MOUONTAGAAA
`
`US 2012010893141
`
`ao) United States
`2) Patent Application Publication co) Pub. No.: US 2012/0108931 Al
`Taubet al.
`(43) Pub. Date:
`May3, 2012
`
`(54) CALIBRATION OF ANALYTE
`MEASUREMENTSYSTEM
`
`(75)
`
`Inventors:
`
`Mare Barry Taub, MountainView,
`CA (US); Wesley Scott Harper,
`Alameda, CA (US): Glenn Howard
`Berman, Alameda, CA (US): Jean
`Mei Huang, San Francisco, CA
`(US)
`
`(73) Assignee:
`
`Abbott Diabetes Care Inc.,
`Alameda, CA (US)
`
`(22)
`
`Filed:
`
`Jun. 29, 2011
`on
`ay
`Related U.S. Application Data
`
`(60)
`
`Provisional application No, 61/359.774, filed on Jun.
`29,2010.
`
`Publication Classification
`
`(51)
`
`Int. Cl.
`(2006.01)
`AGIB 5/1495
`(2006.01)
`AGIB 5/1468
`SZ) US GTi
`ssesceeesgenssnsiseassrovocseserizeseye, OOO/RET; GOWS45
`62)
`(57)
`
`ABSTRACT
`
`(21) Appl. No.:
`
`13/172.823
`
`
`
`A method of calibrating an analyte measurement systemis
`provided.
`
`
`
`Page | of 34
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`

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`Patent Application Publication
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`May3, 2012
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`Sheet 1 of 17
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`US 2012/0108931 Al
`
`SENSOR
`UNIT
`
`DATA
`PROCESSING
`UNIT
`
`UNIT
`
`PRIMARY
`RECEIVER
`UNIT
`
`DATA
`PROCESSING
`TERMINAL
`
`SECONDARY
`RECEIVER
`
`FIG. 1
`
`Page 2 of 34
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`Patent Application Publication
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`May 3, 2012 Sheet 2 of 17
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`FIG,2
`
`
`215
`
`Page 3 of 34
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`

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`Patent Application Publication
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`May 3, 2012 Sheet 3 of 17
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`US 2012/0108931 Al
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`Sensor
`
`FIG. 3
`
`Page 4 of 34
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`

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`Patent Application Publication
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`May 3, 2012 Sheet 4 of 17
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`US 2012/0108931 Al
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`Perfonn
`Reference|~~ —‘410
`Measurement
`
`Perform System
`Measurement
`
`420)
`
`Parameters
`
`Determine
`
`Calibration
`
`|——~ 430
`
`FIG. 4
`
`Page 5 of 34
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`Patent Application Publication
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`May 3, 2012 Sheet 5 of 17
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`US 2012/0108931 Al
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` Measure
`
`Sensor
`
`
`Current
`
`
`
`—__510
` Adjust for
`
` 530
`
`
`Compensation
`Compensation 550
`
`Processing Unit
`Specific
`Parameters
`
`Temperature
`
`ar
`
` Lag Time
`
`
`
`
`Calculate
`Sensitivity
`
`
`
`FIG. 5
`
`Page 6 of 34
`
`

`

` Scheduled or userinitiated calibration
`
`
`
`Perform Calibration Preconditions
`Check
`
`
`
`
`
`pasa
`
`Perlorm Calibration Atempt
`
`Pertorm Calibration Post Condition Check
`
`630
`
`eg
`
`
`Patent Application Publication
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`May3, 2012 Sheet 6 of 17
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`US 2012/0108931 Al
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`610
`
`620
`
`
`
`RequestCalibration Attempt
`
`Compute Real-Time Immediate
`Sensitivity
`
`640
`
`—
`
`|
`Run ESA FS Tests
`
`
`Perform Calibration Sensitivity
`Check
`
`650
`
`660
`
`670
`
`| Compute Composite Sensitivity
`
`|
`Update Composite Sensitivity
`| 690
`
`Compute Pseudo-Retrospective
`Immediate Sensitivity
`
`— 680
`
`FIG.6
`
`Page 7 of 34
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`Patent Application Publication
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`May 3, 2012 Sheet 7 of 17
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`START
`
`Perform
`Reference | 710
`Measurement
`
`Apply Specified
`Time Separation
`
`720
`
`—— 740
`
`Perform Test|——~ 730
`Measurement
`
`Determine
`Calibration
`Adjustment
`
`FIG. 7
`
`Page 8 of 34
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`Patent Application Publication
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`May 3, 2012 Sheet 8 of 17
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`PromptUser for a
`Reference Test
`
`User Performs
`Reference Test
`
`820
`
`
`
`Reference
`Test
`Accepted?
`
`
`
`Prompt Userto
`Perform On-Demand
`
`
`
`Test Measurement
`
` START
`810
`
`
`
` ____860
`
`User Performs On-
`
`
`Demand Test
`
`Measurement
`
`—_ 850
`
`
`Generate New
`
`
`Sensitivity Factor
`
`To FIG, 8B
`
`FIG. 8A
`
`Page 9 of 34
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`Patent Application Publication
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`May3, 2012 Sheet 9 of 17
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`
`
`From FIG. 8A
`
`
`
`
`
`Wait Predetermined
`Time
`
`
`
`870
`
`
`
`
`
`Prompt Userto
`Perform Another
`On-DemandTest
`Measurement
`
`S80
`
`
`
`Updated
`Sensitivity
`
`
`Factor
`
`
`890
`
`FIG. 8B
`
`Page 10 of 34
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`Patent Application Publication
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`May 3, 2012 Sheet 10 of 17
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`Imposing a First Restriction on
`
`
`START
`
`
`Calibration
`
`Imposing a Second Restriction on
`Calibration
`
`910
`
`zal
`
`930
`
`>
`
`
`
`Imposing a Third Restriction on
`Calibration
`
`
`FIG.9
`
`Page 11 of 34
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`Patent Application Publication
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`May3, 2012 Sheet 11 of 17
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`(Cal)1 =0 1020
`
`
` Begin (TE)1
` (Cal)1 > (Cal)1
`
`max?
`
`(Calj2 > (Cal)2
`
`(Cal)2 =(Cal)2 + 1
`
`
`
`
`
`Do NotAllow
`Allow Calibration
`Calibration Request
`
`
`Request
`
`
`
`
`
` FIG. 10
`
`Page 12 of 34
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`Patent Application Publication
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`May 3, 2012 Sheet 12 of 17
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`START
`
`1110
`
`Allow User to Set
`Tnocal 1
`
`1120
`
`:
`
`Allow User to Set
`Tnocal 2
`
`YES
`
`Tnocali < T <
`Tnocal2?
`
`
`
`
`Request
`
`Do Not Allow
`Calibration Request
`
`Aljlow Calibration
`
`1150
`
`FIG. 11
`
`Page 13 of 34
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`Patent Application Publication
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`May 3, 2012 Sheet 13 of 17
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`Detect Condition
`
`Condition
`Exists?
`
`
`
`
`
`1230.
`
`1240
` Do Not Allow
`Calibration
`Allow Calibration
`
`
`FIG. 12
`
`Page 14 of 34
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`Patent Application Publication
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`May 3, 2012 Sheet 14 of 17
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`Providing User Option Of Setting Date
`
`
`START
`
`
`
`And Time For Calibration
`Of Day For Calibration
` Providing User Option Of Setting Time
`
`
`1310
`
`1320
`
`FIG. 13
`
`Page 15 of 34
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`Patent Application Publication
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`May 3, 2012 Sheet 15 of 17
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`START
`
`1410
`
`1420
`
`1430 .
`
`1440
`
`1450
`
`1460
`
`Determining when the system will
`acceptcalibration
`
`Determininglikelihood calibration will
`
`succeed
`
`that a calibration will succeed.
`
`Notifying the User that the system will
`acceptcalibration
`
`Notifying the Userwith thelikelihood
`
`Providing the User With The Option to
`
`Schedule Calibration
`Scheduling calibration
`
`FIG. 14
`
`Page 16 of 34
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`Patent Application Publication
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`May 3, 2012 Sheet 16 of 17
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`START
`
`
`
`
`
`1510
`
`Set Tcal
`
`T(cal) window
`< T < T(cal)?
`
`
`
`
`
` Allow Calibration
`
`
`
`Calibration
`
`Do Not Allow
`
`1550-
`
`FIG, 15
`
`Page 17 of 34
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`Patent Application Publication
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`May 3, 2012 Sheet 17 of 17
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`START
`
`1610_ 7 Detect Condition
`
`
`
`
`1620
`
`Condition
`Exists?
`
`
` Do Not Allow
`Calibration
`
`
`
`Altow Calibration
`
`FIG. 16
`
`Page 18 of 34
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`US 2012/0108931 Al
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`May3, 2012
`
`CALIBRATION OF ANALYTE
`MEASUREMENT SYSTEM
`
`RELATED APPLICATION
`
`[9001] he present application claims the benefit of U.S.
`Provisional Application No. 61/359,774 filed Jun. 29, 2010
`entitled “Calibration of Analyte Measurement System,” the
`disclosure of whichis incorporated herein byreferenceforall
`purposes.
`
`BACKGROUND
`
`[0002] Monitoring ofthe level of glucose orother analytes,
`such as lactate or oxygen, in certain individuals is vitally
`important to their health. High or lowlevels of glucose or
`other analytes may have detrimental effects. Monitoring of
`glucoseis particularly important to individuals with diabetes.
`Diabetics may need to monitor glucose levels to determine
`wheninsulin is needed to reduce glucose levels in their bodies
`or when additional glucose is needed toraise the level of
`glucose in their bodies. In non-diabetic individuals, it may be
`important
`to monitor glycemic responses to determine
`whether therapeutic approaches may be useful to prevent the
`onset ofdiabetes.
`[0003] Analyte monitoring systems may be designed to test
`blood samples taken periodically and measured outside ofthe
`body (in vitro testing), such as by putting a drop ofbload on
`a lest strip, and performing an analyte analysis onthe test
`strip. Blood may be taken from a finger (by performing a
`“fingerstick”) or other locations onthe body, such as the arm,
`thigh, etc. Tests performed in such a manner maybe referred
`to as “discrete” measurements, and in the case of glucose
`measurements, “blood glucose” (BG) measurements. Other
`systems are designed to measure analyte levels within the
`body(in vivo), using a suitable sensor, without drawing blood
`for every measurement. Certain systems have combined func-
`tionality for performing both sensor-basedas well as discrete
`measurements.
`
`Insomesituations, it is medically desirable to moni-
`[0004]
`tor analyte levels in a subject closely, over a substantial period
`of time, or on an ongoingbasis for an extended timeperiod,in
`somecases indefinitely.A monitor that tracks glucose levels
`by automatically taking periodic in vivo measurements, €.2..
`one measurement per minute, or moreor less frequently, is
`known as a “continuous glucose monitor” (CGM). Priorart
`CGMshave been provided, for example, in the form of a
`system. A portion ofthe system, comprising an electrochemi-
`cal sensor partially inserted into the skin. and an associated
`processor and transmitter, with a self-contained power sup-
`ply, is attached to the body ofthe user and will remain in place
`for an extended period ofhours, days, weeks, etc, The trans-
`mitter takes analyte measurements periodically and transmits
`them, for example, by short-range radio communications,to
`a separate receiver/display device. The receiver/display
`device will typically receive discrete BG measurements(e.2.,
`from a separate BG meteror an included BGtest strip port),
`as well as a port, such as a USBport, for communications with
`upstream computers and/or other electronics.
`In some
`embodiments, the receiver unit may be directly or indirectly
`interfaced with an insulin pump. for managing the subject's
`insulin therapy
`[0005] The accuracy ofthe analyte measurements obtained
`with an in vivo sensing system is important. Calibration of
`such systems may be performed by comparingin vivo “sys-
`
`tem” measurements against discrete BG “reference mea-
`surements from fingerstick samples measured on a test strip.
`[0006] CGM systemstypically perform calibrations on a
`fixed schedule. However, such a fixed schedule may impose
`inconvenience on the user if a required calibration occurs
`when a user is occupied with otheractivities or asleep. In
`some instances a required calibration may occur when ana-
`lyte levels are in a state ofinstability or rapid change. Cali-
`brations taken during such times of unstable analyte levels
`may sometimes provide less than optimal results, Accord-
`ingly,
`it would be desirable to provide calibration routines
`whichallow customizationbyuser. It would also be desirable
`to provide calibration routines whichcalibrate when the ana-
`lyte levels and rates ofchange are more desirable for accurate
`measurement and observation.
`
`SUMMARY
`
`(0007) An analyte measurement system and a method for
`calibrating a signal from an electrochemical sensor are pro-
`vided. A signal is generated from the sensor, which corre-
`sponds to an analyte concentration level in a biofluid of a
`subject. A user interface prompts auser to assay a calibration
`sample of the user’s blood to obtain a calibration valueif a
`first condition is met. A processoris configured to correlate
`ihe calibration value to at least one of the signals from the
`sensorif the first condition of is met.
`
`In some embodiments the method further includes
`[0008]
`selecting a first
`time frame. In some embodiments,
`the
`method includes selecting amaximum numberofcalibrations
`in thefirst time frame. Thefirstcondition may be met if fewer
`than the maximumnumberofcalibrations has occurred in the
`first time frame.
`
`In some embodiments the method further includes
`[0009]
`selecting a second time frame. The method may include
`selecting @ maximum numberofcalibrations in the second
`time frame. Thefirst condition may be met iffewer than the
`maximum numberofcalibrations has occurred in the second
`time frame.
`
`In some embodiments, the method further includes
`(0010]
`prompting the userto assay a calibration sample of the user’s
`blood to obtain a calibration value if a second condition is
`met. The method may further include allowing the user to
`select a time period in which calibrations are not accepted.
`The second condition may be met if the current timeis outside
`the selected time period.
`{0011}
`In some embodiments, the system further includes
`prompting the userto assay a calibration sample ofthe user’s
`blood to obtaina calibration value,ifa third condition is met.
`The method may include determining the existence ofa con-
`dition relating the subject. In some embodiments, the condi-
`tion comprises a determination of whether the subject is
`asleep. The third condition maybe metif the condition does
`not exist. In some embodiments, the analyte is glucose.
`[0012]
`In some embodiments.
`the assayed calibration
`sample is obtained from a fingerstick testing site. In some
`embodiments,
`the assayed calibration sample is obtained
`from an alternative site test. The location of the assayed
`calibration sample maybetheleg of'a user, or the abdomen of
`a user, Obtaining the calibration measurement may include
`determining the calibration measurementin less than or equal
`to about 1 wL of blood. In some embodiments, the calibration
`value is compared toat least onesignal from the sensorfor use
`in calibrating the sensor.
`
`Page 19 of 34
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`

`US 2012/0108931 Al
`
`May3, 2012
`
`duration ofsensor operation and determiningstability ofthe
`sensor signal at a reference durationof sensor operation. A
`calibration may be requested if the stability of the sensor
`signal at the reference duration of sensoroperationis below a
`threshold. The reference duration of sensor operation may
`refer to an elapsed time following insertion ofthe sensor in
`the subject. In some embodiments, the reference duration
`comprises four hours.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`
`[0013] An analyte measurement system and a method for
`calibrating a signal from an electrochemical sensoris pro-
`vided, which includes generating a signal from the sensor, the
`signal corresponding to an analyte concentration level in a
`biofluid ofa subject; providing a user the optionto select a
`time for obtaining a calibration sample ofthe user’s blood to
`obtain a calibration value; and correlating the calibration
`value to at least one ofthe signals from the sensor if the
`current time corresponds to the selected time.
`[0014]
`Insome embodiments, the method includes provid-
`ing auser an optionto select a time comprises providing a user
`the option to select a date and a time for calibration. The
`method may include providing a user an option to select a
`time comprises providing a user the optionto select a time for
`recurrentdailycalibration. In some embodiments, the analyte
`is glucose.
`[0015] An analyte measurement system and a method for
`calibrating a signal from an electrochemical sensor is pro-
`vided which includes generating a signal from thesensor, the
`signal corresponding to an analyte concentration level in a
`biofluid of a subject; determining whether calibration is
`accepted; and providing a user the option to obtain a calibra-
`tion sample ofthe user’s blood to obtain a calibration value if
`calibration is accepted: and correlating the calibration value
`to at least one of the signals from the sensor.
`[0016]
`In some embodiments, the predetermined time is
`fifteen minutes.
`In some embediments, calibration is
`accepted ifthe rate ofchange of the signal is within a prede-
`termined threshold. The method mayfurther include deter-
`mining the likelihood of successful calibration,
`In some
`embodiments,an icon is provided in a display unit relating to
`the likelihood of successful calibration.
`
`[0023] A detailed description of various aspects, features.
`and embodiments of the subject matter described herein is
`provided with reference to the accompanying drawings,
`whichare briefly described below. The drawingsare illustra-
`tive and are not necessarily drawnto scale, with some com-
`ponents and features being exaggerated for clarity. The draw-
`ings illustrate various aspects and features of the present
`subject matter and mayillustrate one or more embodiment(s)
`or example(s) of the present subject matter in wholeorin part.
`Like reference numerals used in different figures denote like
`components or process steps. Reference numerals that differ
`only in the hundreds or thousands place from reference
`numeralsin earlier figures refer (unless the context requires
`otherwise) to components or process steps that may be
`adapted fromthe corresponding component or processstep in
`the prior Figure.
`[0024]
`FIG-1 is a block diagram ofthe components of an
`analyte monitoring system in accordance with one embodi-
`meantofthe present disclosure:
`[0025]
`FIG. 2 is a schematicillustration of the components
`of an analyte monitoring system in accordance with one
`embodiment of the present disclosure;
`(0017] An analyte measurement system and a method for
`calibrating a signal from an electrochemical sensoris pro-
`
`[0026] FIG.3is a block diagram of an on-demand analyte
`vided whichincludes generating a signal from the sensor, the
`monitoring systemin accordance with one embodimentofthe
`signal corresponding to an analyte concentration level in a
`present disclosure;
`biofluid ofa subject; determining a predetermined calibration
`[0027]
`FIG. 4 is a flowchart showing,at a high level. the
`time: determining a prospective calibration window running
`flow of calibration processing in certain embodiments;
`prior to the predetermined calibration time; and allowing
`[0028] FIG.5isa flowchart further showing,ata highlevel,
`calibration if a reference analyie measurementis available
`the flowof calibration processing in certain embodiments;
`during the prospective calibration window.
`[0029]
`FIG. 6 is a flowchart showing in greater detail a
`[0018]
`Insome embodiments, the method includes provid-
`sequence ofsteps that may be performed in certain embodi-
`ing a grace period after the predetermined calibration time.
`meats in connection with calibration:
`and providing an alarmif nocalibration is performed during
`[0030] FIG.7is a Nowchart illustrating a method for cali-
`
`the time period beginning with the predetermined calibration
`brating an on-demandanalyte monitor;
`time and ending with the expiration of the grace period. In
`[0031]
`FIGS. 8A-8B is a flowchart illustrating a further
`some embodiments, the alarm is suppressed if a reference
`calibration steps that may be performed in an on-demand
`analyte measurementis available during the prospective cali-
`analyte monitor;
`bration window.
`[0032] FIG.9is a owchart illustrating calibration steps in
`
`[0019]
`Insome embodiments,the useris notified ifa refer-
`an analyte monitor in accordance with one embodimentofthe
`ence analyte measurementis being accepted for calibration.
`present disclosure;
`[0020]
`In some embodiments, the prospective calibration
`|0033] FIG.10isa flowchart illustrating calibration steps in
`window comprises a time period of 10 minutes, 30 minutes
`an analyte monitor in accordance with an embodiment of
`prior, orone hourpriorto the predetermined calibration time.
`FIG.3 ofthe present disclosure:
`[0021] An analyte measurement system and a method for
`[0034] FIG.11isa flowchart illustrating calibration steps in
`calibrating a signal from an electrochemical sensor is pro-
`an analyte monitor in accordance with an embodiment of
`vided which includes generating a signal fromthe sensor, the
`FIG. 3 ofthe present disclosure;
`signal corresponding to an analyte concentration level in a
`[0035] FIG.12isa flowchart illustrating calibrationsteps in
`biofluid ofa subject: determining a conditionrelating to the
`an analyte monitor in accordance with an embodiment of
`stability of the sensorsignal; and allowing calibrationif the
`FIG, 3 ofthe present disclosure:
`sensor stability is within a predetermined threshold.
`[0022]
`Insome embodiments, the predetermined threshold
`[0036] FIG.13 isa flowchart illustrating calibration steps in
`comprises a sensorstability of about 1 mg/dL/min. In some
`ananalyte monitor in accordance with one embodiment ofthe
`presentdisclosure;
`embodiments, the method further includes determining the
`
`Page 20 of 34
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`

`US 2012/0108931 Al
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`May3, 2012
`
`FIG. 14 isa flowchart illustrating calibration steps in
`[0037]
`ananalyte monitorin accordance with one embodimentof the
`present disclosure:
`[0038]
`FIG. 15 isa flowchartillustrating calibration stepsin
`an analyte monitorin accordance with one embodiment ofthe
`present disclosure: and
`[0039]
`FIG. 16 isa flowchart illustrating calibration stepsin
`an analyte monitorin accordance with one embodiment ofthe
`presentdisclosure.
`
`DETAILED DESCRIPTION
`
`[0046] Nothing contained in the Abstract or the Summary
`should be understood as limiting the scope ofthe disclosure.
`The Abstract and the Summary are provided for bibliographic
`and convenience purposes and dueto their formats and pur-
`poses should not be considered comprehensive.
`[0047] As will be apparent to thoseofskill in the art upon
`reading this disclosure, each ofthe individual embodiments
`described andillustrated herein has discrete components and
`features which may be readily separated from or combined
`with the features of any of the other several embodiments
`without departing from the scope or spirit of the present
`disclosed subject matter. Any recited method can be carried
`out in the order of events recited, or in any other order which
`is logically possible, Reference to a singular item, includes
`the possibility that there are plural of the same item present.
`When two or more items (for example, elements or processes)
`are referenced by an alternative “or”, this indicates that either
`could be present separately or any combination ofthem could
`be present together except where the presence of one neces-
`sarily excludes the other or others.
`{0048} Certain classes of analyte monitors are provided in
`small, lightweight, battery-powered and electronically-con-
`trolled systems. Such a system maybe configured to detect
`signals indicative ofin vivo analyte levels using an electro-
`chemical sensor, and to process and/or collect such signals.In
`some embodiments, the portion ofthe system that performs
`this initial processing may be configured to transmit the ini-
`tially processed data to another unit for further collection
`and/or processing. Such transmission may be effected, for
`example, via a wired connection, suchaselectrical contacts or
`a cable, or via a Wireless connection, such as an IR or RF
`connection.
`
`[0040] A detailed description ofthe disclosure is provided
`herein. It should be understood, in connection with the fol-
`lowing description, that the subject matter is not limited to
`particular embodiments described, as the particular embodi-
`ments of the subject matter may ofcoursevary. It is also to be
`understoodthat the terminology used herein is forthe purpose
`of describing particular embodiments only, and is not
`intended to be limiting. since the scope of the disclosed sub-
`ject matter will be limited only by the appended claims.
`[0041] Where a rangeofvaluesis provided,it is understood
`that eachintervening value between the upper and lowerlimit
`ofthat range and any other stated or intervening value in that
`stated range,
`is encompassed within the disclosed subject
`matter. Every range stated is also intended to specifically
`disclose each and every “sub range”of the stated range. That
`is, each and every range smaller than the outside range speci-
`fied by the outside upperand outside lower limits given fora
`range, whose upperand lowerlimitsare withinthe range from
`said outside lowerlimit to said outside upperlimit (unless the
`context clearly dictates otherwise), is also to be understood as
`encompassed within the disclosed subject matter, subject to
`(0049] Certain analyte monitoring systemsfor in vivo mea-
`any specifically excluded range or limit within the stated
`surement employ a sensor that measures analyte levels in
`range. Wherearangeis stated byspecifying one or both ofan
`interstitial fluids under the surface of the subject’s skin. In
`upper and lowerlimit. ranges excludingeither or bothofthose
`certain embodiments, a sensor may be inserted transcutane-
`stated limits, or including one or both of them, are also
`ously or subcutaneously (i.e., at least partially through the
`encompassed within the disclosed subject matter, regardless
`skin), or in other embodiments, may be inserted entirely or
`of whether or not words such as “from”, “to”, “through”, or
`wholly implanted belowthe skin. A sensor in such a system
`“including”are or are not used in describing the range.
`may operate as an electrochemical cell. Such a sensor may
`[0042] Unless defined otherwise. all technical and scien-
`use any of a variety of electrode configurations, such as a
`three-electrode configuration (e.g, with “working”, “refer-
`tific terms used herein have the same meaning as commonly
`understood byone of ordinary skill in the art to which this
`ence” and “counter” electrodes), driven by a controlled
`disclosed subject matter belongs. Although any methods and
`potential (potentiostat) analog circuit, a two-electrode system
`materials similar or equivalent to those described herein can
`configuration (e.., with only working and counter elec-
`also beused in the practiceor testing of the present disclosed
`trodes), which may be self-biasing and/orself-powered, and/
`subject matter, this disclosure may specifically mention cer-
`or other configurations.
`tain exemplary methods and materials.
`[0050]
`Incertain systems, the analyte sensoris in commu-
`[0043] All publications mentioned in this disclosure are,
`nication with a data processing/transmitter unit; the term
`“transmitter unit” or “transmitter device”as usedin this dis-
`unless otherwise specified, incorporated herein by reference
`for all purposes, including without limitation to disclose and
`closure sometimes refers to such a combinationofan analyte
`describe the methods and/or materials in connection with
`sensor with such a data processing/transmitter unit. Certain
`whichthe publications are cited.
`embodiments are modular. The transmitter device may be
`separately provided as a physically distinct assembly, and
`[0044] The publications discussed herein are provided
`configured to transmit the analyte levels detected by the sen-
`solely for their disclosure priorto the filing date of the present
`sor over a communication link to a receiver/monitor unit.
`application. Nothing herein is to be construed as an admission
`referred to in this disclosure as a “receiver unit” or “receiver
`that the present disclosed subject matter is not entitled to
`device”, or in some contexts, depending on the usage, as a
`antedate such publication by virtue ofprior invention. Pur-
`“display unit,” “handheld unit,” or “meter”.
`ther, the dates of publication provided may be different from
`the actual publication dates. which may need to be indepen-
`[0051] The receiver unit may performdata analysis. ete. on
`dently confirmed.
`the received analyte data to generate information pertaining
`[0045] As used herein and in the appended claims, the
`to the monitored analyte levels. The receiver unit may incor-
`singular forms “a”, “an”, and “the” include plural referents
`porate a display screen, which can be used, for example, to
`unless the context clearly dictates otherwise.
`display measured analyte levels. It is also useful for a user of
`Page 21 of 34
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`

`US 2012/0108931 Al
`
`May3, 2012
`
`an analyte monitor to be able to see trend indications (includ-
`ing the magnitude and direction of any ongoing trend), and
`such data may be displayed as well, eithernumerically, or by
`a visual indicator, such as an arrow that may vary in visual
`attributes, such as size, shape, color, animation, or direction.
`The receiver device may further incorporate a test strip port
`and related electronics in order to be able to make discrete
`(¢.g., BG) measurements,
`{0052] The modularity of these systems may vary. In some
`embodimentsthe sensoris attachable and detachable fromthe
`transmitter (and transmitter reusable), while in other embodi-
`ments, the sensor and transmitter may be provided as an
`integrated package, which may be disposable.
`[0053] To provide flexibility in analyte sensor manufactur-
`ing anWor design,
`it may be desirable for the transmitter
`device to accommodate a substantial range of analyte sensor
`sensitivities. Methods and systems for measuring sensor sen-
`sitivity are desirable in such cases, so that the analyte monitor
`maybe accurately calibrated.
`[0054]
`FIG. 1 shows one embodiment of an analyte mea-
`surement system 100. In sucha system,a data processing unit
`or sensor control unit 120 may interact with an analyte sensor
`110 to obtain signals representative of analyte levels. Data
`processing unit 120 may further include a communications
`circuit with associated electronics (not shown),
`In some
`embodiments, the data processing unit 120 and sensor 110 are
`disposed on the body ofthe subject. Accordingly, the data
`processing uni! 120 and the sensor 110 may be referred to
`collectively herein as an “on-body unit” 101, A receiver unit
`or monitor unit 140 mayalso be provided. In the embodiment
`shown, data processing unit 120 and receiver unit 140 com-
`municate via connection 130 (which in certain embodiments
`may be a wireless RF connection). In some embodiments, a
`secondary monitor unit 160 may be provided. A data process-
`ing termina] 150 may provide further processing or review of
`analyte data.
`[0055]
`In certain embodiments, system 100 may be a con-
`tinuous glucose monitoring (CGM) system, and accordingly
`operate in a made in which the communications via connec-
`tion 130 has sufficient range to support a flow ofdata from
`on-body unit 101 to monitor unit 140. In some embodiments,
`the data flow ina CGM system is automatically provided by
`the on-body unit 101 to the monitor unit 140. For example, no
`user interveation may be required for the on-bodyunit 101 to
`send the data to the monitor unit 140. In some embodiments,
`the on-bodyunit 101 provides the signal relating to analyte
`level to the monitor unit 140 ona periodic basis. For example.
`the signal may be provided, e,g., automatically sent, on a fixed
`schedule, e.g., once every 250 ms. once a second, once a
`minute, etc. In some embodiments, the signal is provided to
`the monitor unit 140 upon the occurrence ofan event, e.g. a
`hyperglycemic event or a hypoglycemic event, etc. In some
`embodiments, data processing unit 120 may further include
`local memory in which it may record “logged data”or buff-
`ered data collected overa period oftime and provide the some
`or all of the accumulated data to monitor unit 140 periodi-
`cally. In other embodiments,a separate data logging unit may
`be provided to acquire periodically transmitted data from
`transmitter device 120, Data transmission in a CGM system
`may be one-way communication, e.g., the on-body unit 101
`provides data to the monitor unit 140 without receiving sig-
`nals from the monitor unit 140. In some embodiments, two-
`way communication is provided between the on-body unit
`101 and the monitor unit 140.
`
`In some embodiments, a signal is provided to the
`[0056]
`monitor unit 140 “on demand.” According to such embodi-
`meuts, the monitor unit 140 requests a signal from the on-
`body unit 101, or the on-body unit 101 maybe activated to
`send signal uponactivationto do so. Accordingly, one or both
`of the on-body unit 101 and monitor unit 140 may include a
`switch activalable by a user or activated upon same other
`action or event, the activationofwhich causes analyte-related
`signals to be transferred ftom the on-body unit 101 to the
`monitor unit 140. For example, the monitor unit 140 is placed
`in close proximity with a transmitter device and initiates a
`data transfer, either over a wired connection,or wirelessly by
`various means, including, for example, various RF-carried
`encodings and protocols, such as radio frequency identifica-
`tion (RFID)protocols, and IR links.
`[0057]
`Insome embodiments, the signalrelating to analyte
`level is instantaneously generated by the analyte sensor 110
`upon receipt ofthe request, and transmitted to the monitor
`unit 140 as requested, and/or the signal relating to analyte
`level is periodically obtained, e.g., once every 250 ms, once a
`second, once a minute, ete. Upon receipt of the “on demand”
`request at the on-body unit 101, an analyte signal is provided
`to the monitor unit. In somecases, the signal provided to the
`monitor unit 140 includes the most recent analyte signal(s).
`[0058]
`In further embodiments, additional data is provided
`to the monitor unit 140 “on demand.” For example, analyte
`trend data may be provided. Suchtrend data may include two
`or more analyte data points to indicate that analyte levels are
`rising, falling. or stable. Analyte trend data may include data
`from longer periods of time, such as, e.g.. several minutes.
`several hours, several days, or several weeks.
`[0059]
`Further details regarding CGM and on demand sys-
`tems are disclosed in, for example, U.S. Pat. No. 7,620,438,
`U.S. Patent Publication Nos. 2009/0054749 Al, published
`Feb. 26, 2009; 2007/0149873 Al, published Jun. 28, 2007;
`2008/0064937 Al. published Mar. 13, 2008; 2008/0071 157
`Al, published Mar. 20, 2008; 2008/0071158 Al, published
`Mar. 20, 2008; 2009/0281406 Al, published Nov. 12, 2009;
`2008/0058625 Al, published Mar. 6, 2008; 2009/0294277
`Al, published Dec. 3, 2009; 2008/0319295 Al, published
`Dec. 25, 2008; 2008/0319296 Al. published Dec. 25. 2008:
`2009/0257911 Al, published Oct. 15, 2009, 2008/0179187
`Al, published Jul. 31, 2008; 2007/0149875 Al, published
`Jun. 28, 2007: 2009/0018425 Al, published Jan. 15, 2009;
`and pending U.S. patent application Ser. Nos. 1