International Searching Authority (ISA)

International Searching Authority (ISA) is a designated authority under the Patent Cooperation Treaty responsible for carrying out the international search for patent applications. Its role is to identify relevant prior art and provide an initial assessment of the invention’s patentability.

The ISA conducts a comprehensive search of available technical information and issues an International Search Report (ISR), along with a Written Opinion. These documents evaluate whether the invention appears to meet key criteria such as novelty, inventive step, and industrial applicability.

This early-stage assessment helps applicants understand the strengths and weaknesses of their application before entering national or regional phases. It also allows them to amend claims or adjust their patent strategy accordingly.

Major patent offices, including the European Patent Office, United States Patent and Trademark Office, and Japan Patent Office, act as ISAs under the PCT system.