# US 8,788,008 B2 · System and methods for processing analyte sensor data

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- Number: US 8,788,008 B2
- Document ID: US8788008B2
- Status: Granted
- Kind: B2
- Application number: 13/149,005
- Filed: 2011-05-31
- Published: 2011-09-22
- Granted: 2014-07-22
- Earliest claimed: 2003-08-01
- Assignees: DexCom, Inc.
- Applicants: Paul V. Goode, Jr.; James H. Brauker; Apurv U. Kamath; James P. Thrower
- Inventors: Paul V. Goode, Jr.; James H. Brauker; Apurv U. Kamath; James P. Thrower
- Web page: https://patentgrep.com/patent/US8788008B2

## CPC

- A61B 5/1433: {provided with locking means (details of syringes A61M5/315)}
- A61B 3/10: Objective types, i.e. instruments for examining the eyes independent of the patients' perceptions or reactions
- A61B 5/0031: {Implanted circuitry}
- A61B 5/14532: {for measuring glucose, e.g. by tissue impedance measurement}
- A61B 5/14546: {for measuring analytes not otherwise provided for, e.g. ions, cytochromes}
- A61B 5/1468: using chemical or electrochemical methods, e.g. by polarographic means
- A61B 5/14865: {invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors}
- A61B 5/1495: Calibrating or testing of in-vivo probes
- A61B 5/4839: {combined with drug delivery}
- A61B 5/1473: invasive, e.g. introduced into the body by a catheter
- A61B 5/150022: {for capillary blood or interstitial fluid}
- A61B 5/743: {Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots}
- A61B 2560/0223: of calibration, e.g. protocols for calibrating sensors
- A61B 2560/04: Constructional details of apparatus
- A61B 2562/085: combined with means for recording calibration data
- G01N 33/48707: {by electrical means (G01N33/49, G01N33/493 take precedence)}
- Y02A 90/10: Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation
- A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D)
- G01N: INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES (measuring or testing apparatus or processes other than immunoassay, involving enzymes or microorganisms C12M, C12Q)
- Y02A: TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE

## Abstract

Systems and methods for processing sensor analyte data, including initiating calibration, updating calibration, evaluating clinical acceptability of reference and sensor analyte data, and evaluating the quality of sensor calibration. During initial calibration, the analyte sensor data is evaluated over a period of time to determine stability of the sensor. The sensor may be calibrated using a calibration set of one or more matched sensor and reference analyte data pairs. The calibration may be updated after evaluating the calibration set for best calibration based on inclusion criteria with newly received reference analyte data. Fail-safe mechanisms are provided based on clinical acceptability of reference and analyte data and quality of sensor calibration. Algorithms provide for optimized prospective and retrospective analysis of estimated blood analyte data from an analyte sensor.

## Claims

### Claim 1

A method for evaluating a calibration of an analyte sensor, the method comprising:
receiving sensor data from an analyte sensor, during a time period of continuous analyte sensing of a host, including one or more sensor data points;
receiving reference data, during the time period of continuous analyte sensing of the host, including one or more reference data points;
providing one or more matched data pairs by matching a reference data point to a substantially time corresponding sensor data point;
forming a calibration set including the one or more matched data pairs;
evaluating, during the time period of continuous analyte sensing of the host, a clinical acceptability of the one or more matched data pairs, wherein the clinical acceptability is based at least in part on a clinical error grid analysis; and
processing the sensor data in response to the clinical acceptability of the one or more matched data pairs meeting a criterion.

### Claim 2 (depends on 1)

The method of claim 1, wherein receiving sensor data comprises receiving sensor data that has been smoothed.

### Claim 3 (depends on 1)

The method of claim 1, wherein receiving sensor data comprises smoothing the sensor data.

### Claim 4 (depends on 1)

The method of claim 1, wherein the sensor data is recursively filtered.

### Claim 5 (depends on 1)

The method of claim 1, wherein receiving sensor data comprises receiving the sensor data from a substantially continuous glucose sensor.

### Claim 6 (depends on 1)

The method of claim 1, wherein receiving reference data comprises receiving reference data from an in vitro blood glucose test.

### Claim 7 (depends on 1)

The method of claim 1, wherein receiving reference data comprises downloading reference data via a wireless connection.

### Claim 8 (depends on 1)

The method of claim 1, wherein receiving reference data comprises receiving within a receiver an internal communication from a reference analyte monitor integral with the receiver.

### Claim 9 (depends on 1)

The method of claim 1, wherein the calibration set comprises a single matched data pair.

### Claim 10 (depends on 1)

The method of claim 1, wherein the calibration set comprises a plurality of matched data pairs.

### Claim 11 (depends on 1)

The method of claim 1, wherein the clinical error grid analysis comprises a Clarke Error Grid or a Consensus Grid analysis.

### Claim 12 (depends on 1)

The method of claim 1, wherein processing the sensor data comprises calibrating the sensor data.

### Claim 13 (depends on 1)

The method of claim 1, wherein processing the sensor data comprises displaying the sensor data.

### Claim 14 (depends on 1)

The method of claim 1, further comprising requesting additional reference data in response to the clinical acceptability not meeting a criterion.

### Claim 15 (depends on 1)

The method of claim 1, further comprising modifying the calibration set based on the additional received reference data.

### Claim 16 (depends on 1)

The method of claim 1, further comprising removing a most discordant or oldest matched data pair in response to the clinical acceptability not meeting a criterion.

### Claim 17

A computer system for evaluating a calibration of an analyte sensor, the method comprising:
a sensor data receiving module configured to receive, during a time period of continuous analyte sensing of a host, a data stream comprising one or more sensor data points;
a reference data receiving module configured to receive, during the time period of continuous analyte sensing of the host, reference data, including one or more reference data points;
a data matching module configured to form one or more matched data pairs by matching one or more reference data points to one or more substantially time corresponding sensor data points;
a calibration set module configured to form a calibration set including the one or more matched data pairs;
an evaluation module configured to evaluate, during the time period of continuous analyte sensing of the host, a clinical acceptability of the one or more matched data pairs, wherein the clinical acceptability is based at least in part on a clinical error grid analysis; and
a processor module configured to process the sensor data in response to the clinical acceptability of the one or more matched data pairs meeting a criterion.

### Claim 18 (depends on 17)

The computer system of claim 17, wherein reference data receiving module is configured to receive sensor data that has been smoothed.

### Claim 19 (depends on 17)

The computer system of claim 17, wherein the reference data receiving module is configured to smooth the sensor data.

### Claim 20 (depends on 17)

The computer system of claim 17, wherein the sensor data is recursively filtered.

### Claim 21 (depends on 17)

The computer system of claim 17, wherein the reference data receiving module is configured to receive the sensor data from a substantially continuous glucose sensor.

### Claim 22 (depends on 17)

The computer system of claim 17, wherein reference data receiving module is configured to receive the reference data from an in vitro blood glucose test.

### Claim 23 (depends on 17)

The computer system of claim 17, wherein reference data receiving module is configured to download the reference data via a wireless connection.

### Claim 24 (depends on 17)

The computer system of claim 17, wherein reference data receiving module is configured to receive within a receiver an internal communication from a reference analyte monitor integral with the receiver.

### Claim 25 (depends on 17)

The computer system of claim 17, wherein the calibration set comprises a single matched data pair.

### Claim 26 (depends on 17)

The computer system of claim 17, wherein the calibration set comprises a plurality of matched data pairs.

### Claim 27 (depends on 17)

The computer system of claim 17, wherein the clinical error grid analysis comprises a Clarke Error Grid or a Consensus Grid analysis.

### Claim 28 (depends on 17)

The computer system of claim 17, wherein the processor module is configured to calibrate the sensor data in response to the clinical acceptability meeting a criterion.

### Claim 29 (depends on 17)

The computer system of claim 17, wherein the processor module is configured to display the sensor data in response to the clinical acceptability meeting a criterion.

### Claim 30 (depends on 17)

The computer system of claim 17, wherein the evaluation module is configured to request additional reference data in response to the clinical acceptability meeting a criterion.

### Claim 31 (depends on 17)

The computer system of claim 17, wherein the evaluation module or the calibration set module is configured to add a matched data pair to the calibration set based on the additional received reference data in response to the clinical acceptability meeting a criterion.

### Claim 32 (depends on 17)

The computer system of claim 17, wherein the evaluation module or the calibration set module is configured to remove a most discordant or oldest matched data pair in response to the clinical acceptability meeting a criterion.