Federal Circuit Affirms No Infringement Judgment in Blood Collection Device Dispute

In a precedential March 6, 2026 decision, the Federal Circuit affirmed judgment as a matter of law, or JMOL, of no infringement in favor of Kurin on Magnolia’s asserted blood collection device claims. JMOL is a post-trial ruling that sets aside a jury verdict when the record does not support it as a matter of law. The court also affirmed the district court’s claim construction ruling on Magnolia’s separate patent under 35 U.S.C. § 112(f).

Background

Magnolia asserted two patents covering blood collection devices intended to reduce contamination in blood culture testing. Magnolia sued Kurin in the District of Delaware, alleging that Kurin’s blood collection product infringed U.S. Patent Nos. 10,039,483 and 9,855,001.

The accused product separates the initial blood draw from the portion sent for testing. That design feature mattered because the ’483 patent claimed a “vent” and a “seal,” while the ’001 patent used the term “diverter.” The district court construed “diverter” under Section 112(f), which limits a functional claim term to the structures disclosed in the patent and their equivalents. The parties then stipulated to no infringement of the ’001 patent. The case proceeded to trial on the ’483 patent, where the jury found infringement before the district court later granted JMOL of no infringement.

What the court decided

• The Federal Circuit affirmed construction of “diverter” in the ’001 patent as a means-plus-function limitation under 35 U.S.C. § 112(f).
• The court also affirmed JMOL of no infringement on the ’483 patent, despite the jury’s infringement verdict.
• The court held that the district court clarified, rather than changed, the claims’ plain and ordinary meaning after trial.

Court’s reasoning

1. Separate claim terms can require separate structures. The court focused on claim language reciting both “a seal member” and “a vent.” Because the claim listed those elements separately and joined them with “and,” the court held that the ordinary reading required distinct structures, not one component serving both roles.
2. Post-trial clarification is permissible if it does not alter claim meaning. Magnolia argued that the district court introduced a new construction in ruling on JMOL. The Federal Circuit disagreed. It held that the district court did not rewrite the claims after verdict, but instead clarified what was already inherent in their plain and ordinary meaning.
3. Functional claim language remains vulnerable under Section 112(f). The court agreed that “diverter” in the ’001 patent did not convey enough structure and therefore fell under Section 112(f). That narrowed the claim to the structures disclosed in the specification and their equivalents, which the accused product did not meet.

Practical implications: What companies should do now

The decision highlights how patent outcomes can turn on seemingly modest drafting choices. Patent owners should consider whether separately listed claim elements may later be read to require separate structures. That issue can be dispositive where an accused product uses one component to perform multiple functions. Companies drafting patents, particularly in the medical device and life sciences sectors, should confirm that their claims and specifications support the full range of intended embodiments.

For companies evaluating infringement risk, the case underscores the value of disciplined claim analysis before trial and after verdict. It also reinforces the continuing significance of Section 112(f). Functional language that lacks sufficient structural meaning can narrow claim scope, with direct consequences for enforcement strategy and freedom-to-operate analysis.