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.
“Lack of antecedent basis” refers to a situation in patent claims where a term is used without proper introduction or reference to a previously mentioned element. As stated in MPEP 2173.05(e):
“The lack of clarity could arise where a claim refers to ‘said lever’ or ‘the lever,’ where the claim contains no earlier recitation or limitation of a lever and where it would be unclear as to what element the limitation was making reference.”
This issue can lead to indefiniteness in claims, potentially rendering them unclear and therefore invalid under 35 U.S.C. 112(b).