Can I use MPE instead of uncertainty for acceptance decisions?

ISO/IEC 17025:2017 (7.8.6) requires that when you state conformity, the decision rule must be documented, agreed, and account for measurement uncertainty. 'Indication within MPE, uncertainty ignored' IS a decision rule — simple acceptance per ASME B89.7.3.1 / ILAC-G8 — but it must be declared, and it carries up to ~50 % false-accept risk at the limit.

Common defensible choices:

• Simple acceptance with a TUR floor (e.g. Z540.3 style: risk contained because uncertainty is small vs tolerance);
• Guard-banded acceptance: acceptance limit = tolerance − U (ILAC-G8 'binary statement, guarded acceptance'), pushing false-accept risk to ~2.5 % at the limit;
• JCGM 106 risk calculation where the stakes justify it.

For your suppliers: require the certificate to state the decision rule applied. 'Pass' with no rule and no uncertainty is not evidence of conformity you can lean on in an audit.