Begin with identity, not potency
The first task is proving that the report belongs to the product. Look for the product name or sample description, batch or lot number, laboratory identity, report date, and any sample identifiers. Formats vary among laboratories, but the batch connection is fundamental: a precise number from the wrong batch is not useful evidence about the package being examined.
Compare the batch number character by character. Then note when the sample was received, analyzed, and reported if those fields are provided. Dates establish the sequence of the record; they do not automatically tell you how the product was stored after testing. Keep the COA tied to its documented sample rather than treating it as a permanent profile for every item with the same name.
Read the cannabinoid panel row by row
The cannabinoid panel separates analytes such as THCa and THC because the acidic precursor and the converted molecule are not identical. Reports may express concentration as a percentage, milligrams per gram, or another clearly labeled unit. Before comparing numbers, confirm that the units match; a percentage and a milligram value should not be placed side by side as though they use the same scale.
Find THCa, then THC, then the reported Total THC. The check is Total THC = (THCa × 0.877) + THC. If a sample lists 60% THCa and 5% THC, the calculated total is 57.62%: 60 × 0.877 equals 52.62, plus 5. Small differences can come from displayed rounding, so calculate with the most precise values available on the report.
Treat the terpene panel as a profile
A terpene panel lists volatile aromatic compounds individually. Names such as caryophyllene, pinene, myrcene, limonene, and linalool are more informative together than as a single “total terpenes” figure because their proportions describe the measured composition. The panel is an analytical profile, not a flavor guarantee detached from storage and processing.
Terpenes can be lost through drying, curing, and storage, with losses reaching half of the total. That volatility makes the report date and batch match especially important. A terpene result documents the tested sample at a point in time; subsequent exposure to heat, light, or extended storage is outside the measurement printed on that page.
Separate potency from compliance testing
Potency occupies visual attention, but a compliance COA can contain much more. California’s Department of Cannabis Control lists required testing categories that include cannabinoids and terpenes, residual solvents and processing chemicals, residual pesticides, heavy metals, microbial impurities, mycotoxins, moisture content and water activity, and foreign material. The COA records a pass or fail for the substances covered by the applicable test.
Check each named section instead of assuming one overall potency result means every compliance category was analyzed. Also distinguish a numeric result, a reporting limit, and a pass/fail conclusion; they answer different questions. A blank field should not be interpreted as zero without the report’s legend explaining what the notation means.
Know what the document does not prove
A COA is evidence about the sample a licensed laboratory received, the methods it used, and the analytes it reported. It does not narrate how every package was handled after sampling, and it does not turn a limited panel into an unlimited screen for every possible compound. The scope is the set of tests actually shown.
Finish with three checks: correct batch, understandable units, and complete relevant sections. Recalculate Total THC when the component rows are available, read terpenes as a composition rather than a verdict, and retain the qualifiers printed by the laboratory. That sequence turns a dense report into a traceable record without asking it to answer questions it was not designed to test.
When two displayed values appear inconsistent, pause before calling the report wrong. First check whether one row uses a different unit, whether the total applies the 0.877 conversion factor, and whether the document rounds its visible numbers. If the mismatch remains after those checks, the report itself should control the interpretation rather than an assumption based on front-label shorthand. A transparent comparison records the exact rows used and preserves the laboratory’s notation.