How to Read a CBD Lab Report: THC Results, Batch Testing and Certificates of Analysis

"Lab tested" on a CBD label is a claim. A certificate of analysis, or COA, is the evidence, and only if it matches the product in your hands. This guide shows what a COA is, which numbers deserve your attention, why "ND" for THC is a statement about an instrument and not about the bottle, and how to tell when a report is missing the information that would make it useful. It also ends with a checklist you can use on any brand.

What a certificate of analysis is

A COA is a report from a laboratory that lists test results for a specific sample. For a CBD product, that usually includes potency (how much CBD and other cannabinoids), and may include screens for heavy metals, pesticides, residual solvents, microbes and mycotoxins. A COA is only as strong as the lab behind it and the sample it tested. Many brands pay an outside lab. Some test in-house. Neither is automatically wrong, but you should know which one you are reading.

The reason to read COAs is not academic. A 2017 study in JAMA bought 84 CBD products sold online and found that nearly 70 percent contained more or less CBD than the label said, and some products marketed as THC-free had detectable THC. Labels alone do not settle the question.

Step 1: Match the report to your product and batch

• Product name and size. A report for a 900 mg gummy does not describe a 1,800 mg oil.
• Batch or lot number. It should match the number printed on your container or the number the retailer lists for the item you are buying. If the retailer posts one report for a whole product line, ask whether the batch is current.
• Sample and report dates. A report from years ago may not describe a current batch.
• Laboratory name and contact details. You should be able to tell who ran the test and how to reach them. Accreditation to ISO/IEC 17025, the general standard for testing laboratories, is a useful sign but not a guarantee.

Some retailers organize reports by product name with batch identifiers that open individual PDFs. NuLeaf Naturals, for example, posts a lab report library grouped by product with batch IDs and a batch search tool. When CannaWize reviewed that page on October 28, 2026, it did not name a testing laboratory or method on the listing page itself. Those details, if present, are inside the individual PDFs, and CannaWize has not matched a current-lot PDF to each product on our site. We say so on every product we list.

Step 2: Read the potency table

Potency results tell you how much of each cannabinoid the sample contained. Look for these points.

• Units. Results appear as percent by weight, milligrams per gram, or milligrams per milliliter. For an oil, you need mg/mL times the volume of the bottle to get the amount in the container. For a gummy, you need milligrams per gummy.
• CBD versus label. Compare the lab result with the label claim. A gap of 10 percent either way is common as a rough yardstick in published studies, but a large gap deserves a question.
• Other cannabinoids. Broad-spectrum products should show other cannabinoids and no THC. Isolates should show essentially only CBD.

Step 3: Total THC, delta-9 THC and THCA

THC appears in several forms. Delta-9 THC is the intoxicating compound people usually mean. THCA is its raw acid form, which converts to delta-9 THC when heated. A report that lists only delta-9 THC can understate what you could be exposed to if the product also contains THCA.

The regulatory shorthand is "total THC." USDA's hemp rules (7 CFR Part 990) measure total THC after decarboxylation, which adds delta-9 THC to 87.7 percent of the THCA value to account for the weight lost when the acid group comes off. Federal law as amended in 2025 moves the hemp definition to a total THC standard. A COA that reports only delta-9 THC, or that reports THCA separately and does not state a total, leaves you doing arithmetic or guessing.

Step 4: Detection limit, quantitation limit and what "ND" means

Every test has limits.

• Limit of detection (LOD): the lowest amount the method can reliably tell apart from nothing. "ND" or "not detected" means the result was below this level.
• Limit of quantitation (LOQ): the lowest amount the method can measure with acceptable accuracy. A result such as "<LOQ" means the compound was likely present but too faint to put a number on.

Here is why that matters. Suppose a report shows THC as "<LOQ" with an LOQ of 0.01 mg/mL in a 30 mL bottle. The most THC the bottle could hold while still reading "<LOQ" is about 0.3 mg. If the LOQ were 0.02 mg/mL, the ceiling would be about 0.6 mg. This is hypothetical arithmetic for illustration. It shows why the limit, not just the word "ND," decides how much you can conclude. The 2025 federal change excludes final products with more than 0.4 mg of total THC and similar cannabinoids combined per container, which is a threshold small enough that a coarse detection limit could not settle it. The federal term "container" and the list of cannabinoids that count are still awaiting FDA input as of the Congressional Research Service update of September 28, 2026, so no one can responsibly call a product "compliant" from a COA alone.

Step 5: Contaminant panels

A potency-only report tells you nothing about safety. A fuller report adds panels, each with a pass or fail against a stated limit.

• Heavy metals: lead, cadmium, arsenic and mercury, because hemp absorbs metals from soil.
• Pesticides: a list of compounds screened, with results and limits.
• Residual solvents: leftover extraction solvents such as ethanol or hydrocarbons.
• Microbial contamination: yeast, mold, total aerobic count and specific pathogens.
• Mycotoxins: toxins produced by molds, such as aflatoxins.

Be wary of a badge that says "no pesticides, heavy metals or mycotoxins" with no linked panel. A statement that a product is free of contaminants is not the same as a table of results with limits and a method.

Product-level versus batch-level claims

A COA describes one batch. A brand may test a representative batch and apply the finding to everything it sells, or it may test every lot. Neither is a guarantee about your bottle unless the batch matches. If a retailer lists a single report for a product that has been reformulated or re-sourced, treat it as a starting point and ask for the current lot.

How to recognize missing information

• No batch number, or a batch number that does not match the product you are buying.
• No laboratory name, no method and no date.
• THC listed as "ND" with no detection limit.
• Delta-9 THC reported but not THCA or total THC.
• Potency reported in percent with no way to get to milligrams per container.
• A pass/fail summary with no underlying table.
• A report for a different product in the same line.

Practical buyer checklist

1. Find the COA before you buy, and open it.
2. Confirm product name, size and batch match.
3. Note the lab, the test date and the method.
4. Compare potency with the label.
5. Check delta-9 THC, THCA and total THC, plus the detection and quantitation limits.
6. Look for panels for metals, pesticides, solvents, microbes and mycotoxins.
7. Confirm the product ships to your state, because retailers list restrictions by product. See CBD shipping restrictions by state.
8. If any answer is missing, ask the seller in writing. If they cannot supply it, consider a different product.

What CannaWize does with COAs

Before a CBD product appears in our shop, a person records the batch, laboratory, test date, method, detection and quantitation limits and whether the report matches the current lot. If any of that is missing, the product stays out. We do not run our own tests, and a COA review does not certify that a product is legal in your state or compliant with federal rules. The CBD lab testing page lists the fields we track, and the NuLeaf Naturals partner profile explains how that applies to our affiliate partner. CannaWize may earn a commission when you buy through links to partner stores.

Affiliate disclosure: CannaWize is a FlexOffers affiliate of NuLeaf Naturals and may earn a commission if you buy through links on this page, at no extra cost to you. CannaWize does not sell these products or process orders. You buy from the retailer, which sets prices and handles shipping and returns.

Health and legal information: This page is educational and is not medical or legal advice. The FDA has not approved CBD products other than the prescription drug Epidiolex, and it says CBD cannot be sold as a dietary supplement or added to food in interstate commerce. Statements by manufacturers have not been evaluated by the FDA. Talk with a doctor or pharmacist before using CBD, especially if you take medication, are pregnant or breastfeeding, or are subject to drug testing. Shipping restrictions vary by product and destination, and laws are changing.