Opinion ID: 183481
Heading Depth: 3
Heading Rank: 1

Heading: Step (c)

Text: AMS argues that step (c) does not require the “calculation of a percentage of blood alcohol content.” We agree. AMS asserts that the district court improperly treated the preamble language “monitoring the percentage of blood alcohol content” as a limitation by requiring a calculation of BAC in step (c). Generally, a preamble does not limit the scope of claims unless “it recites essential structure or steps, or if it is necessary to give life, meaning, and vitality to the claim.” See, e.g., Am. Med. Sys., Inc. v. Biolitec, Inc., 618 F.3d 1354, 1358 (Fed. Cir. 2010) (internal citations omitted). We previously held that a preamble is not limiting where it “merely gives a descriptive name to the set of limitations in the body of the claim that completely set forth the invention.” IMS Tech., Inc., 206 F.3d at 1434-35 (Fed. Cir. 2000). Here, “monitoring the percentage of blood alcohol” is such a descriptive name and does not additionally limit the scope of the claims. Furthermore, the district court’s construction of step (c) is difficult to reconcile with the fact that devices that measure alcohol emitted through the skin do not actually calculate a BAC, but instead calculate a TAC, which approximates BAC. The plain language of the claim, “percentage of alcohol expelled through the subject’s skin,” indicates that the measurement is not BAC, which is only measured by a blood sample, but instead is TAC. Indeed, Defendants admit that the claimed method calculates TAC, a percentage that provides an indication of BAC. Therefore, to the extent the claim requires a calculation of a percentage, that percentage only approximates BAC (e.g., TAC). However, AMS further contends that the term “per- centage” does not require any calculation, but instead is a “percentage of alcohol expelled through the subject’s skin 9 ALCOHOL MONITORING v. ACTSOFT into said measurement device.” In other words, AMS contends that the term refers to the measured sample, which is not all of the alcohol expelled through the subject’s skin, but only the “percentage” that enters “into said measurement device.” Under AMS’s proposed construction, the “percentage” is not a quantifiable measurement. A person of skill in the art would be unable to calculate what “percentage” of alcohol went into the measurement device, compared to the total alcohol expelled through the body in its entirety. Even if the device could conceivably quantify the amount of alcohol entering into the device, the device could not determine the total quantity of alcohol expelled through the body. Because AMS’s proposed construction is not quantifiable, it conflicts with claims 19 and 21, which depend from claim 14. Claims 19 and 21 require storing an interferant indication “if a change in said percentage of alcohol exceeds a predetermined . . . rate.” It logically follows that the claimed percentage must itself be a numerical value or one could not compare “a change in said percentage” to “a predetermined rate” as required by the dependent claims. Therefore, claim 14 requires the actual calculation of a percentage and AMS’s proposed construction cannot be correct. Thus, properly construed, step (c) requires the measurement of an amount of alcohol being emitted from an individual’s skin and the calculation of a percentage that approximates blood alcohol content (e.g., transdermal alcohol content). This construction is consistent with both the intrinsic record and the extrinsic testimony from AMS’s inventor and expert witness. ALCOHOL MONITORING v. ACTSOFT 10