MPEP § 902 — MPEP § 902
Current through: 2022-07-01

902-Search Tools and Classification Information 
 
 

 
 
 
 
 
 
 
 

 

 
 
 

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 

 
 
 
 
 

 
 
 
 
 
 
 
 
 
 
 

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 Chapter 0900 

 Section 902 
 

 
 
 
 
 
 902 Search Tools and Classification Information [R-07.2022]

 There are multiple classification systems used throughout the
 international patent system. These include the Cooperative Patent Classification System
 (CPC), U.S. Patent Classification System (USPC), the International Patent Classification
 System (IPC), and the Locarno International Classification (Locarno). As of January 1,
 2013, the USPTO moved from using the USPC system to the CPC system for classification of
 pending utility applications. All U.S. utility patents and U.S. utility Patent Application
 Publications published after December 31, 2014 no longer receive classifications within the
 USPC. The USPC is now a static searchable database for all utility areas. Only U.S. design
 and plant patents and U.S. plant patent application publications continue to receive
 classification within the USPC.
 

 
 902.01 Classification Manual for the U.S. Patent Classification
 System [R-07.2022]
 

 The U.S. Patent Classification System is a static system
 and is no longer updated for the utility classes. The USPC remains active for the plant
 and design classes.
 

 The United States Patent Office (the Office) maintains an electronic
 classification manual for the U.S. Patent Classification System (USPC). The complete
 manual is available to USPTO personnel from the Classification Home Page ( https://ptoweb.uspto.gov/patents/classification-resources/ ), which
 is accessible from the desktop via the Patent Examiner’s Toolkit. The Manual of
 Classification is also available via the Internet at www.uspto.gov/SearchClassification , however The Manual of
 Classification will no longer be updated after December 31, 2014. See
 MPEP §
 905 et seq. for information regarding the Cooperative Patent
 Classification System. 
 

 Each class has a title descriptive of its subject matter, is identified
 by a class number, and is subdivided into a number of subclasses. Each subclass also has
 a descriptive title, is identified by a subclass number, and the subclass number is an
 integral number that may contain a decimal portion and/or alpha characters. A complete
 identification of a subclass requires both the class and subclass number and any alpha
 or decimal designations; e.g., 417/161.1A identifies Class 417, Subclass 161.1A.
 

 The Manual of Classification for the USPC system contains ordered
 arrangements of all class and subclass titles, the ordered arrangements are referred to
 as class schedules. The class and subclass titles are brief and are as suggestive as
 possible of the subject matter included. Therefore, it is best not to depend exclusively
 upon titles to explain the subject matter encompassed by a class and subclass but to
 refer also to the respective definitions and notes. If a search is to be expeditious,
 accurate, and complete, the Manual of Classification should be used only as a key to the
 class or subclass definition and appended notes.
 

 The Manual of Classification for the USPC system has the following
 parts:
 

 
 (A) Overview of the U.S. Patent Classification System. 

 (B) Classes Within the U.S. Classification System Arranged by Related Subject
 Matter: A hierarchical arrangement of class titles organized into
 four main groups by related subject matter. Only as a last resort should this
 hierarchical arrangement of class titles, be used to determine document placement,
 i.e., when none of the other classification criteria, such as comprehensiveness,
 etc., allow placement. This part also includes an exact hierarchical listing of
 the synthetic resin and chemical compound classes.
 

 (C) Classes Arranged by Art Unit (CAAU): A list, in numerical
 order, by art unit indicating the classification(s) assigned to each.
 

 (D) Classes Arranged Numerically With Art Unit and Search Room Locations
 (CAN): A list of classifications in numerical order by class number
 giving the class title, the art unit to which the art is assigned, and the
 examiner search room in which the art can be found.
 

 (E) Classes Arranged in Alphabetical Order (CAA): A list of classes
 in alphabetical order by class title with associated class numbers.
 

 (F) Class Schedules: Class schedules for utility patent, design,
 and plant classes.
 

 
 
 902.01(a) Index to the U.S. Patent Classification System [R-08.2012]

 The Index to the U.S. Patent Classification System (USPC) is an
 alphabetic listing of technical and common terms referring to specific classes and
 subclasses of the USPC. The index is used as an initial entry into the system and
 should not be considered exhaustive. All appropriate class schedules should be
 scanned for specifically related subclasses, and the definitions and associated notes
 of the pertinent classifications should also be reviewed, even when the citation
 found in the Index appears to be restricted to a specific subject matter area.
 

 The Index is regularly updated. Suggestions or changes to the Index
 are encouraged and should be directed to the Technology Center (TC) classification
 contact in the TCs. 
 

 The Index is available online to USPTO personnel from the
 Classification Home Page – USPC Index. The Classification Home Page ( http://ptoweb:8081/ ) is accessible from
 the desktop via the Patent Examiner’s Toolkit.
 

 

 

 
 902.02 Class and Subclass Definitions in USPC [R-01.2024]

 All of the classes within USPC have definitions.

 Definitions state the subject matter of the classes and subclasses in
 much more detail than it is possible to state in the brief class and subclass titles. A
 study of the definitions is essential to determine the proper classification of subject
 matter within the U.S. Patent Classification System (USPC).
 

 All classes and subclasses (class definitions) in the USPC are
 available online to USPTO personnel from the Classification Home Page under the heading
 Search Classification Data. The Classification Home Page ( https://ptoweb.uspto.gov/patents/ classification-resources/ ) is
 accessible from the desktop via the Patent Examiner’s Toolkit.
 

 It should be noted that classification orders frequently affect
 existing definitions. Personal sets of definitions used by examiners should be
 periodically revised to reflect these changes. Classification Orders are available
 online to USPTO personnel from the Classification Home Page under the heading Orders.
 The Classification Home Page is accessible from the desktop via the Patent Examiner’s
 Toolkit.
 

 
 902.02(a) Definition Notes in USPC [R-07.2015]

 Many of the definitions have accompanying notes. These notes are of
 two types: (A) notes that supplement definitions by explaining terms or giving
 examples, and (B) notes referring to related disclosures located in other classes or
 subclasses. 
 

 The latter notes are termed “See or Search” notes and are helpful in
 explaining the limits of a class or subclass. They generally state the relationship
 to, and difference from, other identified subject matter collections. Each “See or
 Search” note helps a user reach a decision either to include or exclude an area
 containing relevant subject matter.
 

 Search notes are not exhaustive and do not limit the search but
 suggest additional fields of search. Additionally, since a search note that applies
 to a particular subclass is rarely repeated for subclasses indented thereunder, it is
 advisable to review the search notes of all parent subclasses.
 

 

 
 902.02(b) [Reserved]

 

 

 

 
 902.03 Classification Information [R-07.2022]

 U.S. utility patents and U.S. utility patent application publications
 published after December 31, 2014, do not receive a designated U.S. patent
 classification. U.S. design and plant patents and U.S. plant patent application
 publications receive a designated U.S. patent classification. Current classification
 information for U.S. patents is available from the sources indicated below.
 

 
 902.03(a) Patent Classification Home Page on the Internet [R-01.2024]

 The Office of Patent Classification Home Page address on the
 internet is www.uspto.gov/Classification . The site is the clearinghouse for
 classification information. The site includes the following: (A) links to the
 Cooperative Patent Classification (CPC) system; (B) United States Classification
 (USPC) system resources including class definitions, the USPC index, and the Handbook
 for Classification; and (C) additional classification resources related to
 international classification.
 

 

 
 902.03(b) Patent Classification Home Page on the USPTO Intranet [R-01.2024]

 The address for the Patent Classification Home Page on the USPTO
 intranet is https://ptoweb.uspto.gov/ patents/classification-resources/ . The
 Classification Home Page is also accessible from the desktop via the Patent
 Examiner’s Toolkit. The site is the clearinghouse for classification information by
 the U.S. Patent and Trademark Office (USPTO). Examiners and the public are provided
 with access to identical information for the Index, schedules, and definitions.
 

 The Intranet Classification Home Page site also includes links to
 international information such as CPC schedules, IPC Concordance, IPC Schedules, IPC
 Catchword Index, WIPO Handbook on Industrial Property Information and Documentation,
 and to national (U.S.) information such as Overview of the Classification System,
 Classification Guides and Bulletins, and the Patent Classification Search Page.
 

 

 
 902.03(c) [Reserved] 

 

 

 
 902.03(d) [Reserved]

 

 

 
 902.03(e) Automated Search Tools: PE2E SEARCH [R-01.2024]

 The automated search tool on examiners’ desktop computers is the
 Patents End-to-End (PE2E) Search tool (SEARCH). PE2E SEARCH provides examiners with
 access to the: (A) full text of U.S. published applications since 2001; (B) full text
 of U.S. patents granted since 1970; and (C) optically scanned full text of U.S.
 patents granted 1920-1970. Additionally, PE2E SEARCH provides current classification
 information and images for all U.S. published applications and patents. Images are
 available for foreign patent documents, and English language abstracts are available
 for many foreign patent documents published since 1978 using PE2E SEARCH. Specific
 instructions for gaining access to the various documents can be found on the PE2E
 SEARCH webpage on the intranet, available on examiners’ desktop computers.
 

 The Patent Public Search tool (PPUBS) is available at www.uspto.gov/PatentPublicSearch .
 

 

 

 [top] 

 

 

 
 

 
 

 

 

 

 
 
 
 901-Prior Art 
 901.01-Canceled Matter in U.S. Patent Files 
 901.01(a)-Ordering of Patented and Abandoned Provisional and Nonprovisional Application Files 

 
 

 901.02-Abandoned Applications 

 901.03-Pending Applications 

 901.04-U.S. Patents 
 901.04(a)-Kind Codes 

 
 

 901.05-Foreign Patent Documents 
 901.05(a)-Citation Data 

 901.05(b)-Other Significant Data 

 901.05(c)-Obtaining Copies 

 901.05(d)-Translation 

 
 

 901.06-Nonpatent Publications 
 901.06(a)-Scientific and Technical Information Center (STIC) 

 901.06(b)-Borrowed Publications 

 901.06(c)-Alien Property Custodian Publications 

 901.06(d)-Abstracts, Abbreviatures, and Defensive Publications 

 
 

 901.07-Patent Family Information 

 901.08-Global Dossier Public Access 

 
 

 902-Search Tools and Classification Information 
 902.01-Classification Manual for the U.S. Patent Classification System 
 902.01(a)-Index to the U.S. Patent Classification System 

 
 

 902.02-Class and Subclass Definitions in USPC 
 902.02(a)-Definition Notes in USPC 

 902.02(b)-[Reserved] 

 
 

 902.03-Classification Information 
 902.03(a)-Patent Classification Home Page on the Internet 

 902.03(b)-Patent Classification Home Page on the USPTO Intranet 

 902.03(c)-[Reserved] 

 902.03(d)-[Reserved] 

 902.03(e)-Automated Search Tools: PE2E SEARCH 

 
 

 
 

 903-Classification in USPC 
 903.01-Statutory Authority 

 903.02-Basis and Principles of Classification in USPC 
 903.02(a)-[Reserved] 

 903.02(b)-Scope of a Class in the USPC 

 
 

 903.03-Availability of Foreign Patents 

 903.04-Classifying Applications for Publication as a Plant Patent Application Publication in USPC 

 903.05-Addition, Deletion, or Transfer of U.S. Design Patents by USPC Classification 

 903.06-Harmonized Subclasses 

 903.07-Classifying and Cross-Referencing Design and Plant Applications at Allowance 
 903.07(a)-Cross-Referencing Design and Plant Applications — Keep Systematic Notes During Prosecution 

 
 

 903.08-[Reserved] 
 903.08(a)-[Reserved] 

 903.08(b)-[Reserved] 

 903.08(c)-[Reserved] 

 903.08(d)-[Reserved] 

 903.08(e)-[Reserved] 

 
 

 903.09-[Reserved] 
 903.09(a)-[Reserved] 

 
 

 
 

 904-How to Search 
 904.01-Analysis of Claims 
 904.01(a)-Variant Embodiments Within Scope of Claim 

 904.01(b)-Equivalents 

 904.01(c)-Analogous Arts 

 
 

 904.02-General Search Guidelines 
 904.02(a)-Classified Search 

 904.02(b)-Search Tool Selection 

 904.02(c)-Internet Searching 

 
 

 904.03-Conducting the Search 

 904.04-Search of Related Post-Grant Proceedings 

 
 

 905-Cooperative Patent Classification 
 905.01-Classification Scheme for CPC 
 905.01(a)-CPC Titles 
 905.01(a)(1)-References within CPC Titles 

 905.01(a)(2)-Notes Found in CPC schemes 

 905.01(a)(3)-Warnings Found in CPC schemes 

 905.01(a)(4)-Guidance Headings Found in CPC Schemes 

 
 

 
 

 905.02-CPC Definitions 

 905.03-Classifying in CPC 
 905.03(a)-The CPC Database 

 905.03(b)-Approach to classification in CPC 

 905.03(c)-Combination Sets 

 
 

 
 

 906-International Classification of Patents for Inventions 

 907-Locarno Classification Designations 

 908-[Reserved] 

 909-Routing and Docketing of Applications 
 909.01-Assignment, Transfer and Classification Challenges under Cooperative Patent Classification (CPC) 
 909.01(a)-New Applications in CPC 

 909.01(b)-Classification and Assignment to Examiner in CPC 

 909.01(c)-Immediate Inspection of Amendments 

 909.01(d)-Classification Challenge Procedure in CPC 

 
 

 909.02-Applications: Assignment and Transfer in USPC 
 909.02(a)-New Design and Plant Patent Applications under 35 U.S.C. 161 

 909.02(b)-Classification and Assignment to Examiner 

 909.02(c)-Reserved 

 909.02(d)-Transfer Procedure 

 909.02(e)-General Guidelines Governing the Assignment of Nonprovisional Design and Plant Applications for Examination 

 
 

 
 

 

 

 
 

 
 
 

 
 

 

 
 
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 Last Modified: 
 
 03/09/2026 20:50:54