Reading a certificate of analysis: what actually matters
Quality Assurance · 27 May 2026 · 5 min read
A COA is a release document, not a marketing sheet. Here is how to read one during vendor qualification, and which fields auditors check first.
A certificate of analysis records the results of tests performed on a specific batch against a defined specification. It is not a typical-values sheet and it is not transferable between batches. The first field an auditor checks is the batch number, followed by the manufacturing and retest dates.
The specification column matters more than the result column. A result of 'complies' against an undefined limit tells you nothing. Each test should state the method reference, the acceptance limit and the observed value, with numeric results reported to the precision the method supports.
Look for the analytical method reference against each test. A water content stated without reference to Karl Fischer titration, or an assay without the titration or chromatographic method, cannot be reproduced by your own laboratory during incoming inspection.
Finally, check the release signature and date. Batch release is a named responsibility. A certificate issued without an authorised signatory is an internal test report, not a release document.