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Certificate of analysis: reading one instead of filing it

A certificate of analysis states what was tested and what was found. What has to be on it, the checks that take a minute, and why filing it unread is the risk.

How-toC

A certificate of analysis is the supplier’s statement of what they tested on a specific batch and what the results were. It arrives with the delivery, it is usually filed within seconds of being received, and it is often the only technical evidence you hold about material that goes into your product. The two-minute read at goods-in is what separates a document that protects you from one that merely exists.

What a certificate of analysis has to show

  • The batch or lot number, matching the material physically in front of you rather than the order.
  • The product identity and grade exactly as you specified it, not a near neighbour.
  • Each test performed, the method used, the specification limit and the actual result — a result with no limit beside it is not verifiable.
  • The date of manufacture and, where it applies, the retest or expiry date.
  • Who authorised the release, by name or role.
  • Whether the results are from testing this batch or carried over from a previous one, which is a real and legitimate practice that must be disclosed.

The checks that take a minute

  1. Does the batch number on the certificate match the batch number on the container? This single check catches more errors than every other combined.
  2. Are all your specified parameters present, or only the supplier’s standard set? A missing parameter is the most common quiet substitution.
  3. Does every result sit inside the limit — and where a result is exactly at the limit, is that plausible or suspiciously convenient?
  4. Is the method stated, and is it the method you agreed? The same parameter measured two ways can give two different answers.
  5. Is the certificate for the material you actually received, or a generic type certificate for the product line?

A certificate of analysis is a supplier’s claim, not an independent verification. Where the material is critical, periodic identity or full testing on receipt is what turns the claim into evidence — and the frequency of that testing should be a written decision based on risk and supplier history, not on how busy the lab is that week.

Keeping them so they can be found

  • One certificate per received batch, linked to the goods received note rather than filed by supplier and date.
  • Traceable forward: which of your batches used which incoming lot, so a supplier recall becomes a query rather than a week of paper.
  • Retained at least as long as the product it went into plus its shelf life, which is usually longer than your purchasing records are kept.
  • Deviations from specification recorded as a decision — accepted under concession, rejected, or returned — never as an unremarked file.
  • Where the batch record depends on these values, take them from the certificate once rather than retyping them in two places.

Where the certificates live

Ettex Records holds each certificate against the batch it describes, with the supplier, the lot, the receipt date and the acceptance decision as fields, so a recall notice from a supplier turns into a filter rather than an archaeology exercise. It sits next to the goods received note and the batch record, which is where the forward and backward traceability actually joins up. Ettex does not test materials, does not verify supplier claims and does not issue certificates — it keeps the ones you receive findable and tied to what you did with the material.

Frequently asked

Is a certificate of analysis the same as a certificate of conformance?

No. A certificate of conformance states that the material meets specification; a certificate of analysis gives the actual measured results. The second is much more useful, and where a supplier offers only the first for critical material, that is worth negotiating.

What if the supplier will not provide one?

For anything that affects product quality or safety, treat that as a qualification failure rather than an inconvenience. It should have been settled during supplier onboarding, and raising it after the first delivery is a much weaker position.

Do we have to keep paper copies?

Almost never — most regimes accept electronic records provided they are complete, attributable and cannot be altered without trace. What matters is that the copy you keep is the one you received and that you can show when it arrived.

SL
Written by Sofia L.

Part of the Ettex team — writing about product, engineering and the future of work.

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