A certificate of analysis is evidence about one sample. Whether it is evidence about your consignment depends entirely on what it says, and a certificate that lists only parameters and the word pass is not evidence of anything useful.
The checks, in order
- Identity. Does the lot or batch code on the certificate match the code on the pallet and on the invoice? A mismatch is the single most common defect.
- Sample origin. Who drew the sample, when, and under which sampling plan? A sample supplied by the producer is a different evidential proposition from one drawn under supervision.
- Dates. Date of sampling, date of receipt at the laboratory and date of analysis. A long gap matters for microbiological and for oxidation parameters.
- Method. Named by standard reference and edition, not merely as chromatography. The method has to be one that applies to your matrix.
- Accreditation. Is the specific method and matrix inside the laboratory’s accredited scope, or is the test marked as outside scope?
- Units and basis. Milligrams per kilogram against grams per hundred grams, and wet basis against dry basis, account for most false failures.
- Limit of quantification. A not-detected result is only meaningful next to the reporting limit; a limit above the legal maximum tells you nothing.
- Uncertainty and conformity. If the certificate states conformity against a limit, it should state the decision rule used and how expanded uncertainty was applied.
File the certificate against the lot, not against the supplier, and keep the retained sample so a disputed result can be re-tested rather than argued. How to write the dispute clause in advance is covered in the laboratory routing comparison.
Vorezan is an information platform and does not verify or issue certificates.