Reading Cannabis Lab Reports
A certificate of analysis, often shortened to COA, records what a laboratory found in a tested sample. It can help you compare a product's label with its measured contents. It cannot tell you exactly how the product will affect you, and it is not a medical recommendation.
Match the report to the product
Start with the report's identification details. A report for a different batch or product does not verify the one in front of you.
- Product and batch
- Compare the product name, batch or lot number, and sample description with the package. Flower, oil, and finished edibles are different sample types.
- Laboratory
- Look for the laboratory's name, report identifier, and any license information. Where licensing applies, check the lab against the relevant regulator's records.
- Dates
- Check when the sample was collected, received, and tested. A test describes the sample at that time; it does not track changes during later storage.
- Tests performed
- Read the full report. A cannabinoid potency panel is not the same as a complete set of contaminant tests.
For a state-specific example, California's Department of Cannabis Control explains laboratory testing and certificates of analysis. Requirements differ by jurisdiction and product type.
An example potency report
The numbers below are made up to illustrate how to read a flower report. They are not results for a Hytiva product or a recommended potency.
| Result | Percent | Equivalent mg/g |
|---|---|---|
| THCA | 20.00% | 200.0 mg/g |
| Delta-9 THC | 1.00% | 10.0 mg/g |
| Calculated total THC | 18.54% | 185.4 mg/g |
| CBD | 0.20% | 2.0 mg/g |
Total THC is calculated from the THC and THCA measurements. It is not an additional ingredient to add to those rows.
THC, THCA, and total THC
THCA converts to THC when heated. A common reporting calculation accounts for the mass lost during that conversion:
Total THC = delta-9 THC + (THCA × 0.877)
For the example above, 1.00% + (20.00% × 0.877) = 18.54%. This estimates potential THC by weight. It does not measure how much THC reaches your bloodstream or account for every loss during heating and use.
Always check the report's calculation notes. California's testing regulations (PDF) provide an example of the 0.877 conversion factor. A total THC value should not be confused with a simple sum labeled “total cannabinoids.”
Units and serving sizes
- Percent by weight
- One percent means 10 milligrams per gram of material. The example's 20% THCA is equivalent to 200 mg/g.
- mg/g and mg/mL
- Milligrams per gram describes concentration by mass; milligrams per milliliter describes concentration by volume. They are not interchangeable without additional information.
- Per serving
- For an edible, distinguish the amount per serving from the amount in the package. A package with 100 mg THC divided into 10 equal servings contains 10 mg per serving. This is an arithmetic example, not dosing advice.
- Dry-weight basis
- A dry-weight result excludes moisture from the weight used in the calculation. Compare reports using the same basis rather than assuming all percentages were calculated alike.
Terpene results
A terpene panel lists the compounds tested and their measured amounts. Compare individual results and units, and check which terpenes the lab included in its total. Two labs may not test the same panel.
The profile can help describe aroma, but a terpene percentage is not proof of a particular mood, medical benefit, or experience. Our Cannabis Terpene Guide explains the individual compounds.
Detection and reporting limits
- ND / not detected
- The compound was not detected above the method's stated detection or reporting threshold. It does not necessarily mean that absolutely none is present. Check the report's legend.
- LOD
- The limit of detection is the lowest level the method can distinguish from background under its specified conditions.
- LOQ
- The limit of quantification is the lowest level the method can measure with its specified accuracy and precision. A result below LOQ may not support a reliable numerical amount.
- Not tested
- This means no result was provided for that test. It should not be treated as “not detected” or “passed.”
FDA's analytical procedure validation guidance provides technical background on how measurement methods are evaluated.
Contaminant testing
Depending on the product and jurisdiction, testing may cover pesticides, heavy metals, residual solvents, microbes, and other contaminants. Read the named tests, results, units, and applicable limits. A “pass” applies to those tests and limits; it does not mean that every possible contaminant was checked.
FDA's quality guidance for cannabis clinical research addresses product quality in drug development. It is not an FDA certification program for retail cannabis lab reports.
What a report cannot establish
A report describes a tested sample, with the limitations of its sampling and methods. It does not establish medical effectiveness, FDA approval, or freedom from impairment. A passing report also cannot predict your response to the product.
CDC explains that effects vary with the amount used, previous experience, method of use, and other substances. Read its cannabis FAQs for that health context. For the compounds themselves, see our Cannabis Cannabinoid Guide.
Official resources
- FDA: Cannabis quality considerations for clinical research
- CDC: Cannabis frequently asked questions
- California Department of Cannabis Control: Testing laboratories
For short definitions, return to the Cannabis Glossary.