**United States Court of Appeals for the Federal Circuit**

03-1370

HOME DIAGNOSTICS, INC.,

> Plaintiff-Appellee,

v\.

LIFESCAN, INC.,

Defendant-Appellant.

[Barbara C. McCurdy]{.underline}, Finnegan, Henderson, Farabow, Garrett
& Dunner, L.L.P., of Washington, DC, argued for plaintiff-appellee. With
her on the brief were [Herbert H. Mintz]{.underline} and [Kathleen A.
Daley]{.underline}.

[Dianne B. Elderkin]{.underline}, Woodcock Washburn LLP, of
Philadelphia, Pennsylvania, argued for defendant-appellant. With her on
the brief were [Joseph Lucci]{.underline}, [Lynn A.]{.underline}
[Malinoski]{.underline} and [Steven D. Maslowski]{.underline}.

Appealed from: United States District Court for the Northern District of
California

Judge James Ware

**United States Court of Appeals for the Federal Circuit**

03-1370

HOME DIAGNOSTICS, INC.,

Plaintiff-Appellee,

v\.

LIFESCAN, INC.,

Defendant-Appellant.

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

DECIDED: August 31, 2004

\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_

Before RADER, DYK, and PROST, [Circuit Judges]{.underline}.

RADER, [Circuit Judge]{.underline}.

The United States District Court for the Northern District of California
held that Home Diagnostics, Inc.'s (HDI's) Prestige blood glucose meters
do not infringe LifeScan, Inc.'s (LifeScan's) patent on the use of
reflectance to measure analyte concentration in a colored biological
fluid. [Home Diagnostics, Inc. v. LifeScan, Inc.]{.underline}, No.
5:01-cv-20725-JW (N.D. Cal. Oct. 2, 2002) (Claim Construc­tion Order);
[Diagnostics, Inc. v. LifeScan, Inc.]{.underline}, No. C 01-20725 JW
(PVT) (ADR) (N.D. Cal. Apr. 14, 2003) (Order Entering Judgment). Because
the district court did not give the claim language its full scope and
customary meaning, this court reverses the district court's claim
construction order, vacates the order entering judgment, and remands for
determination of validity and infringement.

I.

LifeScan's U.S. Patent No. 6,268,162 (the '162 patent) claims a method
for determining the concentration of an analyte in colored biological
fluids. '162 patent, col. 1, ll. 31-35. Thus, the claimed invention
detects the concentration of glucose in whole blood, an important
measure for diabetics. This technology facilitates both medical
diagnosis and treatment of conditions where less than a microgram per
deciliter of an analyte has clinical significance. [Id.]{.underline} at
col. 1, ll. 37-39.

Claim 4 of the '162 patent claims a method of measuring glucose
concentration in whole blood with a reflectance-reading device. The
prior art teaches a minimally automated process that requires the user
to place a drop of blood on a test strip, simultaneously start a timer,
wait a specified period of time, and then blot the test strip to remove
excess blood. Finally the prior art requires the patient to stop the
reaction between the glucose in the blood and the chemicals on the test
strip. These somewhat complex steps can cause measurement inaccuracies
that could result in improper treatment. The claimed invention relieves
the patient of timing the operation while blotting excess blood. Claim 4
of the '162 patent recites:

> A method for measuring glucose concentration in a sample of whole
> blood using a reflectance-reading device which comprises the steps of:

(a) providing a test strip for placement in the reflectance reading
    device, the test strip having a matrix pad with a sample receiving
    surface and a testing surface opposite the sample-receiving surface,
    which matrix pad further comprises a reagent for reacting with the
    glucose in the blood sample and creating a change in reflectance at
    the testing surface indicative of the glucose concentration in the
    sample;

(b) applying a sample of whole blood to the sample-receiving surface and
    allowing at least a portion of the sample to travel to the testing
    surface and react with the reagent;

(c) taking a sequence of reflectance readings from the testing surface
    of said matrix at [specified time intervals upon detecting a
    predetermined drop in reflectance sufficient to indicate that said
    sample has reached said first surface]{.underline}; and

(d) [upon detection of a suitably stable endpoint, calculating said
    glucose concentration in said sample from one of said reflectance
    readings]{.underline}, without having determined the time at which
    the sample was initially applied to the matrix pad.

[Id.]{.underline} at col. 22, l. 59 -- col. 23, l.18 (emphases added).

HDI initiated this suit by seeking a declaratory judgment that its
Prestige blood glucose meters do not infringe the '162 patent either
directly or under the doctrine of equivalents. LifeScan filed a
counterclaim for infringement. The parties dispute the meaning of four
claim terms, but the issue central to these disputes focuses on the
meaning of "upon detection of a suitably stable endpoint." LifeScan
construes this claim language to mean, "when the stated reaction between
glucose in the blood sample and reagents in the test strip is
sufficiently complete that the glucose concentration of the sample can
be calculated 'accurately,' i.e., without an error of clinical
significance." HDI construes the same language as, "at the expiration of
a predetermined time period."

After a [Markman]{.underline} hearing, the district court interpreted
claim 4 as limited to predetermined timing methods. In accordance with
this understanding, the trial court construed "suitably stable endpoint"
to mean "at the expiration of a predetermined time period." This claim
construction effectively precluded LifeScan from seeking infringement of
its '162 patent because HDI's accused infringing device does not use a
predetermined timing methodology. Instead, the accused infringing device
uses a rate methodology that monitors the rate at which the chemical
reaction between glucose from the sample and the reagent occurs. Under
the rate methodology, an endpoint is reached when the rate at which the
chemical reaction is occurring falls below a certain level. In an effort
to facilitate this appeal, LifeScan stipulated that it could not prove
infringement given the trial court's claim construction. Accordingly,
the district court entered a judgment of noninfringement for HDI and
dismissed LifeScan's infringement counterclaim. The district court's
order was rendered final under Federal Rule of Civil Procedure 54(b).
Given this sequence of events, the procedural posture of this appeal is
analogous to an appeal of summary judgment. That is, if the claim
construction is in error, this court will vacate the judgment and remand
the case for disposition on the merits.

LifeScan timely appeals. This court has jurisdiction under 28 U.S.C.
§ 1295(a)(1).

II\.

This court reviews claim construction without deference. [Cybor Corp. v.
FAS Techs., Inc.]{.underline}, 138 F.3d 1448, 1454 (Fed. Cir. 1998)
([en]{.underline} [banc]{.underline}). LifeScan's appeal focuses solely
on claim construction. At the center of the debate between the two
parties is the claimed method of stopping the measurement period, step
(d) of claim 4 of the '162 patent. LifeScan argues the district court
erred by overlooking the accepted contextual meaning of the claim term
and limiting claim 4 to a preferred embodiment which utilizes a
predetermined timing method to determine the end of the measurement
period. HDI argues that LifeScan has clearly disavowed claim scope by
disclosing only predetermined timing methods.

As always, the claim language itself governs the meaning of the claim.
[Vitronics Corp. v. Conceptronic, Inc.]{.underline}, 90 F.3d 1576, 1582
(Fed. Cir. 1996). This court construes the meaning of claim language
according to its usage and context. [ResQNet.com, Inc. v. Lansa,
Inc.]{.underline}, 346 F.3d 1374, 1378 (Fed. Cir. 2003). The touchstone
for discerning the usage of claim language is the understanding of those
terms among artisans of ordinary skill in the relevant art at the time
of invention. [See]{.underline} [Rexnord Corp. v. Laitram
Corp.]{.underline}, 274 F.3d 1336, 1342 (Fed. Cir. 2001). Indeed, normal
rules of usage create a \"heavy presumption\" that claim terms carry
their accustomed meaning in the relevant community at the relevant time.
[CCS Fitness, Inc. v. Brunswick Corp.]{.underline}, 288 F.3d 1359, 1366
(Fed. Cir. 2002) (citing [Johnson Worldwide Assocs., Inc. v. Zebco
Corp.]{.underline}, 175 F.3d 985, 989 (Fed. Cir. 1999)). The patent
applicant may also define a claim term in the specification \"in a
manner inconsistent with its ordinary meaning.\" [Boehringer Ingelheim
Vetmedica, Inc. v. Schering-Plough Corp.]{.underline}, 320 F.3d 1339,
1347 (Fed. Cir. 2003) (citing [Teleflex, Inc. v. Ficosa N. Am.
Corp.]{.underline}, 299 F.3d 1313 at 1325-26 (Fed. Cir. 2002)). In other
words, a patent applicant may define a term differently from its general
usage in the relevant community, and thus expand or limit the scope of
the term in the context of the patent claims. [Id.]{.underline}

Another tool to supply proper context for claim construction is the
prosecution history. As in the case of the specification, a patent
applicant may define a term in prosecuting a patent. [CCS
Fitness]{.underline}, 288 F.3d at 1366 (a \"claim term will not receive
its ordinary meaning if the patentee acted as his own lexicographer and
clearly set forth a definition of the disputed claim term\" in the
specification or prosecution history). This court also acknowledges the
relevance of extrinsic evidence, often presented in the form of expert
testimony. [Vitronics]{.underline}, 90 F.3d at 1585; [Pitney Bowes, Inc.
v. Hewlett-Packard Co.]{.underline}, 182 F.3d 1298, 1309 (Fed. Cir.
1999) ("\[C\]onsultation of extrinsic evidence is particularly
appropriate to ensure that \[the court's\] understanding of the
technical aspects of the patent is not entirely at variance with the
understanding of one skilled in the art."). Other useful references for
construing disputed terms include dictionary definitions and treatises.
[See, e.g.]{.underline}, [Tex. Digital Sys., Inc. v. Telegenix,
Inc.]{.underline}, 308 F.3d 1193, 1202 (Fed. Cir. 2002)
("\[D\]ictionaries, encyclopedias and treatises are particularly useful
resources to assist the court in determining the ordinary and customary
meanings of claim terms.").

As noted before, these claim construction aids inform the court's task
of ascertaining the meaning of the claim terms to one of ordinary skill
in the art at the time of invention. [Moba v. Diamond Automation,
Inc.]{.underline}, 325 F.3d 1306, 1315 (Fed. Cir. 2003) ("Moreover, as
this court has repeatedly counseled, the best indicator of claim meaning
is its usage in context as understood by one of skill in the art at the
time of invention."); [Ferguson Beauregard v. Mega Sys.,
LLC]{.underline}, 350 F.3d 1327, 1338 (Fed. Cir. 2003) ("The words used
in the claims must be considered in context and are examined through the
viewing glass of a person skilled in the art."); [Interactive Gift
Express, Inc. v. Compuserve Inc.]{.underline}, 256 F.3d 1323, 1332 (Fed.
Cir. 2001) ("\[I\]t is important to bear in mind that the viewing glass
through which the claims are construed is that of a person skilled in
the art."); [Markman v. Westview Instruments, Inc.]{.underline}, 52 F.3d
967, 986 (Fed. Cir. 1995) ([en]{.underline} [banc]{.underline})
("\[T\]he focus is on the objective test of what one of ordinary skill
in the art at the time of the invention would have understood the term
to mean.").

In this case, this court must ascertain the meaning of the claim
language "upon detection of a suitable stable endpoint." The claim
language does not explicitly require a predetermined time for the
reaction, but instead measures the endpoint by the stability of the
reflectance. Thus, according to this language, the endpoint coincides
with a suitable stability in the reflectance readings. At this stable
endpoint, the method calculates the glucose concentration. The claim
limitation emphasizes that the method does not require any determination
of a starting point for application of the blood sample to the matrix.
In sum, the claim language limits the endpoint by reference to suitable
stability in the reflectance readings, not by reference to a
predetermined time.

The specification contains further enlightenment on the accustomed usage
of "upon detection of a suitably stable endpoint" among artisans of
ordinary skill at the time of invention. In discussing the invention as
a whole, the specification states that the concentration of an analyte
in a sample: "may be determined by measuring the change . . . between
two or [more]{.underline} points in time." [Id.]{.underline} at col. 7,
ll. 57-59 (emphasis added). This language shows that a "suitably stable
endpoint" varies between unspecified points in time. A predetermined
timing method is simply one means of determining when a "suitably stable
endpoint" has been reached. In discussing a single embodiment of the
invention that used a predetermined reaction time, the '162 patent
specifically states: "\[u\]sing the preferred embodiments described
herein, the endpoint is not particularly stable and must be precisely
timed." [Id.]{.underline} at col. 14, ll. 42-44. Thus, the specification
limits its discussion of predetermined timing methods to preferred
embodiments. Nevertheless, the invention as claimed permits detection of
the endpoint with reference to the stability of the reflectance
readings.

To overcome the presumption biasing claim construction in favor of the
accustomed usage of a term in the relevant community at the relevant
time, HDI must show a clear disavowal of such scope in the
specification, prosecution history, or both. The district court erred by
placing too much emphasis on the specification's discussion of the
preferred embodiments, rather than the meaning of the claims themselves.
Because the specification discussed only predetermined timing methods,
the district court concluded incorrectly that the applicant had
disavowed other ways to reach an endpoint. The specification describes a
preferred embodiment of the '162 patent that uses a predetermined twenty
second time period for blood samples with glucose concentrations below
250 mg/dl and a predetermined thirty second time period for samples with
glucose concentrations between 250 mg/dl and 450 mg/dl. '162 patent,
col. 14, ll. 47-49. Because the specification described no other
embodiments in detail, the district court apparently interpreted the
specification's silence regarding alternative embodiments as a
disavowal. However, the applicant's choice to describe only a single
embodiment does not mean that the patent clearly and unambiguously
disavowed other embodiments. [See]{.underline} [Liebel-Flarsheim Co. v.
Medrad, Inc.]{.underline}, 358 F.3d 898, 907-08 (Fed. Cir. 2004).

As noted earlier, the specification's overall context shows that the
endpoint "may be determined by measuring the change . . . between two or
[more]{.underline} points in time." [Id.]{.underline} at col. 7, ll.
57-59 (emphasis added). The preferred embodiments that used the
predetermined timing method simply do not limit the broader claim
language. This court has previously stated that reference to a preferred
embodiment does not alone undermine the customary meaning and scope of
claim language. [Teleflex]{.underline}, 299 F.3d at 1327. The meaning of
the claim term "upon detection of a suitably stable endpoint"
encompasses multiple methods for finding the proper endpoint. The
patent's preferred embodiment is just that -- one way of using the
invention. That disclosure alone does not clearly and unambiguously
disavow other ways of computing the endpoint within the scope of the
claim language.

A patentee may claim an invention broadly and expect enforcement of the
full scope of that language absent a clear disavowal or contrary
definition in the specification. [Id.]{.underline} at 1325. The history
of the '162 patent illustrates that this applicant took this course. The
'162 patent is part of a family of patents that includes U.S. Patent
Nos. 5,049,487 (the '487 patent) and 5,843,692 (the '692 patent). These
patents stem from the same initial application and contain the same or
essentially the same specifications. In place of a "suitably stable
endpoint," the '487 patent claims recite a "predetermined time period."
'487 patent, col. 22, l. 36. Similarly, the '692 patent claims recite a
"predetermined incubation period" rather than a "suitably stable
endpoint." '692 patent, col. 23, l. 22. This progression, from
"predetermined time period" to "predetermined incubation period" to
"suitably stable endpoint," shows that LifeScan purposefully sought in
the '162 patent claim scope broader than the predetermined timing
method. Absent a clear disavowal or contrary definition in the
specification or the prosecution history, the patentee is entitled to
the full scope of its claim language.

The prior art identified by the '162 patent gives additional reasons
that an artisan of ordinary skill would not limit "upon detection of a
suitably stable endpoint" to predetermined timing methods.
[See]{.underline} [Kumar v. Ovonic Battery Co.]{.underline}, 351 F.3d
1364, 1368 (Fed. Cir. 2003); [see also]{.underline} [Arthur A. Collins,
Inc. v. N. Telecom, Ltd.]{.underline}, 216 F.3d 1042, 1045 (Fed. Cir.
2000) ("When prior art that sheds light on the meaning of a term is
cited by the patentee, it can have particular value as a guide to the
proper construction of the term, because it may indicate not only the
meaning of the term to persons skilled in the art, but also that the
patentee intended to adopt that meaning.").

Specifically, U.S. Patent Nos. 4,178,153 and 4,627,014 (the '153 patent
and the '014 patent) show the usage of the claim terms at the time of
invention. The '153 patent, entitled "Method and Apparatus for Chemical
Spot Test Analysis" relates to chemical analysis of a sample with
reagents on a fibrous or porous medium after a predetermined period of
time. '153 patent, col. 1, ll. 46-51. The '153 patent discloses both an
endpoint-seeking methodology and a predetermined-timing methodology. In
disclosing an endpoint-seeking methodology, the '153 patent states that
a sample can be analyzed, "by monitoring the resultant constituent
manifesting reaction." [Id.]{.underline} at col. 3, ll. 26-27.
Alternatively, the '153 patent discloses that the analysis can utilize,
"a single point measurement, i.e., with a single measurement of reaction
product." [Id.]{.underline} at col. 4, ll. 27-28. The '153 patent
demonstrates that as early as 1979, artisans of ordinary skill in the
art knew that a chemical analysis of a sample with reagents could be
accomplished by either monitoring the reaction itself or by using a
single measurement of the reaction product.

The '014 patent, entitled "Method and Apparatus for Determination of an
Analyte and Method of Calibrating such Apparatus," reinforces this
point. This prior art reference states that the measurement of an
analyte can utilize "any chemical analyzer constructed to perform rate
or endpoint colorimetric assays." '014 patent, col. 7, ll. 50-52.

In light of the preceding analysis, this court determines that the
customary meaning in this art field of "upon detection of a suitable
stable endpoint" means "when the stated reaction is sufficiently
complete that the glucose concentration of the sample can be calculated
without an error of clinical significance." This determination is
confirmed by using the contemporary understanding of a skilled artisan
to guide an inquiry into dictionary meanings. [Multiform Desiccants,
Inc. v. Medzam, Ltd.]{.underline}, 133 F.3d 1473, 1477 (Fed. Cir. 1998).
LifeScan offers a dictionary definition of the term "stable" as "not
subject to sudden change: subject to relatively limited fluctuations."
[Webster's Third New International Dictionary]{.underline} 2071 (3d ed.
1986). Alternatively, Webster's also defines "stable" as "firmly
established." [Id.]{.underline} The first definition conforms to the
usage of "stable" by one of ordinary skill in the art as manifested by
the pertinent prior art references identified by the '162 patent.

In contrast, the alternative dictionary definition would import an
additional limitation into the claim, namely that the analyte's reaction
product and the reagent must be firmly established.

Thus, an examination of dictionary sources guided by the prior art
references enlightens the meaning of "stable" and confirms this court's
determination that the customary meaning in this art field of "upon
detection of a suitable stable endpoint" means "when the stated reaction
is sufficiently complete that the glucose concentration of the sample
can be calculated without an error of clinical significance."

LifeScan also appeals the district court's construction of the claim
terms: a) "specified time interval"; b) "upon detecting a predetermined
drop in reflectance sufficient to indicate that sample reached said
first surface"; and c) "calculating said glucose concentration in said
sample from one of said reflectance readings." Because the district
court read those terms as limited to predetermined timing methods, those
claim terms as well require revision based on the full scope of the
claim language as understood by those of skill in the art at the time of
invention.

Specifically, the district court erred in construing "specified time
interval" to mean "times set in advance" because it limited claim 4 of
the '162 patent to a preferred embodiment. Claim Construction Order at
5. Again consulting dictionaries within the context of this field of
technology at the time of invention, "interval" is "a space of time
between two events or points of time." [Webster's Third New
International Dictionary]{.underline} at 1183. This definition does not
carry any hint of predetermined time calculations or intervals. Because
LifeScan does not clearly disavow this customary meaning of the claim
term, "specified time interval" means "a space of time between two
events." In this instance, the interval refers to the space of time
between reflectance readings from the testing surface of the matrix.

The district court construed "upon detecting a predetermined drop in
reflectance sufficient to indicate that sample reached said first
surface" to mean:

> \[A\] reflectance reading taken immediately following or very soon
> after detecting the point in time of a drop in reflectance, the
> magnitude of which is determined in advance, [to be the point in time
> of the first breakthrough of sample to the testing
> surface]{.underline}. At that point in time, the reflectance drop must
> be mostly or entirely due to wetting of the testing surface and not
> color from chemical reaction.
>
> Claim Construction Order at 5 (emphasis added). In sum, the district
> court strictly limited the claim term to the "first breakthrough of
> sample to the testing surface." Because the district court restricted
> claim 4 of the '162 patent to predetermined timing methods, it limited
> the initiation of the measuring phase to "the [first]{.underline}
> breakthrough." As discussed previously, this interpretation improperly
> limits claim 4 to a preferred embodiment and does not give the
> disputed claim terms their proper scope in this technology at the time
> of invention. Therefore, "upon detecting a predetermined drop in
> reflectance sufficient to indicate that sample reached said first
> surface" means "immediately following or very soon after detecting the
> point in time of a predetermined drop in reflectance, where the
> predetermined drop in reflectance is mostly or entirely due to wetting
> of the testing surface."
>
> The district court also construed "calculating said glucose
> concentration in said sample from one of said reflectance readings" to
> mean "calculating the amount of glucose contained per unit volume in
> the sample from the reflectance reading taken at the expiration of the
> [predetermined time period]{.underline}." Claim Construction Order at
> 5 (emphasis added). This construction again improperly limited claim 4
> of the '162 patent to predetermined timing methods. This court
> construes "calculating said glucose concentration in said sample from
> one of said reflectance readings" to mean "calculating the amount of
> glucose contained per unit volume in the sample using a reflectance
> reading taken when the reaction between glucose in the blood sample
> and the reagents in the test strip has reached a suitably stable
> endpoint."

III\.

This court reverses the district court's claim construction order,
vacates the order entering judgment, and remands the case for a
determination of validity and infringement.

COSTS

Each party shall bear its own costs.

# REVERSED-IN-PART, VACATED-IN-PART, and REMANDED