Patent Case Summaries | Week Ending May 8, 2026

Why It Matters

The ruling signals that vague approximations like “about” can invalidate biotech and food‑processing patents, prompting tighter claim drafting and heightened litigation risk.

Key Takeaways

• Federal Circuit affirmed indefiniteness of “about” in pH claim range
• Specification’s conflicting data failed to define “about” precisely
• Prosecution history offered no clear definition, reinforcing indefiniteness
• Court stressed tighter language after amendment to avoid prior art

Pulse Analysis

The May 4, 2026 opinion in Enviro Tech Chemical Services v. Safe Foods highlights the Federal Circuit’s continued scrutiny of indefinite claim language. While terms such as “about” and “approximately” are permissible, the court requires that the underlying range be anchored by a reasonably certain technical basis. In this case, the patent’s claim recited a pH of about 7.6 to about 10, yet the specification presented experiments with deviations ranging from 0.3 to 0.5 pH units, offering no consistent metric for a skilled artisan to determine the scope. Coupled with an inconsistent prosecution history, the court concluded the term was indefensible under § 112.

For practitioners drafting patents in chemical, food‑processing, and broader biotech fields, the decision serves as a cautionary tale. Precise numerical boundaries, or at minimum a well‑documented empirical justification for any approximation, are essential. When a claim is amended to sidestep prior art—as Enviro Tech did to distance itself from a prior‑art pH of 7.0—the need for clarity intensifies. Patent drafters should embed clear experimental thresholds, define permissible deviations, and ensure that the specification and prosecution record consistently reinforce the chosen language.

The broader industry impact is twofold. First, litigators can now leverage this precedent to challenge patents that rely on vague approximations, potentially increasing invalidity defenses in infringement suits. Second, companies seeking to license or acquire technology must scrutinize claim language for definiteness, as ambiguous terms may diminish a patent’s enforceability and valuation. As the Federal Circuit continues to enforce stricter standards, the balance shifts toward more exacting claim construction, encouraging innovators to invest in robust, data‑driven disclosures early in the patent process.