MPEP § 902.01(a) — Index to the U.S. Patent Classification System (Annotated Rules)

§902.01(a) Index to the U.S. Patent Classification System

USPTO MPEP version: BlueIron's Update: 2025-12-31

This page consolidates and annotates all enforceable requirements under MPEP § 902.01(a), including statutory authority, regulatory rules, examiner guidance, and practice notes. It is provided as guidance, with links to the ground truth sources. This is information only, it is not legal advice.

Index to the U.S. Patent Classification System

This section addresses Index to the U.S. Patent Classification System. Contains: 2 guidance statements and 1 other statement.

Key Rules

Topic

Sequence Listing Requirements

3 rules
MPEP GuidanceInformativeAlways
[mpep-902-01-a-585fe20c5c63253d4ce7e525]
Index to U.S. Patent Classification System Used for Initial Entry
Note:
The index is used as an initial entry into the system but should not be considered exhaustive; all appropriate class schedules and definitions must still be reviewed.

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.

Jump to MPEP SourceSequence Listing Requirements
MPEP GuidanceRecommendedAlways
[mpep-902-01-a-c73a0a5327d4053cffafc36b]
Index Not Exhaustive for USPC Search
Note:
The index is used as an initial entry into the U.S. Patent Classification System but should be supplemented by scanning all appropriate class schedules and reviewing pertinent classifications.

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.

Jump to MPEP SourceSequence Listing Requirements
MPEP GuidanceRecommendedAlways
[mpep-902-01-a-20f2f170d42821aa611c4a16]
Review Class Schedules and Subclasses Even When Index Citation Seems Specific
Note:
When using the USPC index, review all related class schedules and their definitions even if the initial citation appears to cover only a specific subject area.

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.

Jump to MPEP SourceSequence Listing Requirements

Source Text from USPTO’s MPEP

This is an exact copy of the MPEP from the USPTO. It is here for your reference to see the section in context.

BlueIron Last Updated: 2025-12-31