How to Read a CBD Certificate of Analysis: A Step-by-Step Guide
How to Read a CBD Certificate of Analysis: A Step-by-Step Guide
A COA is your proof that a CBD brand is telling the truth. Here's exactly what to look for — cannabinoid profiles, contaminant panels, red flags — with annotated examples from real MirthPlus lab reports.
You've probably seen the phrase "third-party tested" on CBD products. It sounds reassuring. But what does it actually mean — and how do you verify it yourself?
The answer is a Certificate of Analysis, or COA. It's a lab document that shows exactly what's in your CBD product — what cannabinoids are present, at what concentrations, and whether any contaminants were detected. Every reputable CBD brand publishes them. Many don't.
Reading a COA doesn't require a chemistry degree. Once you know what the sections mean and what to look for, it takes about two minutes — and it will tell you more about a brand's integrity than any marketing copy ever could.
This guide walks you through every section, shows you what a clean COA looks like, and tells you exactly which red flags should make you close the tab and shop somewhere else.
"If a brand is proud of their testing, they'll make the COA easy to find. If they hide it or don't have one — that's your answer."
What a COA Is — and What It's NOT
A Certificate of Analysis (COA) is an official document from an independent laboratory confirming the results of testing performed on a specific product batch. Think of it as a report card — for the product, not the brand.
A COA tells you:
- What cannabinoids are present and in what amounts
- Whether THC is at or below legal limits
- Whether contaminants like pesticides, heavy metals, solvents, or microbials were detected
- Which batch the test corresponds to
- Which lab ran the test and when
A COA does not tell you:
- Whether the product works for your specific needs
- Whether the brand's other batches are equally clean
- Whether the tested sample matches what's on the shelf today
That last point is why batch-matching matters — which we'll cover in the red flags section.
COA = Certificate of Analysis. A third-party lab document verifying what's in a specific product batch. It is not a government approval, a safety guarantee, or a marketing document — it is a factual test result.
Who Runs the Test — and Why It Matters
Not all lab tests are equal. The gold standard for CBD testing is a lab accredited under ISO/IEC 17025 — an international standard for testing and calibration laboratories. ISO 17025 accreditation means the lab has been independently audited and verified to produce accurate, reproducible results.
Look for ISO 17025 accreditation
It should be stated on the COA itself. If you don't see it, search the lab's name + "ISO 17025 accredited" to verify. Labs like ProVerde, SC Labs, Steep Hill, and ACS Laboratory are well-regarded ISO 17025 facilities in the US.
Confirm it's a third-party lab — not in-house
The lab name should be different from the brand. "Tested by MirthPlus Internal Lab" is not a COA — it's a marketing claim. Legitimate COAs come from labs that have no financial stake in the result.
Check the test date
COAs have an expiration date in practice, even if not stated. A COA from three years ago doesn't reflect the product on the shelf today. Look for testing within the last 12 months for the specific batch you're buying.
Reading the Cannabinoid Profile
This is the section most people look at first — and it contains some of the most important information. The cannabinoid profile tells you exactly which cannabinoids were detected and at what concentration.
Here's what you'll typically see and what each means:
CBD (Cannabidiol)
This is the primary active compound. The mg amount shown should match (within a reasonable margin) what's on the product label. A 500mg CBD product should show approximately 500mg of CBD in the total batch or per serving calculation. A variance of ±10% is generally acceptable in the industry; larger discrepancies are a concern.
THC (Delta-9 Tetrahydrocannabinol)
Federal law requires hemp-derived CBD products to contain no more than 0.3% THC by dry weight. On a COA, this will appear as a percentage. For a THC-free claim (like all MirthPlus products), you want to see THC listed as "ND" (Not Detected) or below the limit of quantification (LOQ).
Other Cannabinoids
Full-spectrum products will show a broader profile including CBG, CBN, CBC, and others. Broad-spectrum products should show these minor cannabinoids present but THC at ND. Isolate products should show only CBD, with everything else at ND.
"Non-detect" (ND) means THC was tested for and not found above the lab's limit of detection. This is the strongest form of the THC-free claim — it means the test equipment couldn't find it, not just that it was below 0.3%.
At MirthPlus, every product in our store — both Mirth Originals and our curated NAYSA selections — is THC-free. Our COAs show ND for THC across the board.
Contaminant Testing — The Most Important Section
The cannabinoid panel gets the attention, but the contaminant panel is where your safety actually lives. A product can have exactly the right CBD concentration and still be harmful if it contains pesticide residue, heavy metals, or microbial contamination.
A complete COA should include testing for all four contaminant categories:
🌿 Pesticides
Hemp is a bioaccumulator — it pulls compounds from the soil, including pesticides. A clean COA will show pesticide residues as ND (Not Detected) or below action limits set by state cannabis regulations. Look for panel coverage of at least 60–100 pesticides. A panel testing only 5–10 compounds is not comprehensive.
⚙️ Heavy Metals
The four metals to look for: Lead (Pb), Arsenic (As), Cadmium (Cd), and Mercury (Hg). Each should be listed with a result (in µg/g or ppm) and a corresponding action limit. ND is ideal. Any result at or near the action limit warrants scrutiny.
🧪 Residual Solvents
CBD is extracted from hemp using solvents like ethanol, butane, CO₂, or propane. Trace amounts may remain. A clean product will show solvents at ND or well below limits. This panel matters most for extracts and concentrates; it's less critical for hemp seed oil products.
🦠 Microbials
Bacterial and fungal contamination can occur during harvesting or processing. Look for testing of Total Yeast & Mold (TYMC), Total Aerobic Count (TAMC), and ideally E. coli, Salmonella, and Aspergillus species. All should pass.
🔍 Want to see a real MirthPlus COA? Every batch is published — no login required.
View Our COAs →Red Flags That Should Stop You Cold
Most people scan a COA looking for green checkmarks. But the real skill is knowing what to look for when something's wrong. Here are the six red flags that should make you pause — or walk away entirely.
| Red Flag | Why It Matters | What to Do | |
|---|---|---|---|
| 🚨 | Batch number doesn't match your bottle | The COA could be from a different — potentially cleaner — batch than the one you received. | Stop. Contact the brand. Demand the COA for your specific lot number. |
| 🚨 | In-house testing only | A brand testing their own product has a financial interest in the result. This isn't third-party — it's marketing. | Do not accept. Only ISO 17025 accredited external labs count. |
| ⚠️ | Missing contaminant panels | A COA showing cannabinoid profile only (no pesticides, metals, microbials) is incomplete. You have no safety data. | Ask for the full panel. If they don't have one, this is a significant trust failure. |
| ⚠️ | COA is more than 12–18 months old | Products change. Batches rotate. An old COA doesn't tell you about the product you're holding today. | Ask for a current COA. Reputable brands test every batch. |
| ⚠️ | CBD amount differs from label by >15% | You're either getting less than you paid for — or the brand's quality control is inconsistent. | This is a labeling accuracy issue. Consider it a trust signal about the brand overall. |
| ⚠️ | No COA available at all | This is the biggest red flag of all. There is no legitimate reason for a reputable CBD brand to not publish COAs. | Walk away. Full stop. |
If a brand says "our products are tested" but doesn't publish the actual COAs on their website — that's not transparency. That's a claim without proof. At MirthPlus, every COA is publicly available with no login, no hoops, no exceptions.
How to Find MirthPlus COAs — and What You'll See
Every product sold on MirthPlus.com — whether it's a Mirth Original or one of our carefully selected NAYSA formulations — has a published COA. Here's how to access them:
Go to the product page
Every MirthPlus product listing includes a direct link to the current COA. You'll find it in the product description, typically labeled "View Certificate of Analysis" or "Lab Results."
Visit our COA hub
We maintain a central transparency page at mirthplus.com/transparency where you can browse COAs by product and batch number. No account required.
Match the batch number
Check the lot/batch number on your product against the COA. They should match. If they don't — or if you have any questions — our team is reachable directly. We'll sort it out.
Full cannabinoid profile — including CBD potency match to label and THC confirmed at ND.
Complete contaminant panel — heavy metals (4 compounds), pesticides (87+ compounds), residual solvents, and microbials.
ISO 17025 accredited lab — tested by an independently audited third-party facility.
Current batch-specific results — not a generic document. Your product, your batch.
We're proud of what our COAs show. That's exactly why we make them easy to find.
📖 CBD Myths We're Done Pretending Are Complicated — our May 7 post that tackles the most common misconceptions head-on.
📖 Relief Rub: The Ingredient Breakdown — how we formulate, and what the testing shows for our flagship topical.
Your COA questions, answered plainly
A complete CBD lab report (COA) should show: (1) a full cannabinoid profile including CBD potency and THC level; (2) heavy metals testing for at least lead, arsenic, cadmium, and mercury; (3) pesticide residue testing covering at least 50–100+ compounds; (4) residual solvent testing; and (5) microbial testing for yeast, mold, and bacteria. If any of these panels are missing, the COA is incomplete. A clean, reputable COA will also include the lab name, ISO accreditation number, test date, and a batch/lot number matching the product.
The most reliable way to assess safety is to review the product's COA from an ISO 17025 accredited third-party lab. Look for: all contaminant panels passing (ND for heavy metals, pesticides, microbials), THC at or below 0.3% (or ND for THC-free products), and a batch number that matches your bottle. Beyond the COA, consult your healthcare provider — especially if you take medications, are pregnant or nursing, or have a health condition. CBD can interact with certain drugs that are metabolized by liver enzymes.
"Third-party tested" means the product was sent to an independent laboratory — one with no financial relationship to the brand — for analysis. The key word is independent. In-house testing (a brand testing their own products) is not third-party, regardless of how it's described in marketing copy. Legitimate third-party testing produces a COA from an external, ideally ISO 17025 accredited, laboratory. You should be able to view the actual lab document, not just a brand's summary of it.
Five quick checks: (1) Can you find their COAs on the website without logging in or asking? (2) Do the COAs come from an ISO 17025 accredited lab, not an in-house facility? (3) Does the batch number on the COA match the product you received? (4) Does the COA include contaminant panels — not just cannabinoid potency? (5) Is the COA recent — within the last 12–18 months for the specific batch? A brand that makes all five easy is doing it right. A brand that makes any of these difficult has something to hide.
ISO/IEC 17025 is an international standard for testing and calibration laboratories. Labs with this accreditation have been independently audited to verify that their testing methods, equipment, and processes are accurate and reproducible. For CBD testing, it means the results you're reading were produced by a facility held to a rigorous, independently verified standard — not just a lab that bought some equipment and set up shop. When a COA shows ISO 17025 accreditation, it's a meaningful quality signal. When it doesn't, the testing standard is unknown.
Best practice is per-batch testing — meaning every new production run has its own COA. At minimum, COAs should be updated annually. If a brand only has one COA for a product regardless of batch, or the dates are more than 18 months old, you're not looking at current testing data. At MirthPlus, we test every batch and publish each COA with the corresponding lot number so you can verify your specific product.
Ready to shop with confidence?
Every MirthPlus product comes with a published COA. No hoops. No login. Just honest results from an accredited lab.