by Dennis Crouch
Five years ago, I posed this question: How does the printed matter doctrine apply to letters that can only be read using an X-ray? Dennis Crouch, Patent Eligibility of Claims Directed to Printed Matter, Patently-O (Nov. 11, 2020). The Federal Circuit’s first decision in the long-running C.R. Bard v. AngioDynamics litigation had held that the informational content conveyed by radiographic markers on vascular access ports constitutes printed matter not entitled to patentable weight, but that the structural requirement of a radiographically discernible marker could still distinguish the claims from prior art. C R Bard Inc. v. AngioDynamics, Inc., 979 F.3d 1372 (Fed. Cir. 2020). The case went back for retrial, the jury again sided with the patentee on validity, and the district court again granted judgment as a matter of law rejecting the jury verdict. Now the Federal Circuit has affirmed, but on anticipation rather than eligibility grounds, and in doing so has clarified just how little remains of these claims once the printed matter is stripped away. C.R. Bard, Inc. v. AngioDynamics, Inc., No. 2023-2056 (Fed. Cir. Dec. 15, 2025) (per curiam, nonprecedential).
The patents at issue claim assemblies and methods for identifying “power injectable” vascular access ports. These are devices implanted beneath a patient’s skin that allow medical providers to inject fluids directly into the veins. Power injection involves high-pressure, high-flow-rate delivery of contrast agents during CT imaging. Following a 2005 FDA warning about port failures during power injection, Bard developed ports with radiographic markers (the letters “CT” etched in titanium foil) that would appear on x-ray scout scans, allowing clinicians to confirm the port was rated for power injection before use. Representative claim 1 of US8475417 recites an assembly with “a first identifiable feature … identifying the access port as suitable for flowing fluid at a [high] fluid flow rate” and “a second identifiable feature … identifying the access port as suitable for accommodating a [high] pressure” where “one of the first and second features is a radiographic marker perceivable via x-ray.” Dependent claim 5 further requires that “the radiographic marker is one or more radiographic letters.”
The printed matter doctrine has become one of patent law’s more complex areas, operating at the intersection of subject matter eligibility under Section 101 and the novelty and nonobviousness inquiries under Sections 102 and 103. The doctrine’s core principle is that claim limitations directed to the content of information are not entitled to patentable weight unless that information has a “functional relationship” to its substrate. As the Federal Circuit explained in In re Gulack, 703 F.2d 1381 (Fed. Cir. 1983), the question is “whether there exists any new and unobvious functional relationship between the printed matter and the substrate.” In Gulack, the court found such a relationship where digits printed on an endless wristband embodied a mathematical sequence; the physical structure of the band placed the numbers in specific spatial relationships that satisfied the claimed algorithm. But where information merely labels or describes the substrate without altering how the substrate functions, it receives no patentable weight.
The Functional Relationship Test The printed matter doctrine asks two questions: (1) Is the claim limitation directed to printed matter, i.e., information claimed for its communicative content? (2) If so, is the printed matter functionally related to its substrate?
Two relatively recent decisions illustrate the doctrine’s application to informational content that goes beyond traditional “printed” material. In Praxair Distribution, Inc. v. Mallinckrodt Hospital Products IP Ltd., 890 F.3d 1024 (Fed. Cir. 2018), the Federal Circuit addressed claims to methods of distributing nitric oxide gas cylinders for pharmaceutical use. The claims required “providing information” to medical providers about recommended dosing and warnings that certain patients with pre-existing heart conditions faced elevated risks of pulmonary edema. The court held that these informational limitations constituted printed matter because they were “directed to the content of information” rather than to any structural or functional aspect of the gas delivery system. The information did not change how the nitric oxide functioned or how the delivery apparatus operated; it merely told clinicians something about the product’s appropriate use. Judge Newman concurred in the ultimate judgment of obviousness but objected that the majority had improperly stretched the doctrine beyond its historical bounds, writing that the printed matter doctrine should be “limited to printed matter, not information and not mental steps.”
Later that same year, In re Marco Guldenaar Holding B.V., 911 F.3d 1157 (Fed. Cir. 2018), applied the doctrine to reject claims for a dice game where the inventive concept resided in how many faces of each die bore markings. The applicant argued that the specifically marked dice were unconventional and constituted “significantly more” than the abstract idea of game rules. The court disagreed, reasoning that the markings on the dice “communicate[] information to participants indicating whether the player has won or lost a wager” and “are not functionally related to the substrate of the dice.” The dice remained ordinary dice; the markings did not alter their physical properties or mechanical operation. This stands in contrast to In re Gulack, where the endless band substrate itself placed the printed digits in a unique physical arrangement that embodied the mathematical relationship. In Guldenaar, any set of dice could bear the claimed markings, and the markings served only to communicate game outcomes to human players. The court drew an express analogy to labels on products: “similar to the markings on a typical die or a deck of cards.”
The Bard claim language sits uncomfortably between these precedents. The claims recite “an assembly for identifying a power injectable vascular access port” comprising: a port with standard structural elements (body, cavity, septum, outlet); a “first identifiable feature” that “identif[ies] the access port as suitable for flowing fluid at a fluid flow rate of at least 1 milliliter per second”; a “second identifiable feature” that “identif[ies] the access port as suitable for accommodating a pressure within the cavity of at least 35 psi”; and a “third identifiable feature separated from the subcutaneously implanted access port” confirming both characteristics. The claim requires that “one of the first and second features is a radiographic marker perceivable via x-ray.” Notice the word “identifying” does substantial work here. The features do not make the port capable of the claimed flow rates and pressures; they identify the port as already having those capabilities. This is label language, not structure language. The preamble reinforces the point: the assembly is “for identifying” a power injectable port, not for creating one.
The radiographic markers themselves are not traditional ink-on-paper printed matter; they are titanium foil etchings readable only via x-ray. The first Federal Circuit decision acknowledged this, holding that “the focus of the claimed advance is not solely on the content of the information conveyed, but also on the means by which that information is conveyed.” The radiographic nature of the marker “allows the implanted device to be readily and reliably identified via x-ray, as used during CT imaging.” That structural feature, the court reasoned, gave the claims more than mere printed matter. But the court simultaneously held that “the content of the information conveyed by the claimed markers, i.e. that the claimed access ports are suitable for injection at the claimed pressure and flow rate, is printed matter not entitled to patentable weight.” This created a doctrinal tension: the marker’s radiographic visibility was entitled to weight, but its meaning was not.
The new decision resolves that tension in favor of the prior art. Writing per curiam, the panel (Judges Lourie, Reyna, and Chen) concluded that once the informational content is stripped away, the claims require nothing more than “a radiographically discernible feature.” What remains after applying the printed matter doctrine is simply a requirement that the port have some feature visible on x-ray. And Bard’s own predecessor product had such features.
The dependent claims fared no better. Claim 5 of the ‘417 patent requires “radiographic letters,” and the district court had determined that a letter “intrinsically conveys its typographical meaning.” The Federal Circuit agreed that the letter aspect of the claimed radiographic letter is printed matter claimed for its communicative content. The court analogized to Guldenaar: just as the dice markings communicated win/loss information without changing how the dice functioned, the radiographic letters communicate power-injectability information without altering the port’s structural capabilities. The letters “do not cause the [port] itself to become a manufacture with new functionality.” Similarly, the method claim’s step of “identifying [an] indicating radiographic feature on [an] x-ray” merely requires identifying a radiographically discernible feature; any requirement that the feature convey information about the port’s capabilities “is merely a mental step to recognize printed matter, which is also not entitled to patentable weight” under Praxair.
This case also continues the Federal Circuit’s pattern of granting judgment as a matter of law on issues that juries have resolved in favor of patentees. After the first appeal, the case was retried, and the jury found willful infringement and rejected all invalidity defenses. The district court nevertheless granted JMOL on anticipation, indefiniteness, and ineligibility. The Federal Circuit affirmed on anticipation alone, declining to reach the other grounds. Anticipation is nominally a question of fact, Voda v. Cordis Corp., 536 F.3d 1311, 1322 (Fed. Cir. 2008), yet the court found that Bard’s own stipulations, expert admissions, and exhibits left “no genuine dispute for the jury.”
The opinion is nonprecedential, but its reasoning flows directly from the court’s 2020 decision in the case and from Praxair and Guldenaar. The printed matter doctrine does not merely limit patentability of ink on paper; it limits patentability of information claimed for what it tells humans, regardless of the medium through which that information is conveyed.