How to Read a Lab Report (COA): A Hemp Shopper's Guide to the Small Print

A shop sends you a PDF. It has a logo, a stamp, a QR code and a table of numbers that looks like a train timetable for a country you have never visited. Half the rows say "ND". One says "<LOQ". Nobody explains what either means.

You nod at it the way you nod at a mechanic. Then you close the tab and buy the thing anyway.

That PDF is a certificate of analysis, or COA, and it is one of the most useful documents in the whole hemp world. It is also one of the easiest to fake, misread or quietly reuse for the wrong batch.

This guide walks you through a COA section by section, in the order we read them ourselves: what each block means, which numbers matter, and the red flags that mean it is time to email the shop. Our CBD Drops make a handy example, because its page lists exactly the figures a matching report should confirm. For the rest of our CBD range and THC alternatives, lab reports are available on request.

Read a lab report in ten seconds

Section of the COA	What you want to see	Red flag
Header	Product name and a batch number that match your pack	No batch number, or one that matches nothing you were sold
Cannabinoid profile	Each cannabinoid with a unit (%, mg/g or mg/ml)	Only a "total cannabinoids" figure, or numbers with no units
Δ9-THC and THCA	Both listed, ideally with a total THC line	THCA missing on a flower or hash report
ND / LOQ	The limits printed beside the results	"ND" everywhere and no limits anywhere
Contaminants	Heavy metals, pesticides and, where relevant, solvents and microbes, each with a limit	"Pass" with no limit and no method
The lab	Name, address, ISO/IEC 17025 accreditation number, a signature and dates	No lab name, or an accreditation you cannot look up

What a certificate of analysis actually is

A COA is a lab's report on one sample. Someone sends a sample of a specific production batch to a laboratory, the lab runs the tests it was asked to run, and it writes down what it found.

Three words in that sentence do a lot of work. One sample: the report describes what was tested, not every product a shop has ever sold. Specific batch: a new batch deserves a new report. Asked to run: a lab only reports what was ordered, so a COA with no pesticide section tells you nothing about pesticides either way. Ask whether a separate pesticide report exists for the same batch.

Think of it less as a seal of approval and more as a school report. Very informative, but only for the subjects the lab was asked to mark.

Step 1: Match the paperwork to the product

Before you read a single cannabinoid figure, check that the report belongs to the thing in your hand. This is where plenty of dodgy COAs fall over, and it takes thirty seconds.

• Product name and type. A report for "hemp extract" is not automatically a report for the vape, the oil and the gummies made from it.
• Batch or lot number. It should appear on the report and, ideally, on your packaging. No batch number means you cannot link the two.
• Dates. Look for the date the sample was received and the date the report was issued. A three-year-old report on a product that has clearly been reformulated is a souvenir, not evidence.
• Sample description. Good reports say what arrived at the lab: flower, oil, liquid, its weight or volume. If the description does not match the product, nothing below it matters much.
• Client name. The company that ordered the test. It may be the brand or its supplier; either way, it should make sense.

Step 2: The cannabinoid profile

This is the table everyone scrolls to first: a list of cannabinoids such as CBD, CBDA, CBG, CBN, Δ9-THC and THCA, each with a number. The trick is reading the unit, not just the number.

• Percent (%) is the usual unit for flower, hash and concentrates. 1% is 10 mg per gram.
• mg/g says the same thing as percent with the decimal moved: 150 mg/g is 15%.
• mg/ml is often used for oils and liquids, though many oil reports also use % or mg/g. With mg/ml, multiply by the bottle size to get the total: 400 mg/ml in a 10 ml bottle is 4000 mg.

Check which unit your report uses, then compare those figures with the label. If a bottle promises 4000 mg and the report adds up to a fraction of that, something has gone wrong somewhere between the lab bench and the marketing department.

A cannabinoid profile also tells you what kind of extract you are holding. "Full spectrum" products keep the plant's range of cannabinoids, including some THC (up to the applicable limit). "Broad spectrum" products keep the other cannabinoids and terpenes but have THC removed, usually down to a non-detectable level, which is not the same as a guaranteed zero. Our guide to full spectrum vs broad spectrum buds, listed under More reading below, goes deeper on that difference.

One caution: a profile that reports only "total cannabinoids" is a fruit salad listed as "fruit". It may be honest, but you cannot tell which fruit.

Step 3: ND, LOD and LOQ, three letters each, all the confusion

These three abbreviations cause more confusion than everything else on the page combined. Here is the plain-English version.

• LOD, limit of detection: the smallest amount the method can tell apart from nothing.
• LOQ, limit of quantification: the smallest amount the method can measure with a reliable number attached. It sits above the LOD.
• ND, not detected: the compound was not found above the LOD.
• <LOQ: it was detected, but is too low to put a reliable number on.

Why should you care? "ND" sounds like zero, but it really means "below what this method could see". A method with a very low limit saying ND tells you a lot. A method with a generous limit saying ND tells you much less. That is why a good report prints the limit next to the result, so you can judge for yourself.

If a report says ND for THC and shows no limit anywhere, you have no way of knowing how closely the lab looked. Ask for the limit.

Step 4: Δ9-THC, THCA and "total THC"

For hemp products, this is the row people care about most, and the one most easily misread.

Raw hemp contains a lot of its THC in an acid form called THCA. Heat (smoking, vaping, baking) turns much of that THCA into Δ9-THC. So a flower report showing a tiny Δ9-THC figure and a hefty THCA figure is telling you something important about what happens once it is heated.

Many reports therefore include a total THC line, calculated as Δ9-THC + 0.877 × THCA. The 0.877 is not magic; it is chemistry. THCA weighs about 358.5 g/mol and THC about 314.5 g/mol, so fully converting THCA leaves at most about 87.7% of its weight as THC. Real-world heating converts less.

Brussels, it turns out, does the same sum, so here comes the regulation bit in its smallest possible dose.

The EU's maximum levels for hemp seeds and hemp-seed products in food are set for the sum of Δ9-THC and Δ9-THCA, expressed as Δ9-THC equivalents, under Regulation (EU) 2023/915. A Commission draft sent to the Council on 1 April 2026 would apply the same approach to hemp leaves for water infusion and ready-to-drink hemp-leaf infusions; it is still a draft as of October 2026 (Council of the EU, document 7899/26). The science behind those limits comes from the European Food Safety Authority's work on Δ9-THC exposure (EFSA).

And then there are the percentages you see on labels. For farming, the European Commission says hemp varieties grown with CAP support must have a THC content below 0.3% (European Commission, hemp). That is a rule about the plant variety in the field.

Finished products can be held to separate THC limits, which vary by product type and from country to country. Many hemp products, including some of ours such as Super Silver Haze Broad Spectrum, are labelled with a "less than 0.2% THC" statement. A COA is where you check the number behind the label.

So when you read this row, ask three questions: is THCA listed as well as Δ9-THC, is there a total, and does the total sit where the label says it does?

Step 5: Contaminants, the boring section that matters most

Cannabinoid numbers get the attention. The contaminant pages are where a careful brand quietly shows its homework. Depending on the product, you may see some or all of these:

• Heavy metals, usually lead, cadmium, mercury and arsenic. Hemp is known for taking heavy metals up from the soil it grows in; it has even been studied for cleaning up contaminated land. That is exactly why this panel is worth having.
• Pesticides. In the EU, a maximum residue level (MRL) is the highest level of a pesticide residue legally tolerated in or on food or feed (European Commission, pesticide MRLs). A pesticide panel should list what was tested, the result and the limit applied.
• Residual solvents, which matter mainly for extracts, oils and vape liquids where solvents may have been used in production.
• Microbiology: moulds, yeasts and bacteria, especially relevant for flower, edibles and anything stored for a long time.

The rule here: "Pass" means nothing without a limit. Pass against what? A good report names the limit it compared against and the method it used. A report that ticks "pass" next to "heavy metals" and leaves it there is a bit like a restaurant sign saying "food: yes".

Step 6: Who did the testing

A COA is only as good as the lab behind it. The international benchmark is ISO/IEC 17025, the standard that sets the general requirements for the competence, impartiality and consistent operation of testing and calibration laboratories. As of October 2026, the current edition is ISO/IEC 17025:2017, published in November 2017 (IEC webstore, ISO/IEC 17025:2017).

Two details separate a real accreditation from a nice-looking badge:

• It can be looked up. Accreditation is granted by a national accreditation body. In Germany that is DAkkS, which runs a public database of accredited bodies. An accreditation number you cannot find anywhere is not an accreditation number you should trust.
• The scope covers your tests. Labs are accredited for specific methods. A lab accredited for, say, water testing has not automatically been assessed for cannabinoid analysis.

Also check that the report carries the lab's name and address, an authorised signature and an issue date. Independent labs have nothing to gain from hiding where they are.

Red flags worth a second look

None of these automatically means a product is bad. Each one means you deserve a better answer.

• The batch number on the report does not appear on the product, or there is no batch number at all.
• The same report appears on several different products.
• Results with no units, or a cannabinoid profile that is just one "total" figure.
• THC reported as ND with no LOD or LOQ printed anywhere.
• A flower or hash report with Δ9-THC but no THCA row.
• Contaminant panels marked "pass" with no limits and no methods.
• No lab name, no address, no accreditation number, or one you cannot verify.
• Fonts that change halfway through a table, figures that look pasted in, or a report dated years before the product launched.
• A shop that will not answer a simple "which batch is this?"

If something looks off, ask. A good seller can tell you which batch you received and which report belongs to it.

And that is it: you can read one now. No more nodding at the PDF like at a mechanic. Header, profile, limits, contaminants, lab: the train timetable finally has a route map.

The paperwork-friendly shelf

Want to put your new COA-reading skills to work? Three products whose pages state the figures or claims a matching report should back up, so you know which numbers to look for:

Our FAQ says every batch is tested by an independent laboratory, and our product pages say test results are available on request. Email support@weedorizers.com with the product name and batch number and we will find the right report. We strive to offer only products that are 100% legal throughout the EU, but rules differ between countries, so please check yours before ordering. Everything here is for adults 18+.

Lab reports, answered

What does ND mean on a lab report?

ND means not detected: the lab looked for that compound and found nothing above the lowest level its method can detect. It does not prove the amount is zero, so check the detection or quantification limit printed next to it.

What is the difference between LOD and LOQ?

The LOD (limit of detection) is the smallest amount a method can reliably tell apart from nothing. The LOQ (limit of quantification) is the smallest amount it can measure with a reliable number attached. A result reported as below the LOQ means it was detected, but is too low to put a reliable number on.

Why does a COA list THCA separately from Δ9-THC?

THCA is the acid form found in the raw plant, and heat turns much of it into Δ9-THC. Many reports therefore add a total THC line, usually Δ9-THC plus 0.877 times THCA, so you can see what the product could contain once heated.

How do I know if a testing lab is properly accredited?

Look for an ISO/IEC 17025 accreditation and the accreditation number on the report, then check it in the national accreditation body's database (in Germany that is DAkkS). Make sure the accreditation scope covers the tests on your report, not just the lab in general.

Can I ask Weedorizers for test results?

Yes. Our product pages say test results are available on request. To ask for them, email support@weedorizers.com; giving the product name and, if you have it, the batch number from your pack helps us find the right report.

More reading for the curious

• Are CBD Flowers Legal? The 2026 EU Rulebook Explained
• CBD vs THC Effects: What Each One Actually Does
• Full Spectrum vs. Broad Spectrum Buds: Which One Should You Choose?
• CBD Oil Drops: Full-Spectrum Tinctures Explained

Regulatory references checked October 2026. Thresholds and limits differ by product type and country and can change, so always check the current rules where you live. This guide explains how to read a lab report; it is not legal advice.