How to Read a COA: 12 Things That Actually Matter

A Certificate of Analysis is the single most important document in a botanical transaction: it is the supplier's signed statement of what is in the lot. Treat it as evidence to be cross-examined, not a receipt to be filed. Work through these twelve in order.

The checklist

1. 1Lot / batch number — present, unique, and matching the drum label and the invoice. If the COA lot does not match the physical lot, nothing else on the page applies to what you received.
2. 2Botanical identity — Latin binomial and plant part stated explicitly. “Ginseng” is not an identity; “Panax ginseng, root” is.
3. 3Active / assay result — the standardised marker, its value, and the method (HPLC / HPTLC / UV). Confirm it is a result, not a restatement of the spec target.
4. 4Specification range — every result printed next to its acceptance limit, with a clear pass/fail. A number with no limit beside it cannot be judged.
5. 5Test method references — named methods (USP, EP, AOAC, in-house validated) rather than blank cells. “Conforms” with no method is a hope, not a result.
6. 6Heavy metals — lead, arsenic, cadmium, mercury, each with a numeric result and limit appropriate to your destination market, not just “within limits”.
7. 7Pesticide residues — screened to the relevant panel (e.g. EU MRLs) for botanicals, especially for organic or EU-bound material.
8. 8Microbiology — total plate count, yeast & mould, and pathogens (E. coli, Salmonella, S. aureus) with counts and limits, not a bare “absent”.
9. 9Residual solvents — for solvent-extracted material, the solvent named and quantified against ICH Q3C class limits.
10. 10Physical / organoleptic — appearance, colour, odour, particle size / mesh, loss on drying, bulk density: the parameters that govern how the powder behaves on your line.
11. 11Manufacturing & expiry / retest dates — present and sensible; a COA with no date context tells you nothing about remaining shelf life.
12. 12Authorised signatory & QC release — signed and dated by a named QC authority, ideally referencing the testing lab (and its NABL/ISO 17025 status).

Beyond the twelve

Three habits raise your confidence further. First, periodically verify a COA against an independent third-party test on a retained sample — a supplier whose COAs reconcile with outside labs has earned trust. Second, watch consistency across lots: a marker that lands on exactly the same value every single lot can indicate a copied template rather than a fresh assay. Third, confirm the testing laboratory's accreditation scope actually covers the test in question — NABL or ISO 17025 accreditation is method-specific, not a blanket badge.