How does an examiner determine lack of unity in a national stage application?

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 determining lack of unity in a national stage application, an examiner must follow specific steps as outlined in MPEP 1893.03(d):

1. List the different groups of claims
2. Explain why each group lacks unity with each other group
3. Specifically describe the unique special technical feature in each group

The MPEP states: “When making a unity of invention requirement, the examiner must (1) list the different groups of claims and (2) explain why each group lacks unity with each other group (i.e., why there is no single general inventive concept) specifically describing the unique special technical feature in each group.”

Examiners use form paragraphs, such as 18.18, 18.19, and 18.20, to communicate lack of unity determinations to applicants. These paragraphs provide standardized language for restriction requirements and species elections in national stage applications.