Pharma Tech Solutions, Inc. v. LifeScan, Inc., No. 19-1163 (Fed. Cir. 2019)Annotate this Case
Pharma Tech sued LifeScan for infringement of two patents that concern blood glucose monitoring systems for home use by individuals with diabetes. The shared specification of Pharma Tech’s patents states that the claimed inventions improve on prior art blood glucose monitoring systems by “eliminat[ing] several of the critical operator depend[e]nt variables that adversely affect the accuracy and reliability” of these systems. The specification explains that the invention accomplishes this objective by performing multiple Cottrell current measurements and comparing the results. “In a system that is operating correctly, the results should agree within reasonable limits.” The Federal Circuit affirmed summary judgment of noninfringement. Pharma Tech agreed that the accused products do not literally infringe the claim. Prosecution history estoppel bars the claims for infringement under the doctrine of equivalents; the accused system falls within the claim scope surrendered by the inventors during prosecution of the patent.