Is it acceptable to use ‘optionally’ in patent claims?

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.

Yes, using the term ‘optionally’ in patent claims can be acceptable, but it requires careful consideration. The MPEP 2173.05(h) provides guidance on this:

“In Ex parte Cordova, 10 USPQ2d 1949 (Bd. Pat. App. & Inter. 1989) the language ‘containing A, B, and optionally C’ was considered acceptable alternative language because there was no ambiguity as to which alternatives are covered by the claim.”

However, the MPEP also warns:

“In the instance where the list of potential alternatives can vary and ambiguity arises, then it is proper to make a rejection under 35 U.S.C. 112(b) and explain why there is confusion.”

Therefore, while ‘optionally’ can be used, it’s crucial to ensure that it doesn’t introduce ambiguity into the claim.