What is the “ready for patenting” test in the context of the on-sale bar?

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.

The “ready for patenting” test is part of a two-prong test established by the Supreme Court in Pfaff v. Wells Elecs., Inc. for determining whether an invention was “on sale” under pre-AIA 35 U.S.C. 102(b). The test states that an invention is “ready for patenting” if either:

• It has been reduced to practice before the critical date, or
• The inventor had prepared sufficiently specific drawings or descriptions of the invention to enable a person skilled in the art to practice the invention before the critical date.

As quoted from the MPEP: “Ready for patenting,” the second prong of the Pfaff test, “may be satisfied in at least two ways: by proof of reduction to practice before the critical date; or by proof that prior to the critical date the inventor had prepared drawings or other descriptions of the invention that were sufficiently specific to enable a person skilled in the art to practice the invention.” (MPEP 2133.03(c))