ARTICLE
10 June 2026

Federal Circuit Affirms Indefiniteness Of The Term “About”

FH
Finnegan, Henderson, Farabow, Garrett & Dunner, LLP

Contributor

Finnegan, Henderson, Farabow, Garrett & Dunner, LLP is a law firm dedicated to advancing ideas, discoveries, and innovations that drive businesses around the world. From offices in the United States, Europe, and Asia, Finnegan works with leading innovators to protect, advocate, and leverage their most important intellectual property (IP) assets.
The Federal Circuit examined whether the term "about" in a patent claim specifying a pH range of "about 7.6 to 10" was sufficiently definite to inform skilled artisans of the invention's scope with reasonable certainty.
United States Intellectual Property
Christine M. Akagi’s articles from Finnegan, Henderson, Farabow, Garrett & Dunner, LLP are most popular:
  • with Senior Company Executives and HR
  • in United States
  • with readers working within the Insurance, Healthcare and Retail & Leisure industries

In Enviro Tech Chemical Services, Inc., v. Safe Foods Corp., No. 2024-2160 (Fed. Cir. May 4, 2026), the Federal Circuit affirmed a district court’s determination that all asserted claims of U.S. Patent No. 10,912,321 were invalid as indefinite.

Enviro Tech sued Safe Foods for infringement of the ’321 patent, which relates to methods of treating poultry during processing to increase weight. The asserted claims recite “a pH of about 7.6 to 10,” and Safe Foods argued that the term “about” is indefinite. The district court agreed, determining that the intrinsic evidence failed to inform a skilled artisan as to the scope of “about” with reasonable certainty.

The Federal Circuit affirmed. First, the Court determined that the claims themselves provided no guidance as to the degree of deviation encompassed by “about.” Second, the Court found that the specification provided conflicting guidance on acceptable pH variance that “about” could encompass because it applied differing deviations in pH ranges across experiments. Third, the Court concluded that statements made during prosecution did not clarify the scope of “about” because Enviro Tech neither defined the term nor applied it consistently, at times arguing it was material to some claims and immaterial to others. The Court also noted that amendments narrowing the claimed pH range to overcome prior art heightened the need for clarity in defining the scope of “about,” reinforcing its conclusion that the claim term is indefinite.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

[View Source]

Mondaq uses cookies on this website. By using our website you agree to our use of cookies as set out in our Privacy Policy.

Learn More