Laboratory certificates are easy to produce and easy to borrow. A certificate from a previous lot, a different factory or a friendly lab looks exactly like a real one. The document itself is not the proof. How it was obtained is.
The five checks
- Accreditation: the laboratory should be accredited by a recognised body, in India that is NABL, and the certificate should carry the accreditation mark and the lab's report number.
- Who drew the sample: a certificate on a sample the factory sent itself tells you what the factory wanted tested. Insist on samples drawn and sealed by someone who works for you.
- Dates: the sampling date, the test date and the production date of the lot should line up. A certificate older than the lot is not for the lot.
- The spec on the certificate: the test parameters and limits should be the ones in your specification, not a generic set the lab runs by default.
- Delivery: ask the laboratory to send the certificate to you directly. If it only ever arrives through the supplier, you cannot know it was not edited.
Keep the counter-sample
Whoever draws the sample should keep a sealed duplicate. If a claim arises later, the counter-sample is what lets you prove what was shipped. Without it, a dispute is one word against another.