Read a cannabis COA the way an assessor does.

The 12 notes

1. 1Lab, license and accreditation

   What it is

   Who ran the tests, the state license that lets them report compliance results, and the ISO/IEC 17025 accreditation that says an assessor has checked their methods.

   What to check

   Look the certificate up in the accreditation body’s public directory and open the scope. Accreditation covers the tests and matrices listed there, not the whole lab.

   Common mistake

   Treating the accreditation line as blanket cover. A test outside the scope is not an accredited result, even from an accredited lab.

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2. 2Client, batch and sample

   What it is

   Whose product it is, the batch the sample came from, and the ID that ties this report to its chain of custody.

   What to check

   The batch number matches the package label and the track-and-trace record. Batch size and sample weight are printed.

   Common mistake

   Reusing one certificate for a later harvest or a repackaged lot. A COA covers the batch that was sampled, nothing else.

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3. 3Matrix

   What it is

   What the sample is: dried flower, here. The matrix decides which panels run and which limits apply.

   What to check

   The matrix matches the product, and the lab’s method is validated for that matrix (ISO 17025 clause 7.2.2).

   Common mistake

   Reading results against the wrong limits. In California, arsenic is capped at 0.2 µg/g for inhalable products and 1.5 µg/g for the rest.

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4. 4Sample history

   What it is

   When the sample was collected, received, tested and reported.

   What to check

   The lab received the sample promptly and tested it inside its hold times. For potency, check the report is recent.

   Common mistake

   Trusting an old potency number. In storage, THCA slowly converts to Δ9‑THC and THC oxidizes to CBN, so a months-old COA can drift from what is in the jar.

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5. 5Summary and overall result

   What it is

   One line per panel, and a pass or fail for the batch.

   What to check

   Every panel your state requires for this product appears, with a result. The overall pass covers only the panels that ran.

   Common mistake

   Reading NT as a pass. NT means not tested: a panel that never ran cannot fail.

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6. 6Potency: ND, <LOQ and the basis

   What it is

   Each cannabinoid as a percentage and in mg/g (1% is 10 mg/g). ND means not detected. <LOQ means the compound was seen, but below the level where the method can put a reliable number on it.

   What to check

   An LOQ for every analyte, and the basis printed: dry weight or as received.

   Common mistake

   Reading ND as zero, or <LOQ as absent. Both say only that the amount is below what this method can measure.

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7. 7Total THC and total CBD

   What it is

   Heat converts THCA to Δ9‑THC by stripping off CO₂, and what remains is 87.7% of the mass. So total THC = Δ9‑THC + 0.877 × THCA. Here: 1.80 + 0.877 × 23.47 = 22.38%.

   What to check

   The formula is printed, and the report says how results below LOQ enter a total. This one counts them as zero.

   Common mistake

   Adding THCA and Δ9‑THC straight (25.27% here), which overstates total THC by about 13%.

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8. 8Moisture and water activity

   What it is

   Moisture is the share of the weight that is water. Water activity is how much of that water microbes can use; Colorado and California both cap dried flower at 0.65 aw.

   What to check

   The basis. This report is on dry weight: dry = as received ÷ (1 − moisture % ÷ 100). At 11.2% moisture, 22.38% total THC dry is 19.87% as received.

   Common mistake

   Comparing a dry-weight COA with an as-received one. Water alone moves total THC by 2.51 points here.

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9. 9Pesticides and residual solvents

   What it is

   Screens against a state list. California lists 66 pesticides: some fail on any detection, the rest have action levels.

   What to check

   Each LOQ sits well below its action level, or a pass proves little. Which products need a solvent panel depends on the state: Colorado requires it for solvent-based concentrates, not flower. This sample ran it anyway.

   Common mistake

   Assuming every state screens the same compounds. A pass under one state’s list says nothing about compounds only another state lists.

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10. 10Heavy metals

    What it is

    Arsenic, cadmium, mercury and lead, measured by ICP-MS in µg/g (ppm).

    What to check

    Which limits were applied. The ones shown are Colorado’s and California’s for inhalable products. Washington’s arsenic limit is 2.0 µg/g, ten times higher.

    Common mistake

    Judging a result against another state’s limits. The same number can pass in one state and fail in the next.

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11. 11Microbials and mycotoxins

    What it is

    Pathogens reported as detected or not detected in a stated mass, total yeast and mold as a count in CFU/g, and aflatoxins and ochratoxin A in µg/kg.

    What to check

    The mass behind “not detected” (1 g here), and the units: mycotoxins are in µg/kg (ppb), metals in µg/g (ppm), a factor of 1,000 apart.

    Common mistake

    Assuming every state tests the same organisms. Colorado caps total yeast and mold at 10,000 CFU/g; California sets no yeast and mold limit at all.

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12. 12Methods, QC and sign-off

    What it is

    The instrument and procedure behind each panel, a statement that the batch’s QC samples passed, and the reviewer’s signature.

    What to check

    Each panel names its method, with LOD and LOQ; the report is signed and dated; an amended report says what changed and why.

    Common mistake

    Acting on a preliminary or unsigned result. ISO 17025 (clause 7.8) requires results to be reviewed and authorized before release.

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