How does the MPEP address “Markush” groupings in patent claims?

The MPEP addresses “Markush” groupings in patent claims in MPEP 2173.05(h). A Markush grouping is a closed group of alternatives, and is typically expressed as “a material selected from the group consisting of A, B, and C.” The MPEP states:

“Treatment of claims reciting alternatives is not governed by the particular format used (e.g., alternatives may be set forth as “a material selected from the group consisting of A, B, and C” or “wherein the material is A, B, or C”).”

This means that the substance of the claim, rather than its specific phrasing, determines how it will be treated. The MPEP further clarifies that a Markush grouping is proper if:

• The members of the group belong to a recognized physical or chemical class or an art-recognized class
• The members are disclosed in the specification or known in the art to be functionally equivalent
• The members have a common property or activity

Understanding Markush groupings is crucial for patent drafters and examiners to ensure clear and proper claim language.

To learn more:

• Markush grouping
• alternative limitations
• patent claims
• MPEP 2173.05(h)