How should examiners handle inventions with multiple classifications?

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.

When dealing with inventions that have multiple classifications, examiners should conduct a comprehensive search across all relevant areas. The MPEP 904.02(a) advises:

“It is not necessary to search all the classes into which the patent document has been placed, or to search all classes in which the claimed subject matter of a patent application would be properly classified.”

However, examiners should:

• Identify the most relevant classifications based on the claimed invention
• Consider additional classifications for unclaimed but disclosed features
• Use their judgment to determine the extent of the search in each classification
• Ensure the search covers the inventive concept and its variations

The goal is to conduct an efficient yet thorough search that captures all relevant prior art.