Guide ยท Documents
Certificate of analysis vs certificate of conformance
- Short answer
- A certificate of analysis (CoA) reports the tests run on one lot, the result of each and the specification it is measured against. A certificate of conformance (CoC) states that a product or shipment meets stated requirements, usually without results. A CoA gives you numbers to check. A CoC gives you a claim to accept or to query.
General background, not regulatory or GMP advice. What you must hold for a material is set by your specification, your supplier agreement and the rules that apply to you.
Same family, different promises
Suppliers use several names. Certificate of conformity, certificate of compliance and declaration of conformity usually mean a conformance statement. Certificate of quality is used for either. Read the content, not the title: a results table makes it a CoA, and a signed sentence without one makes it a CoC.
Both are the supplier's own statements. A CoA usually comes from the manufacturer's quality control laboratory or from a testing laboratory. A CoC is usually signed by a quality or management representative, and may refer to a purchase order, a specification revision or a standard instead of to a lot. Some documents combine the two: a results table plus a closing sentence that the lot conforms.
Telling the two apart, and deciding what to ask for
Six checks, in the order that settles it fastest.
Look for a results table
A CoA lists each test with its specification and the result for the lot. If there is only a statement such as 'product conforms to specification', you are holding a CoC or a data sheet, whatever the title says.
Check what is identified
A CoA names one lot and its dates. A CoC may name an order, a product family or a period. A certificate that cannot be tied to the lot in front of you attests nothing about it. See batch and lot numbers.
Read exactly what is attested
Note the wording and the reference: 'conforms to specification X revision Y', 'meets the purchase order', 'complies with a named standard'. Each is a different promise, and an unnamed specification cannot be checked.
Note who signs
Record the name, role and date as printed, and whether the document says it is valid without a signature. A laboratory or QC signatory suggests a CoA; a quality or management signatory suggests a CoC.
Match the document to your requirement
If your specification asks for reported values, such as an assay or a heavy-metal result, a CoC cannot supply them. Ask for the CoA, or record the gap and follow your procedure.
File both under the lot
Keep the CoA, any CoC and the delivery documents together, so a reviewer sees what was claimed and what was measured. See the incoming-material review checklist.
CoA and CoC side by side
Typical differences. Suppliers vary, so check the document you actually hold.
| Question | Certificate of analysis | Certificate of conformance |
|---|---|---|
| What it states | Tests performed, results and the specification, for one lot | The product or shipment meets stated requirements |
| Numbers to verify | Yes: a result for each test | Usually none |
| Tied to a lot | Normally: batch or lot number and dates | Sometimes: may name only an order or a product |
| Typically signed by | Laboratory or QC unit | Quality or management representative |
| What you can check | Each result against its limit, units and methods | That the wording, reference and signature are present |
| What it cannot show | Tests the supplier left out | Whether any test was run at all |
| Typical use | Receiving review; one input to the release decision | Supporting statement; sometimes the only paper for goods not tested lot by lot |
What goes wrong when one stands in for the other
- A CoC accepted where the specification needs results. Nothing in it can be compared with a limit, so the review has no data to work with.
- A 'CoA' that is really a CoC. Complies or Conforms printed against numeric limits is a statement, not a result. There is no value to verify.
- A typical-values sheet titled as a certificate. No lot number, no dates and averages instead of results do not describe the lot you received.
- A blanket sentence under a results table. 'Product conforms to specification' can sit under a table with a result outside its limit. Read the rows, not the closing line.
- An unnamed reference. 'Meets specification' with no specification number or revision cannot be checked against anything.
How CertiClean helps
CertiClean reads the results table of a CoA into one row per test and compares each result with the limit printed beside it. It cannot do that for a conformance certificate: with no table there is nothing to read, and the page says so. Where a CoA prints Complies against a numeric limit, the row is marked could not evaluate, because a statement is not a measured value. See CoA to Excel and pricing.
Free allowance: 1 file per day, up to 10 pages, no account.
Questions people ask
Is a certificate of conformance the same as a certificate of compliance?
In practice the terms are used interchangeably, along with certificate of conformity. What matters is what the document attests, to what reference and for which lot. Read the wording rather than relying on the title.
Can a certificate of conformance replace a CoA?
Only if your specification and quality system allow it for that material. If you need reported values, such as an assay or an impurity result, a conformance statement cannot provide them.
Does a CoA also state conformance?
Often it ends with a statement that the lot meets the specification. That statement is the supplier's conclusion. The numbers above it are what you can check, so compare them with the limits yourself.
Who issues a CoA, and who signs a CoC?
A CoA typically comes from the manufacturer's quality control laboratory or an independent laboratory. A CoC is typically signed by a quality or management representative. Practice varies, so record what the document itself says.
Does a CoC need a lot number?
If you want to tie it to the delivery, yes. Some CoCs refer only to an order or a product, which says nothing about the lot in front of you. Whether that is acceptable is for your procedures to decide.
Why would a supplier send a CoC instead of a CoA?
Common reasons are goods not tested lot by lot, items made to a standard rather than a specification, or a default document. If you need results, ask for the CoA and keep the request on record.
Is a certificate of origin the same thing?
No. A certificate of origin states where goods were made, usually for customs. It says nothing about test results or whether a product meets a specification.
What should I record when only a CoC arrives?
Note the document type, lot, date and signer, and that no results were supplied. Then follow your procedure, which often means requesting the CoA and keeping the material on hold until the question is settled.