Certificate of Analysis (COA)
Lab-issued document reporting cannabinoid potency and contaminant screening for a specific batch.
A COA is only as good as the lab that issued it and the batch it describes. It tells you what a lab measured in one specific batch on one specific day—not what the strain is always like, not how evenly dosed an edible really is, and not what wasn't tested for. Lab shopping and inconsistent results between labs are real problems; a high THC number alone isn't proof of quality.
Definition
A Certificate of Analysis (COA) is a document issued by an analytical laboratory that reports the measured chemical and biological contents of a specific batch of cannabis flower, concentrate, or infused product. In regulated markets, COAs are required before a product can be sold to consumers [1].
What a COA contains
A complete COA generally includes:
- Sample identifiers: batch/lot number, product name, sample weight, date received, date tested.
- Lab identifiers: lab name, license number, accreditation (ISO/IEC 17025 is the standard) [2], and the signature of an authorized analyst.
- Cannabinoid potency: at minimum THC, THCA, CBD, CBDA, often a full panel of 10–16 cannabinoids, reported as % w/w or mg/unit.
- Terpenes (sometimes optional): individual concentrations of mono- and sesquiterpenes.
- Contaminant panels: pesticides, heavy metals (lead, cadmium, arsenic, mercury), residual solvents (for extracts), microbials (yeast, mold, Aspergillus, E. coli, Salmonella), mycotoxins, and water activity [1][3].
- Pass/fail flags against the action limits set by the jurisdiction's regulator.
What a COA tells you
A COA documents what was measured in that specific batch at the time of testing Strong evidence[1]. It forms the basis for label claims like '24% THC' and confirms whether a product passed regulatory contaminant thresholds. Reputable COAs include a QR code or URL linking to the lab's verification portal, so you can confirm the document hasn't been altered or forged.
What a COA doesn't tell you
- It doesn't represent the strain or brand in general — only the batch tested. A second batch of the same product can differ substantially in cannabinoid content.
- It doesn't guarantee homogeneity. Cannabinoid content can vary within a single jar of flower; edibles can have uneven cannabinoid distribution despite a passing COA Strong evidence[4].
- It doesn't test for everything. A pesticide panel screening 60 compounds will miss the 61st if it's not on the list.
- Lab results can be inconsistent. Independent investigations have found systematic differences in potency reporting between laboratories testing the same samples, and some labs may report inflated THC values Strong evidence. A high THC number on a single COA should not be taken as definitive without independent verification.
How to verify a COA
Check that:
- The QR code or link on the product directs to a lab portal where you can view or verify the full report, not a generic image or marketing page.
- The batch number on the COA matches the batch or lot number on the product package.
- The lab name and license number are real and current in your jurisdiction's regulator database.
- The test dates are recent (typically within 6–12 months depending on the product type and jurisdiction).
Sources
- Government U.S. Food and Drug Administration. (2023). Regulation of Cannabis and Cannabis-Derived Products: Q&A. FDA.
- Government International Organization for Standardization. (2017). ISO/IEC 17025:2017 — General requirements for the competence of testing and calibration laboratories. ISO.
- Peer-reviewed Vandrey, R., Raber, J. C., Raber, M. E., Douglass, B., Miller, C., & Bonn-Miller, M. O. (2015). Cannabinoid Dose and Label Accuracy in Edible Medical Cannabis Products. JAMA, 313(24), 2491–2493.
- Peer-reviewed Valdes-Donoso, P., Sumner, D. A., & Goldstein, R. (2020). Costs of cannabis testing compliance: Assessing mandatory testing in the California cannabis market. PLOS ONE, 15(4), e0232041.
How this page was made
Generation history
Drafted with AI assistance and checked by a separate automated fact-check pass. Not every article has been read by a person. See how articles are made.
Related
- Slurry Test — A quick growing-medium test where you mix substrate with water to measure pH and EC of the...
- Water Activity — The ratio of available water in cannabis that determines mold risk and shelf stability.