This case is about an appeal by DNA Genotek Inc. against a district court's ruling of non-infringement in a patent dispute with Spectrum Solutions LLC. The case revolves around U.S. Patent No. 10,619,187, which covers devices and methods for preserving nucleic acids. The core issue is the interpretation of the term "reagent compartment" within the patent's claims. The lower court construed this term to mean a region within the containment vessel, a construction Genotek disputes. The Court of Appeals ultimately affirms the lower court's construction, finding support in the patent's specification and prosecution history. The court concluded that Genotek had limited the patent's scope by intentionally omitting a design with the reagent in the cap.