What is the purpose of MPEP 2124?

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.

MPEP 2124 outlines an important exception to the general rule that a reference must qualify as prior art to be used in rejecting claims. The purpose of this section is to explain when and how a reference that is not prior art can still be used to show the state of the art at the time of the invention.

According to MPEP 2124: “In certain circumstances, references cited to show a universal fact need not be available as prior art before applicant’s filing date.” This exception allows examiners to use non-prior art references to demonstrate the level of ordinary skill in the art or to show the well-known nature of certain features.