What is a substantial new question of patentability (SNQ) in patent reexamination?

This page is an FAQ based on guidance from the Manual of Patent Examining Procedure. It is provided as guidance, with links to the ground truth sources. This is information only: it is not legal advice.

A substantial new question of patentability (SNQ) is a crucial concept in patent reexamination. According to MPEP 2242:

“If the prior art patents and/or printed publications raise a substantial new question of patentability as to at least one claim of the patent, then a substantial new question of patentability as to the patent is present, unless the same question of patentability has already been: (A) decided in a final holding of invalidity by a federal court in a decision on the merits involving the claim; (B) decided in an earlier concluded examination or review of the patent by the Office; or (C) raised to or by the Office in a pending reexamination or supplemental examination of the patent.”

In essence, an SNQ is a new, non-cumulative technological teaching that was not previously considered and discussed during the original examination, and that is relevant to determining the patentability of at least one claim.