A certificate of analysis (COA) is a document that states the test results for one specific lot, usually set against the agreed specification. It travels with the shipment and tells your customer, and sometimes your authority, what the goods contain.
A COA can be issued by the supplier's own quality control lab or by an independent lab. Both are common. They do not carry the same weight.
Supplier COA versus lab report
In practice, the term COA is used loosely. Some buyers mean the supplier's own document. Others mean any test report that comes with the goods. Agree in your contract which one you need, and from whom.
- Supplier COA: issued on the supplier's letterhead, often from its in-house lab. It usually covers physical and simple chemical tests, and sometimes copies results from an outside lab.
- Independent lab report: issued by an accredited lab on its own letterhead, for the sample it received.
- Combined approach: the supplier's COA lists the routine results and attaches the independent lab report for residues, mycotoxins and microbiology.
What a COA should contain
- Product name, grade and form.
- Lot or batch number, matching the bags and packing list.
- Production and expiry or best-before dates.
- Quantity and number of packages in the lot.
- Each parameter, its specification limit, the result and the unit.
- The test method for each parameter, or a reference to it.
- Who tested it, and a reference to any outside lab report.
- Name and signature of the person responsible, and the date.
Limits of a supplier COA
A supplier COA is a statement by the seller about its own goods. It is useful, and many importers require one, but it is not independent. Some suppliers issue the same COA for every lot, or copy results from an earlier test. In-house labs rarely have the equipment for pesticide, ETO or mycotoxin work.
For the tests that decide whether a lot can enter your market, rely on an accredited lab report from a sample drawn by you or your agent. See how to know a lab report is genuine and not borrowed.
Making the COA useful
Attach a COA template to your specification so the supplier reports the same parameters, units and methods each time. Ask for the COA before loading, check it against your independent results, and keep it with the shipping documents. Store COAs by lot number, so you can find them quickly if a customer or authority asks. For product-specific COA content, see examples such as tests on an edible oil certificate of analysis.
How we help
We agree a COA format with your supplier, then check each lot's COA against our own sealed-sample results from an NABL-accredited lab. Any mismatch is raised before the container is loaded. Ask for a free sourcing review.