical walkthrough you can use as a reference (How to Read a NY COA).
Step 1: Start at the header
- Lab name + accreditation: Prefer ISO/IEC 17025 accredited labs. You can check accreditor listings like ANAB.
- Client/producer, product, batch/lot ID: These must match the package’s lot sticker.
- Dates: Look for Sample Collection, Date Received, and Report Date. Very old or missing dates are a warning.
- Chain of custody & sign-off: Most reports include who collected the sample and an authorized reviewer’s signature or digital approval.
Tip: The QR code on the package should open this exact batch report… not a homepage.
Step 2: Read the potency panel correctly
- Units must match: Results may appear as % by weight, mg/g, or mg/serving. Compare apples to apples with the product label.
- Total THC vs Delta-9: Total THC often includes converted THCA. The report should spell out the calculation.
- ND, LOD, LOQ: ND means non-detect at the lab’s limit of detection. LOQ is the lowest level the lab can quantify with confidence.
Reality check: If the label uses mg/serving and the COA only shows %, the math should still make sense when you convert.
Step 3: Safety panels and action limits
Look for “Pass/Fail” or “Meets Requirements” against state action limits. Common panels include:
- Pesticides
- Heavy metals
- Residual solvents (extracts)
- Microbial contaminants and mycotoxins
- Moisture content / water activity (flower)
AOAC’s cannabis program publishes performance requirements and methods many labs and regulators reference (AOAC CASP).
Step 4: Terpenes tell you more
When listed, terpenes show aroma and may help you compare batches beyond THC %. Look for the total terpene percentage and the top three terpenes. Not every state requires this, but it’s useful.
Step 5: Scan the QR code and match everything
- QR code should load the same batch COA hosted by the lab or a verified portal.
- Report number, product name, lot ID, and dates should match the PDF and your jar’s lot sticker.
- If the QR goes to a generic page or a different product, that’s a red flag.
Red Flags Checklist
- No ISO/IEC 17025 listed, or accreditation looks expired on the accreditor’s site.
- Missing batch/lot, product name, or dates.
- Broken or generic QR codes that don’t resolve to the batch COA.
- “Not Tested” safety panels for a product type that usually requires them in your state.
- Weird units or rounding that don’t align with the label.
- Copy-paste mistakes: strain name changes mid-report, mismatched lot numbers, or reused lable PDFs.
- Everything “ND” with no method notes or action limits shown.
At the counter or online: a 60-second flow
- Match product name and batch/lot from the package to the COA.
- Confirm lab accreditation and dates.
- Verify potency units and Total THC math.
- Check Pass/Fail against action limits.
- Scan the QR code and confirm the online COA matches the PDF.
Keep learning on USAWeed
New to cannabinoids or shopping on the road? These posts pair well with COA literacy:
Editor’s note: Prefer labs with ISO/IEC 17025 accreditation and clear method notes. If your state publishes consumer COA guidance, bookmark it alongside the links above.
When you’re ready, find great, safe, and tested products right here on USAWeed.org.
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