When can an examiner perform additional prior art searches for reexamination?

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.

An examiner can perform additional prior art searches for reexamination under specific circumstances. MPEP 2644 provides guidance on this:

“If the examiner believes that additional prior art patents and publications can be readily obtained by searching to supply any deficiencies in the prior art cited in the request, the examiner can perform such an additional search. Such a search should be limited to that area most likely to contain the deficiency of the prior art previously considered and should be made only where there is a reasonable likelihood that prior art can be found to supply any deficiency necessary to ‘a substantial new question of patentability’ or ‘a reasonable likelihood that the requester will prevail.’”

In essence, examiners can conduct targeted searches when they believe it’s necessary to supplement the existing prior art and there’s a reasonable chance of finding relevant art to support the determination.