Key takeaways
- Tie the certificate to one batch or lot, with manufacturing and expiry or retest dates.
- For each parameter show the method, the specification limit and the actual result.
- Report results as measured, with units — never as "complies" alone.
- Include an explicit conformity statement and the authorised signatory with date.
- Keep the underlying laboratory records; the COA is a summary, not the evidence.
Required content
| Field | Purpose | Failure if missing |
|---|---|---|
| Manufacturer and site | Identifies who tested and where | Traceability broken |
| Product name, grade and code | Matches the datasheet specification | Cannot verify against spec |
| Batch / lot number | Ties results to physical goods | COA unusable at goods-in |
| Manufacturing and expiry / retest date | Shelf life control | Stock accepted past life |
| Quantity and packaging | Links to the shipment | Cannot reconcile with the invoice |
| Test parameters | Property, method, unit, specification limit, result | "Pass" with no data |
| Conformity statement | Declares the batch meets specification | Ambiguous acceptance |
| Sampling reference | How and when the sample was taken | Result not representative |
| Authorised signature and date | Makes the certificate accountable | Rejected by QA and customs |
Reporting results correctly
- Give the numeric result with units, plus the specification limit alongside it.
- Cite the test method by standard number and revision, or state the in-house method reference.
- Report below-detection results as "< limit of detection" with the limit stated, not as zero.
- Where a parameter is tested less frequently, mark it "skip lot" or "periodic" and give the last test date.
- Never round a result towards the specification limit; report as measured and let the conformity statement do its job.
An out-of-specification result must not be quietly retested until it passes. Investigate, record the investigation, and only report a retest where your quality system permits it and the reason is documented.
COA, certificate of conformity and datasheet
| Document | States | Batch-specific? |
|---|---|---|
| Certificate of analysis | Actual measured results for a batch | Yes |
| Certificate of conformity | That the goods conform to a specification or standard | Sometimes |
| Product data sheet | The specification and expected performance | No |
Buyers often ask for a COA when a certificate of conformity would do, and occasionally the reverse. Clarify at order stage which is required, because a conformity statement without test data will be rejected by a QA-driven receiving process.
Sending the COA with the shipment
For chemicals, food, pharmaceuticals and many industrial materials, the COA travels with the commercial invoice, packing list, product data sheet and safety data sheet. Match the batch numbers on the COA to the batch numbers on the labels and, where the packing list is batch-level, to the packing list too — mismatched batch numbers are the most common reason a consignment sits in a quarantine bay.
How to issue a certificate of analysis
Step 1: Identify the batch
Record product, grade, batch or lot number, quantity, and manufacturing and expiry dates.
Step 2: Pull the specification
Take the parameters and limits from the current product data sheet revision.
Step 3: Enter results and methods
For each parameter add the test method, unit, specification limit and measured result.
Step 4: Add sampling detail
State how and when the sample was taken and who tested it.
Step 5: State conformity
Declare whether the batch meets specification and note any agreed deviation.
Step 6: Sign and dispatch
Have an authorised signatory sign and date it, then send with the shipping documents.
Frequently asked questions
Who issues a certificate of analysis?
The manufacturer's quality function, or an accredited third-party laboratory. In either case an authorised signatory must sign and date it.
Is a COA the same as a certificate of conformity?
No. A COA reports actual test results for a specific batch; a certificate of conformity asserts that goods meet a specification without necessarily reporting the data.
Can one COA cover multiple batches?
Best practice is one certificate per batch, because results are batch-specific. Multi-batch certificates must list results separately for each lot.
How long should certificates of analysis be retained?
Keep them with the batch records for at least the product's shelf life plus the retention period required by your quality system or by regulation in the destination market.