How to read a certificate of analysis (COA)
The fields that matter, how to match a document with your batch, and the warning signs of an unreliable certificate.
What a COA is
A certificate of analysis is the report of the laboratory that tested one production batch. It applies to that batch only: a certificate for another batch number says nothing about yours.
The fields to check
Product name and batch (lot) number. Name of the laboratory and date of the analysis. Method used, for example HPLC for purity and mass spectrometry (MS) for identity. Results with their units, such as purity in % and the measured molecular mass compared with the theoretical one.
Match it with your vial
The batch number printed on the label must be the same as the one on the certificate. On this site, every document is listed under its batch number on the product page and on the COA page.
Warning signs
No laboratory name or date, no batch number, results without a method, values that are “too perfect” on every batch, or a file that looks edited. When in doubt, ask for the original report.