United States: Webster Gets a Workout: Dictionary Definitions and the Plain Meaning Rule

The U.S. Court of Appeals for the Federal Circuit reversed a finding non-infringement based on erroneous district court jury instructions relating to the construction of the claim term "non-diffusively bound." Abbott Laboratories v. Syntron Bioresearch, Inc., Case No. 02-1203, -1257 (Fed. Cir. July 10, 2003).

Abbott sued Syntron for infringement of specific claims in two patents relating to the detection and analysis of small amounts of chemical substances in biological fluids. Each of the asserted claims required a "non-diffusively bound reactant" on a medium for detecting an analyte (i.e., a substance to be detected).

The district court instructed the jury using the following definition of "non-diffusively bound": Non-diffusively bound means a reactant immobilized in the reaction zone so as to provide a detectable signal indicating the presence or absence of analyte in the solution, and the reactant is not capable of detaching from the medium, spreading out, and moving along the test strip. "…[A] reactant is non-diffusively bound only if it is found in such a manner that a sufficient and reproducible amount of reactant remains bound in the reactive zone or zones to conduct both quantitative and qualitative assays."

On appeal, Abbott argued that the jury’s finding of non-infringement, based on the failure to satisfy the claim term "non-diffusively bound," was not sustainable because the construction of the claim term "non-diffusively bound" should not have required quantitative analysis of the analyte. Abbott, instead, urged a claim construction that required only that the reactant be immobilized sufficiently to permit detection of the analyte.

The Federal Circuit, citing Texas Digital Sys. v. Telegenix, stated that the first step in the analysis was to determine the ordinary meaning of the claim terms and looked to the dictionary for evidence of a claim term’s ordinary meaning. Looking to Webster’s Dictionary, the Federal Circuit determined that the district court unduly narrowed the plain meaning of the term "non-diffusively bound" in requiring "quantitative analysis" of the analyte, not merely detection.

In addition, the Federal Circuit evaluated the disputed claim term in the context of the claims as a whole and found that the language of the disputed claim term in context, reinforced the plain meaning, i.e., that quantitative analysis should not be read as a requirement of the term "non-diffusively bound." Specifically, the Court noted that each of the asserted claims only required "detecting the presence of analyte," suggesting that this language was broad enough to encompass either qualitative or quantitative analysis, without specifically requiring quantitative analysis.