June 2026
How to read a Certificate of Analysis (COA)
A COA is the document that backs an identity and purity claim. Here's how to read one and confirm it against the batch you received.
What a COA is
A Certificate of Analysis (COA) is a lab-issued document that records the analytical results for a specific batch of material. It is the evidence behind any identity or purity statement — without it, a claim is just a claim.
A COA is batch-specific. A certificate for one lot does not describe a different lot, which is why the batch/lot number on the vial should match the batch/lot number on the certificate.
The fields to check
Product and batch/lot: confirm both match the label on the vial you received.
Test method: identity and purity are typically reported by HPLC, sometimes alongside mass spectrometry (MS) for identity confirmation.
Result vs. specification: the certificate states a measured result and the specification it is checked against (for example, an identity-purity threshold).
Date and issuing laboratory: a COA should name the lab that performed the analysis and when.
Verifying it yourself
Where a product is independently tested, the certificate is published in full so you can open it, read the method and result, and match the batch. Where a product has not been tested, we say so rather than imply a certificate exists.
If anything on the certificate does not match the vial, contact support before using the material.
Educational content for qualified researchers. All products referenced are for laboratory and research use only — not for human or veterinary consumption, and not intended to diagnose, treat, cure, or prevent any disease.