Magnolia Medical Technologies, Inc. v. Kurin, Inc.

Magnolia Medical Technologies v. Kurin, decided March 6th, 2026. A precedential panel of the Federal Circuit, in an opinion by Judge Lourie, issued two claim-construction holdings. Claim limitations listed separately, a seal member and a vent, presumptively require separate structures. And the term diverter, though it does not use the word means, is a means-plus-function term, because the claim recites no structure that performs its function. The court affirmed judgment for Kurin. Here's the brief.

Both Magnolia patents concern devices that improve the accuracy of blood tests. Skin microbes tend to contaminate the first portion of drawn blood, producing false positives. The patented devices divert and sequester that initial portion.

Kurin makes the Kurin Lock. Initial blood flows into a side channel ending in a porous plug. While dry, the plug lets air escape. When blood reaches it, the plug swells shut and seals the channel. One structure serves first as a vent, then as a seal.

A jury found that the Kurin Lock infringed Magnolia's ’483 patent, but the district court granted judgment as a matter of law of no infringement. On the ’001 patent, the court had construed diverter as a means-plus-function term, and the parties stipulated to noninfringement. Magnolia appealed both rulings.

Two frameworks governed. For separately listed limitations, the court looked to its 2010 decision in Becton, Dickinson v. Tyco Healthcare.

For means-plus-function claiming, the court applied its en banc decision in Williamson v. Citrix. A term without the word means is presumed not to invoke section 112(f). That presumption is overcome if the challenger shows the term fails to recite sufficiently definite structure, or recites function without sufficient structure for performing it.

On the ’483 patent, the court first rejected Magnolia's argument that the separate-structure requirement was an untimely, post-verdict construction. The parties had agreed to plain meaning, and under Becton the requirement was inherent in that meaning; the district court only clarified it.

The text confirmed it. The claim uses the comprising-a format, and the two limitations are joined by and. The specification describes the seal and the vents only as separate structures. Dependent claim 6, which recites separate seal and vent elements, did not force claim 1 to be broader, because a dependent claim may narrow one limitation without being narrower in every respect. Magnolia's alternative theory, that a different part of the device was the seal, had never been presented to the jury.

On the ’001 patent, the parties agreed that a diverter's function is to direct bodily fluid down one of two paths. The claim recites an inlet and two outlets.

Magnolia's expert testified that a diverter includes at least one inlet and two outlets. The court treated that as an admission: every diverter has those parts; the question was what directs the flow.

Magnolia v. Kurin applies two established rules. Under Becton, separately listed claim elements presumptively require distinct structures, and that requirement inheres in the claim's plain meaning. Under Williamson, a functional claim term without the word means can still invoke section 112(f) where the structure the claim does recite is passive and does not perform the claimed function. Expert testimony that a term covers any structure capable of the function supports, rather than defeats, that conclusion.

Magnolia Medical Technologies, Inc. v. Kurin, Inc., 169 F.4th 1094, decided March 6th, 2026. I'm Kyle Coleman. Thanks for watching.