What is a constructive reduction-to-practice in patent law?

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 constructive reduction-to-practice in patent law refers to a description in a patent application that would have anticipated the subject matter of a count in an interference proceeding. According to MPEP 2304.02(c), “A description in an application that would have anticipated the subject matter of a count is called a constructive reduction-to-practice of the count. One disclosed embodiment is enough to have anticipated the subject matter of the count.”

It’s important to note that if an application is relying on a chain of benefit disclosures, the anticipating disclosure must be continuously disclosed through the entire benefit chain, or no benefit may be accorded.