The Software IP Report

Federal Circuit Again Address Whether “A” is a Singular-Only or Plural-Allowing Interpretation: ABS Global, Inc. v. Cytonome/ST, LLC

In ABS Global, Inc. v. Cytonome/ST, LLC, No. 22-1761 (Fed. Cir. Oct. 19, 2023), the Federal Circuit determined that the PTAB erred in its claim construction of a limitation common to all challenged claims (claims 1, 2, 6, 8, and 9) of U.S. Patent No. 10,583,439 (“the ‘439 patent”).  Ultimately, the court reversed the Board’s written decision with respect to claims 1 and 8, vacated the decision with respect to claims 2, 6, and 9, and remanded the matter to the Board.  

The ’439 patent relates to a microfluidic device for particle processing.  Microfluidic devices use channels for movement of fluids containing cells, molecules, or other particles to, e.g., sort, count, analyze, or test them.

In its opinion, the Federal Circuit stated that, on inter partes review, the Board based determinations of anticipation and obviousness on an incorrect claim construction limiting independent claim 1.  Claim 1 claimed, in part, “a sample stream” and “a fluid focusing region configured to focus the sample stream.”  The Board determined that “a sample stream” requires a singular-only interpretation because a plural-allowing scope would be inconsistent with later claims, i.e., claim 2 of the ‘439 patent.  The court disagreed.

In its analysis, the court concluded that there was strong support for plural-allowing meaning of “a sample stream.”In addition to conventional antecedent basis rules, the court stated that using “a” or “an” before a noun generally allows for the phrase to be construed as “one or more” unless context dictates otherwise.  Additionally, the specification of the ‘439 patent supported a plural-allowing meaning due to the specification including a sentence indicating that “a” or “an” was interchangeable with “one or more” and “at least one” throughout the disclosure.

Ultimately, under the correct claim construction, the court concluded that the evidence required a finding that claims 1 and 8 were anticipated by the prior art, and thus, reversed the Board’s decision on those claims.  With further issues needing to be addressed with claims 2, 6, and 9, the court remanded for further consideration by the Board.

Lessons for Practice

This case is another example of the court’s interpretation of the word “a” and how it can change the interpretation of further claims, e.g., claim 2 here.  As with other cases, the court solidified rules of antecedent basis and the reading of claims in light of the specification in its analysis of “a sample stream” even when the claim term is a simple as the word “a.”  Based on this case and others like it, having clear language in the specification to support the claims and using correct antecedent basis throughout is a safe bet in having the intended interpretation of the claims.