In Nautilus, Inc. v. Biosig Instruments, Inc., issued on June 2, 2014, the Supreme Court established a new legal test to determine whether a patent claim satisfies the definiteness requirement of 35 U.S.C. Section 112. More specifically, the Court held “that a patent is invalid for indefiniteness if its claims, read in light of the specification delineating the patent, and the prosecution history, fail to inform, withreasonable certainty, those skilled in the art about the scope of the invention.” (Slip Op. at 1) (emphasis added). The Court also stated that the Federal Circuit’s previous test of indefiniteness, i.e., that a claim was definite so long as the claim is “amenable to construction” and is not “insolubly ambiguous,” does not satisfy the statute’s definiteness requirement. Id. While stating the test to be applied, the Court left it to the Federal Circuit to apply that test in this particular case by remanding the ultimate determination on (in)definiteness. Id. at 14.

Based on the Court’s holding, the key questions raised would, at first blush, seem to be: (1) what constitutes a reasonable certainty to those skilled in the art? and (2) is the “scope of the invention” a broader construct than merely focusing on claim construction of a particular claim term? Given the Court’s remand, no particular guidance was given on these issues at present. Nevertheless, given that the Court’s opinion stated that “[o]ne must bear in mind . . . that patents are ‘not addressed to lawyers, or even to the public generally,’ but rather to those skilled in the relevant art,” Id. at 9 (citations omitted), the Court’s test seems to open the door for an increase in the presentation of expert testimony regarding claim clarity. Notably, despite this implication (and the Court’s citation toMarkman and the indication that claim construction “may turn on evaluations of expert testimony” on page 11 of the opinion), the Court left for another day the appropriate standard of evidentiary review on definiteness. Id. at 13, n. 10.

The practical implications of the Nautilus decision seem to be: (1) the interpretation of the test has been left in the first instance to the Federal Circuit and the district courts, and (2) given the need to interpret the test, the number of invalidity challenges based on indefiniteness are likely to increase because the previous standard “tolerate[d] some ambiguous claims but not others.” Id. at 1. It is likely that claim construction proceedings (and the corresponding indefiniteness challenges) will see more expert declarations and/or reports submitted given the focus of the test on “those skilled in the art.” Additionally, arguments that the scope of the overall claim is unclear (even if the specific terms of a claim are capable of construction) also may become more frequent.