IP Law Daily, PATENT—Fed. Cir.: Qiagen did not infringe Labcorp's DNA sequencing preparation patents; $4.7M jury verdict reversed, (Aug 14, 2025)

By Saurabh Kashyap, B.A., M.A., LL.B., LL.M.

The district court erred in permitting jury findings on claim scope and equivalence unsupported by law and evidence.

The U.S. Court of Appeals for the Federal Circuit reversed a $4.7 million jury verdict in favor of Laboratory Corporation of America Holdings and its affiliates, ruling that Qiagen Sciences LLC and related entities did not infringe two DNA sequencing sample preparation patents. The appellate court held that the evidence presented at trial was insufficient to support the jury's finding of infringement—whether under the doctrine of equivalents for U.S. Patent No. 10,017,810 (the '810 patent) or by literal infringement of U.S. Patent No. 10,450,597 (the '597 patent). It found that the district court erroneously delegated claim construction to the jury and allowed legally insufficient theories of equivalence. Consequently, the Federal Circuit reversed the district court's denial of Qiagen's renewed motion for judgment as a matter of law (JMOL) and directed that judgment of non-infringement be entered in Qiagen's favor (Laboratory Corporation Of America Holdings v. Qiagen Sciences, LLC, No. 23-2350 (Fed. Cir. Aug. 13, 2025)).

Background. The plaintiffs/appellees, Laboratory Corporation of America Holdings and Labcorp Genetics, Inc., are leading providers of clinical diagnostics services in the United States. Labcorp acquired ArcherDX, LLC, which originally owned the patents at issue. Massachusetts General Hospital, operating under The General Hospital Corporation, was a co-owner of the patents. The defendants/appellants, Qiagen Sciences LLC, Qiagen LLC (formerly Qiagen, Inc.), and other related companies, are affiliates of Qiagen N.V., a global molecular diagnostics firm specializing in sample preparation technologies and assay development.

The asserted ’810 and ’597 patents describe methods for preparing DNA fragments for sequencing by enriching specific genomic regions to improve efficiency and reduce costs. The ’810 patent discloses ligating a universal adaptor to DNA fragments, followed by two PCR amplification rounds using distinct primer pairs to target regions of interest. The ’597 patent builds on this by replacing one adaptor with a set of primers sharing a common 5′ sequence but differing 3′ sites, enabling selective amplification of target strands. This refinement reduces non-specific amplification and enhances compatibility with sequencing platforms.

Labcorp filed the original suit in July 2018 in the District of Delaware, asserting the ’810 patent. Following the issuance of the ’597 patent, Labcorp amended the complaint to include additional infringement claims. The accused Qiagen products included DNA sample preparation kits containing forward primers (FP), universal primers (UP), gene-specific primers (GSP), and sample index primers (SIP). Labcorp alleged that various combinations of these primers infringed the asserted claims of both patents.

After a five-day jury trial in August 2021, the jury found Qiagen liable for willfully infringing claims 16, 17, and 19 of the ’810 patent under the doctrine of equivalents, and claims 1, 5, and 19 of the ’597 patent by literal infringement. The jury awarded Labcorp $4.7 million in damages. The district court subsequently denied Qiagen’s renewed motion for JMOL and a new trial. Qiagen appealed.

Claim construction error. The Federal Circuit began by reviewing the district court’s decision to allow the jury to determine the meaning of the term “identical” in the ’810 patent’s claim limitation requiring the “second target-specific primer” to have a 5′ region “identical to a second sequencing primer.” Qiagen’s SIP contained only a subset of the sequencing primer’s nucleotide sequence. Labcorp’s theory—accepted by the district court—was that “identical” could mean “identical to a portion of.”

The appellate court disagreed. Citing O2 Micro Int’l Ltd. v. Beyond Innovation Tech. Co., 521 F.3d 1351 (Fed. Cir. 2008), the court emphasized that the proper interpretation of claim terms is a matter of law to be decided by the judge, not the jury. The Federal Circuit held that "identical" means fully and precisely the same in sequence and length. It distinguished this from the separate claim language that referred to a sequence "identical to a portion of," which appeared elsewhere in the patent. Drawing on Seachange Int’l, Inc. v. C-COR, Inc., 413 F.3d 1361 (Fed. Cir. 2005) and Arlington Indus., Inc. v. Bridgeport Fittings, Inc., 632 F.3d 1246 (Fed. Cir. 2011), the court concluded that conflating the two would nullify the distinction between complete identity and partial identity. Thus, the SIP could not satisfy the "identical" requirement as a matter of law.

Doctrine of equivalents. Labcorp also asserted that the SIP infringed the ’810 patent under the doctrine of equivalents. Applying the function-way-result test, the Federal Circuit found that Labcorp’s evidence failed on all three prongs.

First, the SIP served a different function: it did not enrich the DNA sample for the target sequence but merely enabled sequencing by annealing to a tail added by the GSP. Second, the method by which the SIP operated was different from the claimed second target-specific primer, which was designed to anneal directly to the native DNA target sequence. Third, the result differed because the SIP indiscriminately amplified both target and non-target sequences, whereas the patented method was designed to suppress off-target amplification. Citing VLSI Tech. LLC v. Intel Corp., 87 F.4th 1332 (Fed. Cir. 2023), the appellate court concluded that Labcorp failed to offer the “particularized testimony and linking argument” required to prove equivalence.

Literal infringement. With regard to the ’597 patent, the Federal Circuit addressed whether Qiagen’s FP qualified as a “target-specific primer” under the court’s construction, which required the primer to anneal to and amplify only the target nucleic acid and not any non-target sequences. Qiagen’s FP annealed to adaptor sequences that were identical across all DNA fragments in the sample, including non-target DNA.

The appellate court held that this universal binding meant the FP could not satisfy the specificity requirement. The court rejected Labcorp’s argument that the FP worked in conjunction with the GSP to achieve specificity. Citing In re Power Integrations, Inc., 884 F.3d 1370 (Fed. Cir. 2018), the Federal Circuit clarified that each claim element must independently meet the claimed function unless the claim expressly provides otherwise. Because the FP, standing alone, could bind to non-target sequences, it did not satisfy the claim limitation, and no reasonable jury could have found literal infringement.

Disposition. Concluding that no substantial evidence supported the jury’s findings of infringement for either patent, the Federal Circuit reversed the district court’s denial of JMOL and ordered judgment of non-infringement on both the ’810 and ’597 patents.

The Case is No. 23-2350.

Judge: Lourie, A.

Attorneys: Edward R. Reines (Jones Day) for Laboratory Corp. of America Holdings, Labcorp Genetics, Inc., and The General Hospital Corporation d/b/a Massachusetts General Hospital. David Leon Bilsker (Quinn Emanuel Urquhart & Sullivan, LLP) for Qiagen Sciences, LLC, Qiagen LLC, Qiagen Beverly, LLC, Qiagen Gaithersburg, LL, Qiagen GmbH, and Qiagen N.V.

Companies: Laboratory Corp. of America Holdings; Labcorp Genetics, Inc.; The General Hospital Corporation d/b/a Massachusetts General Hospital; Qiagen Sciences, LLC; Qiagen LLC; Qiagen Beverly, LLC; Qiagen Gaithersburg, LLC; Qiagen GmbH; Qiagen N.V.

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