Glossary
Out of specification (OOS)
A test result that falls outside the acceptance criteria of the specification it was tested against. An OOS result triggers a documented laboratory investigation before any decision about the batch is made.
Why it matters on a certificate
On a certificate, a result outside the printed limit should never appear silently: a batch released with an uninvestigated OOS result is a serious signal about the issuer's quality system. Reviews also catch the subtler case: a result inside the printed limit but outside the limit of the standard the certificate claims. The first is a failed test; the second is a failed claim.
A worked example
A certificate prints an illustrative water-content limit of "not more than 0.5%" and reports 0.7% for that test, with the batch nonetheless marked released. The document contradicts itself, and the review surfaces it as a hold point rather than averaging it away.
Examples are synthetic and illustrative; any limits shown are not the requirements for any particular material.
The COA Validator checks the element this term describes on every certificate it reads, and reports what is present, what is missing and what does not add up.