How can the preamble provide antecedent basis for claim terms?

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.

The preamble can provide antecedent basis for claim terms, which is an important consideration in determining whether the preamble limits the scope of a claim. According to MPEP 2111.02:

“Preamble statements reciting the purpose or intended use of the claimed invention must be evaluated to determine whether or not the recited purpose or intended use results in a structural difference (or, in the case of process claims, manipulative difference) between the claimed invention and the prior art.“

When the preamble provides antecedent basis:

• It introduces terms that are later referenced in the body of the claim.
• These terms become essential for understanding the claim’s scope and limitations.
• The preamble is likely to be considered limiting because it’s necessary for claim coherence.

For example, if a preamble mentions “a hollow tube” and the body of the claim refers to “said tube,” the preamble is providing antecedent basis and is likely to be limiting. This relationship between the preamble and the claim body can be crucial in patent infringement cases and claim interpretation disputes.