Match the COA to your package
A COA describes one batch, not a strain and not a brand. Before reading any numbers, make sure the report belongs to the product in your hand. Compare these details with the label:
- Batch or lot number. It should match the label exactly. A report for a different batch tells you nothing about yours.
- Product name and type. Flower, pre-rolls and extracts are tested separately, so a flower report should say flower.
- Lab name and credentials. The report should name the testing lab, with contact details and, ideally, its license or accreditation number.
- Dates. Look for when the sample was collected and when it was tested. The test should come from the same harvest as your package.
Cannabinoids: THCA, delta-9 THC and total THC
The cannabinoid table lists each compound the lab measured, usually as a percentage of weight, in milligrams per gram, or both. In raw flower, most of the THC shows up as THCA, the acid form the plant makes. Delta-9 THC is usually a much smaller figure.
Because the two forms are related, many reports add a total THC line. A common convention calculates it as delta-9 THC plus THCA multiplied by 0.877. The 0.877 factor accounts for the mass THCA loses when it converts to delta-9 THC. Total CBD is often worked out the same way from CBD and CBDA. Exact methods can differ between labs and markets, so check the notes on the report.
You may also see minor cannabinoids such as CBG or CBN. A result of ND means the lab did not detect that compound.
Terpenes: the aroma compounds
Terpenes are aromatic compounds the plant produces. They shape how flower smells and tastes, which is why two batches with similar cannabinoid numbers can be very different on the nose. Common names on a terpene panel include myrcene (earthy and musky), limonene (citrus), beta-caryophyllene (peppery), alpha-pinene (pine) and linalool (floral).
Results are usually listed per compound, with a total terpene figure at the bottom. Not every COA includes a terpene panel, so its absence is not a problem in itself. The profile can also shift from one harvest to the next.
Contaminant panels: what pass and fail mean
This is the safety half of the report. Each panel compares what the lab found against a limit, and marks the result pass or fail. Depending on the product and the market, you may see:
- Pesticides. A long list of specific compounds, each with its own limit.
- Heavy metals. Usually arsenic, cadmium, lead and mercury.
- Microbials. Total yeast and mold counts, and screens for specific bacteria.
- Mycotoxins. Toxins some molds produce, such as aflatoxins and ochratoxin A.
- Residual solvents. Mostly relevant to extracts rather than flower.
- Moisture content or water activity. A measure of how dry the flower is, which bears on how well it keeps.
A pass means the result came in under the limit. A fail means it went over. Which panels are required, and where each limit sits, vary from one market to another, which is why most reports print the limit beside every result.
Red flags to watch for
- The batch or lot number on the report does not match your label.
- No lab name, address or license or accreditation details.
- A test date that is far older than the package date, or from a different harvest.
- Panels marked as not tested with no explanation.
- A cropped screenshot or edited file that you cannot trace back to the lab.
If anything looks off, ask the dispensary for the full report for your batch.