CBD Guides

Full panel CBD testing explained: what a lab test actually covers

By the Honest CBD Co team · 18th September 2026 · Updated 24th September 2026

A full panel CBD test checks two things: how much cannabinoid is actually in the product, and whether anything is in there that shouldn’t be. That means potency plus screens for heavy metals, pesticides, residual solvents, mycotoxins and microbial contaminants. The catch is that “full panel” has no legal definition, so the phrase on a product page tells you less than knowing what each panel actually covers. This guide walks through the panels one by one, what the FSA found when it tested 100 UK products, and how we approach testing ourselves.

TL;DR:

A genuine full panel covers cannabinoid potency plus heavy metals, pesticides, residual solvents, mycotoxins and microbial counts. Terpenes are a bonus, not a safety check.

The FSA and Fera tested 100 UK CBD products in 2022-23: only 49 matched their labelled CBD content, 45 contained less than claimed, and 27 exceeded the 1mg per container limit for controlled cannabinoids.

Hemp is a bioaccumulator, so heavy metals and pesticide residues are real risks rather than theoretical ones. Lead turned up in 41 of the 100 samples.

“ND” on a report means not detected above the lab’s detection limit, not zero, so a useful certificate states its limits and its measurement uncertainty.

The checks that matter more than a badge are the mg on the label, the price per mg, the FSA’s public product list, a full ingredient list and a brand with a real track record. Our own approach is at the bottom of this guide.

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What does full panel CBD testing actually cover?
How is CBD potency reported on a lab report?
What do the contaminant panels on a COA actually check?
Do terpene profiles and optional panels matter too?
How do you read a COA step by step?
Why does UKAS accreditation matter on a COA?
What should you check before buying a CBD product?
How Honest CBD Co approaches testing
Why the industry treats “full panel” as a marketing term, not a standard
Sources
FAQ

What does full panel CBD testing actually cover?

The term gets used loosely, so it helps to know what a proper panel includes before you give the phrase any weight.

A genuine full panel covers seven areas, and each one exists to catch a different kind of problem:

Cannabinoid potency and profile: confirms how much CBD, THC and other cannabinoids are actually present, not just what the label claims.
Heavy metals: lead, arsenic, cadmium and mercury, which hemp absorbs readily from soil and water.
Pesticides: residues from cultivation, sometimes screened across hundreds of individual compounds.
Residual solvents: leftover extraction chemicals such as ethanol, butane or hexane, depending on the method used.
Mycotoxins: toxins produced by mould, a particular risk in raw hemp material and edibles.
Microbial contaminants: bacteria, yeast and mould counts, again more relevant to raw or edible formats.
Terpenes: not a safety panel, but useful for confirming aroma, flavour and strain identity.

Some vendors put a “full panel tested” badge on a product page and only mean potency plus one or two contaminant checks. The badge tells you nothing on its own; what the panels actually measure does. Where a brand does publish its reports, checking the actual pages for batch matches tells you more than the summary graphic will.

How is CBD potency reported on a lab report?

Potency results usually appear in one of three units: milligrams per millilitre (mg/mL) for oils, milligrams per gram (mg/g) for pastes and concentrates, or percentage by weight (% w/w) for isolates and distillates. A 1000mg bottle of 10ml oil should show roughly 100mg/mL on the certificate, which is the same thing as 10%. If the maths doesn’t match what’s printed on the packaging, that’s a genuine problem rather than a rounding quirk. Our guide to CBD oil strengths and mg per drop covers the conversions in detail.

Look for both a total CBD figure and a breakdown of individual cannabinoids, including CBDA, CBG and CBN where relevant. Total CBD is usually calculated from CBD plus CBDA using a conversion factor, so the two figures should sit close together, not miles apart. For full-spectrum products, THC and THCA get reported separately too, and this is where measurement uncertainty actually matters. In the UK the limit for a finished product is 1mg of controlled cannabinoids per container, not a percentage, so a lab result has to be converted into milligrams for the whole bottle. A result sitting close to that line with a stated uncertainty could genuinely be above or below it. A responsible lab states that uncertainty rather than hiding it.

What do the contaminant panels on a COA actually check?

This is where a full panel earns its name, and where the FSA and Fera’s 2022-23 survey of UK products makes uncomfortable reading for anyone who assumes contaminants are a theoretical risk.

Heavy metals get tested because hemp is a bioaccumulator. It pulls lead, arsenic, cadmium and mercury straight out of contaminated soil and concentrates them in the plant. Lead was the most frequently detected metal in the FSA’s sampling, found in 41 of the 100 products, which is exactly why this panel isn’t optional.

Pesticide screening varies enormously between labs. Some run a basic panel of a few dozen compounds; more thorough providers screen for several hundred, covering everything from common agricultural sprays to compounds banned outright in food production.

Residual solvents matter mainly for products made with hydrocarbon or ethanol extraction. CO2 extraction carries less solvent risk, but any extracted product should still show a clean solvent panel confirming ethanol, butane, propane and similar compounds sit below safe limits. Our Whole Plant Paste is made with supercritical CO2 extraction and is solvent-free.

Mycotoxins and microbial screens matter most for raw hemp flower and edible formats, where mould and bacterial growth have the clearest route to affecting a consumer.

The scale of the problem in the UK market is worth stating plainly. Fera analysed 100 CBD products bought online in England and Wales for the FSA, using UKAS-accredited methods for most of the work, and found that only 49 matched their labelled CBD content, while 45 contained less CBD than claimed. Pesticide residues turned up in 21 samples, mycotoxins in 24, and 27 of the 100 products exceeded the 1mg per container limit for controlled cannabinoids. That’s not a fringe finding from an obscure lab. It’s a government-commissioned survey of products already on sale in the UK.

When you see “ND” (not detected) on a contaminant table, that’s conditional on the lab’s limit of detection (LOD) or limit of quantitation (LOQ), not proof of zero presence. A certificate without stated LOD/LOQ values is far less useful, because you can’t judge how sensitive the test actually was.

Do terpene profiles and optional panels matter too?

Terpene testing isn’t a safety check. It confirms aroma compounds and helps verify a product’s strain identity, which matters more for flower than for capsules or isolate oils. Some certificates also include optional screens for polycyclic aromatic hydrocarbons (PAHs), PCBs or dioxins, generally reserved for concentrates made through solvent-heavy extraction or products claiming higher purity grades. If a certificate doesn’t mention these, it usually just means the lab didn’t run them, not that the product failed them. Check the panel list on the report itself rather than assuming.

How do you read a COA step by step?

A certificate of analysis only tells you something if you read past the front page. If you have one in front of you, here is how to get the most from it.

Match the basics. Confirm the product or material name, the batch ID and the test date on the certificate correspond to what you were sent.
Read the cannabinoid table. Check the reporting units, look for a total CBD figure alongside individual cannabinoids, and note any stated measurement uncertainty.
Check every contaminant table. Look for results flagged above action limits, and for “ND” results confirm the LOD/LOQ is actually stated in the footer.
Confirm lab accreditation and method statements. A credible certificate names the testing method used for each analyte, not just a pass/fail summary.

A genuine full panel usually runs to several pages once every contaminant table is included. A single cropped summary graphic on a product page normally means only the potency panel was run, however impressive the badge next to it looks.

Why does UKAS accreditation matter on a COA?

UKAS accreditation to ISO 17025 means a lab has been independently assessed for technical competence, calibration standards and quality management, not just that it owns the right equipment. It’s the accreditation behind most of the government-commissioned testing in the FSA and Fera survey, and it’s the same standard Eurofins references for its cannabinoid and contaminant testing across UK and EU food and supplement categories.

A certificate should state the method used for each analyte and show LOD/LOQ figures alongside measurement uncertainty for potency results. Without that detail you have a number with no way to judge how reliable it is. Not every contaminant on a report is necessarily tested under UKAS accreditation either. Even in the FSA’s own survey, the residual solvent and some mycotoxin analyses fell outside the accredited scope while the cannabinoid panel sat inside it, so the footer or annex of a certificate is where you find out which analytes carry accredited status.

What should you check before buying a CBD product?

Testing badges are the least reliable signal on a product page, as the FSA survey showed. The checks that actually separate a good product from a poor one take a minute and don’t need a lab report in your hand.

The CBD content is stated in milligrams, not just a percentage. A 10ml bottle at 10% is 1000mg, which works out at about 5mg per drop. A label that gives only a percentage, or says “hemp oil” with no CBD figure at all, is the classic sign of a product that contains very little.
The price per milligram makes sense. Divide the price by the mg on the label. Our Full Spectrum CBD Oil at £25.99 for 1000mg is about 2.6p per mg; anything far above 5p a mg is paying for packaging, and anything absurdly cheap is usually short on CBD.
Every ingredient is listed. You should be able to see the carrier oil and anything else in the bottle. Our product pages list every ingredient, down to the carrier and the capsule shell.
The THC position is clear. A full spectrum product should say plainly that it sits within the UK limit of 1mg per container, and an isolate product should say it is THC-free.
The FSA keeps a public list of CBD products. CBD food products sold in England and Wales are supposed to be linked to a novel food application on the FSA’s public list. It is one of the few genuine registers this market has, and worth knowing about.
The brand is a real, contactable business with a track record. A UK address, a person who answers the email, and independent reviews going back years. We have traded from Bolton since 2018 and are rated Excellent on Trustpilot across more than 700 reviews.
The brand can tell you where its CBD was tested. A good seller knows the answer straight away and is glad to share the certificate.

These checks are the backbone of our companion guide, how to spot fake CBD oil in the UK, which works through each one in about a minute.

How Honest CBD Co approaches testing

We are a husband-and-wife business in Bolton and we have made our own CBD products in small batches since 2018. The raw CBD we use is lab-tested at source before it reaches us, and we are happy to share the certificates of analysis for that material. What we then do with it is simple by design: our Whole Plant Paste is the raw CO2 extract with nothing added, our Full Spectrum CBD Oil is that extract and our distillate in organic hemp seed oil (10% for £25.99, 20% for £37.99, 10ml bottles), and our Full Spectrum CBD Capsules hold the same three hemp ingredients in a plant-cellulose shell at 40mg, 80mg or 120mg per capsule, from £19.99. Short ingredient lists leave very little room for anything the panels above are looking for, and the mg on every label is the mg in the product. If you want to avoid THC altogether, our Pure CBD Isolate Oil starts at £14.99 for 1000mg.

Why the industry treats “full panel” as a marketing term, not a standard

Here’s the uncomfortable bit nobody in this industry says out loud: “full panel” has no fixed legal definition. It’s a phrase labs and brands borrowed from clinical diagnostics, and there’s no regulatory body policing what it must include on a CBD product. That’s precisely why the FSA’s finding that only 49 of 100 products matched their CBD claim didn’t come from obscure back-street operators. Some were established, well-marketed brands whose testing badges looked perfectly convincing.

The gap that matters most isn’t between good labs and bad labs. It’s between a badge and a brand. A testing graphic tells you what one sample did on one day. A brand that has sold the same products to the same customers for eight years, lists every ingredient, states every strength in milligrams and answers its own emails is telling you something a badge can’t. Choose on the track record, and treat the testing vocabulary as useful background rather than the deciding factor.

Richard, Honest CBD Co

This article is general information, not a substitute for advice from a qualified doctor. Consult a qualified healthcare professional about your own circumstances before acting on anything here.

Sources

FAQ

Can I fail a drug test if I use CBD?

Standard workplace drug tests screen for THC metabolites, not CBD itself, so repeated use of a full-spectrum product carries a small but real risk of a positive result. Choosing a THC-free isolate product such as our Pure CBD Isolate Oil removes this risk if drug testing is a concern.

What shows up in a 5 panel drug test?

A standard drug test typically screens for THC, cocaine, opiates, amphetamines and PCP, though exact panels vary by employer and testing provider. It does not screen for CBD directly, only for THC metabolites, which is why full-spectrum CBD use can occasionally trigger a positive result on the THC line.

Can CBD oil be detected on a drug test in the UK?

CBD itself isn’t the target of standard drug tests, but the trace THC in full-spectrum oil can be. Our guide to how long CBD lasts and detection times goes into the detail.

Can CBD drinks be detected on a drug test?

CBD drinks made with isolate typically contain no detectable THC, so they shouldn’t trigger a positive test. Drinks made with full-spectrum extract carry the same trace THC risk as any other full-spectrum product, so if the label says full spectrum, assume there is some THC in it.