What is the role of the United States Patent Classification (USPC) system in modern patent searches?

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Source: FAQ (MPEP-Based) BlueIron Update: 2024-09-27 4 Rules 5 Related FAQs 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 United States Patent Classification (USPC) system, while no longer the primary classification system, still plays a role in modern patent searches: Serves as a secondary classification system Remains available for searching older U.S. patent documents Complements the CPC system for comprehensive searches According to MPEP 902 , “The United States Patent Classification System (USPC) is also available for searching.” While the CPC has become the primary system, the USPC remains valuable for searching historical patent documents and ensuring thorough prior art searches across multiple classification systems. Related Rules from the Manual of Patent Examining Procedure 4 rules Collapse Classification Orders Affect Existing Definitions MPEP 902.02 Recommended Examiner Definitions Must Be Updated Periodically MPEP 902.02 Recommended Classification Orders Available Online for USPTO Personnel MPEP 902.02 Classification Home Page Must Be Accessible via Toolkit MPEP 902.02 Other Related FAQs 5 FAQs Collapse How can patent examiners access the Classification Home Page? How can I access the Cooperative Patent Classification (CPC) system? What automated search tools are available to patent examiners? How does the Cooperative Patent Classification (CPC) system work? What is the purpose of the Cooperative Patent Classification (CPC) system?