"an" + "consists of" = "one and only one"
Monday, June 1, 2009 at 6:20 PM
Justin E. Gray in Federal Circuit

Digene Corp. v. Third Wave Techs., Inc. (Fed. Cir. April 1, 2009)

In this case, the Federal Circuit, in an opinion by Judge Lourie, found that the district court (Western District of Wisconsin) did not err in its determinative claim constructions relating to a patent concerning diagnosis of human papillomavirus ("HPV") type 52 (a primary cause of cervical cancer).

The claim element at issue was "HPV 52 DNA consists of all or a fragment of an HPV DNA." The district court construed "HPV 52 DNA" as "a DNA molecule that is only type 52 HPV" and "consists of all or a fragment of an HPV DNA" as "consists of all or a fragment of one HPV DNA that does not contain any other DNA."

Digene argued that "HPV 52 DNA" should not be limited to a molecule that is only HPV type 52. The Federal Circuit disagreed, focusing its analysis on the fact that during prosecution, Digene explicitly stated that "the claimed HPV 52 DNA must be derived from only type 52 HPV DNA." Therefore, prosecution disclaimer applied and Digene therefore disclaimed any meaning of "HPV 52 DNA" that was derived from anything but HPV 52 DNA.

Next, Digene argued that the term "consists of all or a fragment of an HPV DNA" should not be limited to "one and only one HPV DNA" because the word "an" in the claim should be construed to mean "one or more." However, the Federal Circuit noted that when the term "consists of" appears in the body of a claim, it "limit[s] the clause for which it acts as a transition to only those elements found in that particular clause" and it "generally requires that the word 'an' following it be limited to one and only one."

While the constructions of other claim terms were disputed by Digene, it had conceded during oral argument that it could not prove infringement under the district court's construction of "HPV 52 DNA consists of all or a fragment of an HPV DNA." Since the Federal Circuit affirmed the district court's construction of that term, further analysis was not necessary.

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Article originally appeared on A Claim Construction and Patent Law Blog (http://www.grayonclaims.com/).
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