Federal Circuit Reverses Findings of Willful Infringement, Claim Construction, and Infringement by Doctrine of Equivalents

In Laboratory Corporation of America Holdings v. Qiagen Sciences, LLC, No. 23-2350 (Fed. Cir. Aug 13, 2025), the Federal Circuit reversed jury findings of willful infringement of two patents and denial of a renewed motion for judgment as a matter of law.

In the district court, LabCorp alleged Qiagen’s DNA sample preparation kits infringed U.S. Patent Nos. 10,017,810 and 10,450,597, which cover methods for enriching DNA by selectively amplifying a region of interest using target-specific primers and other primers. The jury found Qiagen willfully infringed the ’810 patent under the doctrine of equivalents and willfully and literally infringed the ’597 patent. The court denied JMOL.

For the ’810 patent, the Federal Circuit held the district court erred by allowing the jury to apply a purported plain meaning construction that “identical” primer sequences could mean “identical to a portion.” The Federal Circuit cautioned that juries should not resolve claim construction and held that “‘identical’ cannot mean ‘identical to a portion’ because ‘identical’ means the same,” citing dictionary definitions. The Federal Circuit further recognized “identical” and “identical to a portion” appear in different claim elements, which distinguishes their meaning.

The Federal Circuit also determined the accused products failed the function-way-result test for the ’810 patent and therefore do not infringe under the doctrine of equivalents. The Federal Circuit criticized the district court’s conclusory approach in its JMOL denial, which restated the parties’ arguments and “summarily conclud[ed],” without detailed explanation, that the jury heard sufficient supporting evidence. The Federal Circuit also stressed that the test applies to each individual limitation rather than the claim as a whole. The Federal Circuit found the accused products did not meet the test for certain limitations because they non-selectively amplified a common DNA sequence, while the claims required selective enrichment of the target.

For the ’597 patent, the Federal Circuit held insufficient evidence supported the jury’s finding that the accused primer is a “target-specific primer.” The Federal Circuit found the district court misapplied its own claim construction, which specified the target primer must bind and amplify only target nucleic acids, at JMOL. Because the accused primer could also bind certain non-target sequences common to every DNA fragment in the sample, it failed to infringe under that construction.