How do transitional phrases affect the interpretation of Markush groups in patent claims?

How do transitional phrases affect the interpretation of Markush groups in patent claims?

Transitional phrases can significantly impact the interpretation of Markush groups in patent claims:

• “Consisting of” with Markush groups: Limits the claim to only the listed members of the Markush group.
• “Comprising” or “including” with Markush groups: Generally interpreted as open-ended, allowing for additional elements beyond those listed.

The MPEP 2111.03 states:

“A claim element defined by selection from a group of alternatives (a Markush grouping; see MPEP § 2117 and § 2173.05(h)) requires selection from a closed group ‘consisting of’ (rather than ‘comprising’ or ‘including’) the alternative members.“

However, the interpretation can vary based on the specific language used and the context of the invention. Examiners and practitioners should carefully consider the transitional phrase when evaluating the scope of Markush groups in claims.

To learn more:

• transitional phrases
• Markush groups
• consisting of
• comprising
• including
• claim interpretation