System and methods for processing analyte sensor data for sensor calibration

• US 9,220,449 B2
• Filed: 07/09/2013
• Issued: 12/29/2015
• Est. Priority Date: 03/10/2005
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Pryor, Jack, Kamath, Apurv Ullas, Goode, Paul V. Jr., Brauker, James H.
• Primary Examiner(s): Natnithithadha, Navin
• Application Number:
  US13/938,103
• Publication Number:
  US 20130296677A1
• Time in Patent Office: 903 Days
• US Class Current: 1/1
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/0031 Implanted circuitry
• CPC Class Codes: A61B 5/14503 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors A61B5/1459, A61B5/1464, A61B5/1473, A61B5/1482, A61B5/14865 take precedence
• CPC Class Codes: A61B 5/1451 for interstitial fluid
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• CPC Class Codes: A61B 5/1468 using chemical or electrochemical methods, e.g. by polarographic means A61B5/1486 takes precedence
• CPC Class Codes: A61B 5/1473 invasive, e.g. introduced into the body by a catheter A61B5/1482 takes precedence
• CPC Class Codes: A61B 5/14735 comprising an immobilised reagent
• CPC Class Codes: A61B 5/1486 using enzyme electrodes, e.g. with immobilised oxidase
• CPC Class Codes: A61B 5/14865 invasive, e.g. introduced into the body by a catheter or needle or using implanted sensors
• CPC Class Codes: A61B 5/1495 Calibrating or testing of in-vivo probes
• CPC Class Codes: Y02A 90/10 Information and communication technologies [ICT] supporting adaptation to climate change, e.g. for weather forecasting or climate simulation

Abstract

Systems and methods for processing sensor analyte data are disclosed, including initiating calibration, updating calibration, evaluating clinical acceptability of reference and sensor analyte data, and evaluating the quality of sensor calibration. The sensor can be calibrated using a calibration set of one or more matched sensor and reference analyte data pairs. Reference data resulting from benchtop testing an analyte sensor prior to its insertion can be used to provide initial calibration of the sensor data. Reference data from a short term continuous analyte sensor implanted in a user can be used to initially calibrate or update sensor data from a long term continuous analyte sensor.

Claims

1. A system for calibrating a continuous analyte sensor, comprising:

a continuous analyte sensor configured to provide sensor data indicative of an analyte concentration in a host; and

electronic circuitry configured to receive sensor data from a continuous analyte sensor comprising at least one sensor data point indicative of a glucose concentration in a host'"'"'s interstitial fluid, to receive reference data from a reference analyte monitor comprising at least one reference data point indicative of a glucose concentration in the host'"'"'s blood, and to determine a conversion function for converting the sensor data into estimated blood glucose values based on a most probable set of parameters based on one or more probability distributions.

2. The system of claim 1, wherein one or more matched data pairs are inputs into the determination of the conversion function, wherein the matched data pairs comprise at least one sensor data point matched with at least one reference data point.

3. The system of claim 1, wherein the most probable set of parameters is determined based on a probability analysis based on the one or more probability distributions.

4. The system of claim 3, wherein the probability analysis comprises determining a maximum joint probability based on the one or more probability distributions.

5. The system of claim 1, wherein the conversion function comprises a slope and a baseline.

6. The system of claim 1, wherein the electronic circuitry is configured to iteratively determine the conversion function responsive to receipt of new reference data.

7. The system of claim 1, wherein the conversion function comprises a linear function.

8. The system of claim 1, wherein the conversion function comprises a non-linear function.

9. The system of claim 1, comprising a quality measure associated with the calibration.

10. The system of claim 9, wherein the quality measure is based on a statistical data association.

11. The system of claim 9, wherein the quality measure is based on a clinical acceptability.

12. The system of claim 1, wherein the electronic circuitry is further configured to display the converted sensor data in substantially real time.

13. The system of claim 1, wherein the analyte is glucose.