ISO/IEC 17025:2017 is the international standard for the competence of testing laboratories. Accreditation is granted by an independent body and re-audited on a schedule. It is a measurement system with an audit trail behind it.
Traceable, repeatable, defensible
An accredited method comes with a documented procedure, calibrated equipment, trained operators, and stated measurement uncertainty. That is what lets a tensile or compression-set number stand up when a quality team asks how you know.
Scope is the part people miss
Accreditation applies to specific methods, not to a laboratory in general. Eighteen methods sit in our scope. We run others as well, and we identify those results as out of scope rather than letting the accreditation imply something it does not cover.
If you are relying on test data for a customer submission, ask any lab for its scope document and check that your method is on it. It is a reasonable question, and an accredited lab will have the answer ready.