“A” or “An” Means “One or More” Unless Indicated Otherwise

In ABS Global Inc. v. Cytonome/ST, LLC, No. 22-1761 (Oct. 19, 2023), the Federal Circuit reversed the PTAB’s finding that ABS failed to show that the challenged claims of U.S. Patent No. 10,583,439 are unpatentable based on the construction that “the sample stream” had a singular-only meaning, precluding a plurality of streams or a split stream.

The Federal Circuit disagreed and held that the term “the sample stream” has a plural-allowing meaning. The reference-back language “the” derives its meaning from the antecedent, “a sample stream,” which is plural-allowing. Moreover, in an open-ended “comprising” claim, “a” or “an” before a noun naming an object means “one or more” unless the intrinsic record indicates otherwise. The ’439 patent specification explicitly states that “a” or “an” means one or more and interchangeable with “one or more” and “at least one.” The Federal Circuit held that claim 1 was anticipated because the PTAB’s construction of “the sample stream” was the only basis for its finding that the prior art did not anticipate the claim. As for the other challenged claims, the Federal Circuit vacated and remanded to reconsider the PTAB’s findings on anticipation and obviousness.