What is a “threshold issue” in patent interference proceedings?

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 threshold issue in patent interference proceedings is a critical concept defined in 37 CFR 41.201. The MPEP states:

“Threshold issue means an issue that, if resolved in favor of the movant, would deprive the opponent of standing in the interference.”

One important threshold issue specifically mentioned is:

“Unpatentability for lack of written description under 35 U.S.C. 112 of an involved application claim where the applicant suggested, or could have suggested, an interference under § 41.202(a).”

This highlights the critical nature of the written description requirement in interference proceedings, as inadequate written description can potentially disqualify a party from the interference entirely.