How to Read a Certificate of Analysis

Start with identity

A certificate of analysis, often called a COA, is a document associated with a particular material or sample. Before drawing conclusions, look for the basic identifiers: the item name, lot or batch reference where applicable, document date, and the laboratory or issuer named on the record.

A document is most useful when its identifiers can be connected clearly to the thing it describes. If that connection is unclear, the document should be treated as incomplete context rather than proof.

Read the method with the result

Numbers on a COA only have meaning alongside the method, units, and acceptance criteria that produced them. A result without a stated method or specification cannot answer every question a reader may have.

Readers should also distinguish identity, composition, and impurity-related testing. These are different questions, and one result is not a substitute for another.

What a COA cannot do

A COA does not replace independent investigation, source documentation, or an understanding of what was—and was not—tested. It should be a starting point for traceability, not a marketing ornament.