How does double inclusion affect claim indefiniteness?

Double inclusion can potentially affect claim indefiniteness, but it doesn’t automatically render a claim indefinite. According to MPEP 2173.05(o):

“The facts in each case must be evaluated to determine whether or not the multiple inclusion of one or more elements in a claim gives rise to indefiniteness in that claim.”

The MPEP provides examples to illustrate this point:

• In Markush groups, double inclusion does not necessarily lead to indefiniteness: “The mere fact that a compound may be embraced by more than one member of a Markush group recited in the claim does not lead to any uncertainty as to the scope of that claim for either examination or infringement purposes.”
• However, in device claims, double inclusion might cause indefiniteness: “Where a claim directed to a device can be read to include the same element twice, the claim may be indefinite.”

Patent drafters and examiners should carefully consider whether double inclusion creates ambiguity in the claim’s scope or interpretation.

To learn more:

• double inclusion
• claim indefiniteness
• Markush groups
• device claims
• claim interpretation