How to Read a Certificate of Analysis

A Certificate of Analysis is a batch record, not a marketing document. The first thing to check is whether the lot number on the COA matches the lot you were shipped — a generic COA that is not tied to your lot has limited value.

Assay tells you how much active is present and by which method. Methods are not interchangeable: an HPLC assay and a titration can both be valid but will not always agree to the decimal.

Physical parameters — appearance, loss on drying, particle size, bulk density — are what your production line actually feels. They belong in your purchase specification, not just on the certificate.

Heavy metals and microbiological results should be read against the limits your destination market applies, which are not always the same as the supplier's default specification.

If a parameter you rely on is absent, ask for it before shipment rather than after. Third-party verification can be arranged pre-shipment when the value is critical to your release decision.