How to read a certificate of analysis

A certificate of analysis records the result of testing performed on a specific batch of material. It is a record of a measurement, not a general property of the product, and reading it that way avoids most of the confusion around them.

The first thing to check is the batch or lot identifier, and whether it matches the material in front of you. A certificate for a different lot tells you about a different batch. This sounds obvious and is the single most common mismatch.

Next is what was actually measured and how. Purity, identity and content are different questions answered by different methods, and a document reporting one of them is silent on the others. A number without a stated method is not interpretable.

Then the date, and who performed the analysis — an in-house laboratory, the manufacturer, or an independent third party. Independent testing is not automatically better, but it is a different claim, and knowing which one you are looking at matters when the certificate goes into a compliance file.

Finally, treat the certificate as documentation for your own verification process rather than a replacement for it. What tests are required for your work, and whether a supplier's document is sufficient evidence for them, is a decision for your institution. If you need particular documentation for a product in this catalog, ask us before ordering and we will tell you plainly what is and is not available for it.