Advanced analyte sensor calibration and error detection

• US 10,835,162 B2
• Filed: 09/27/2019
• Issued: 11/17/2020
• Est. Priority Date: 04/15/2011
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Bohm, Sebastian, Rong, Daiting, Simpson, Peter C.
• Primary Examiner(s): Previl, Daniel
• Application Number:
  US16/586,610
• Publication Number:
  US 20200037936A1
• Time in Patent Office: 417 Days
• Field of Search: 340604, 340612, 34063611, 34063612-63615, 3406916
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 2560/0276 Determining malfunction
• CPC Class Codes: A61B 2560/04 Constructional details of apparatus
• CPC Class Codes: A61B 2562/085 combined with means for recording calibration data
• 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 5/14517 for sweat
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• CPC Class Codes: A61B 5/14535 for measuring haematocrit
• CPC Class Codes: A61B 5/14539 for measuring pH
• CPC Class Codes: A61B 5/14542 for measuring blood gases A61B5/14551 takes precedence
• CPC Class Codes: A61B 5/14546 for measuring analytes not otherwise provided for, e.g. ions, cytochromes
• 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: A61B 5/15003 for venous or arterial blood
• CPC Class Codes: A61B 5/150992 Blood sampling from a fluid line external to a patient, such as a catheter line, combined with an infusion line; blood sampling from indwelling needle sets, e.g. sealable ports, luer couplings, valves tubing connectors and couplings A61M39/00
• CPC Class Codes: A61B 5/155 : Devices specially adapted for continuous or multiple sampling, e.g. at predetermined intervals devices loaded with multiple lancets simultaneously A61B5/15146
• CPC Class Codes: A61B 5/157 : Devices characterised by integrated means for measuring characteristics of blood
• CPC Class Codes: A61B 5/412 : Detecting or monitoring sepsis
• CPC Class Codes: A61B 5/4839 : combined with drug delivery
• CPC Class Codes: A61B 5/6848 : Needles
• CPC Class Codes: A61B 5/6849 : in combination with a needle set
• CPC Class Codes: A61B 5/6866 : Extracorporeal blood circuits, e.g. dialysis circuits
• CPC Class Codes: A61B 5/7257 : using Fourier transforms
• CPC Class Codes: A61B 5/7267 : involving training the classification device
• CPC Class Codes: A61B 5/7275 : Determining trends in physiological measurement data; Predicting development of a medical condition based on physiological measurements, e.g. determining a risk factor
• CPC Class Codes: A61B 5/743 : Displaying an image simultaneously with additional graphical information, e.g. symbols, charts, function plots
• CPC Class Codes: A61M 2005/14296 : Pharmacokinetic models
• CPC Class Codes: A61M 2230/201 : Glucose concentration
• CPC Class Codes: A61M 5/14 : Infusion devices, e.g. infusing by gravity; Blood infusion; Accessories therefor
• CPC Class Codes: A61M 5/16804 : Flow controllers
• CPC Class Codes: A61M 5/1723 : using feedback of body parameters, e.g. blood-sugar, pressure measurement of body parameters A61B5/00
• CPC Class Codes: C12Q 1/001 : Enzyme electrodes
• CPC Class Codes: C12Q 1/006 : for glucose
• CPC Class Codes: G01D 18/00 : Testing or calibrating apparatus or arrangements provided for in groups G01D1/00 - G01D15/00
• CPC Class Codes: G01N 27/026 : Dielectric impedance spectroscopy electrochemical impedance spectroscopy for measuring corrosion G01N17/02
• CPC Class Codes: G01N 27/3274 : Corrective measures, e.g. error detection, compensation for temperature or hematocrit, calibration coding of calibration information G01N33/48771
• CPC Class Codes: G01N 33/49 : Blood chemical methods for determining blood cell populations G01N33/5094; chemical analysis of blood groups or blood types G01N33/80
• CPC Class Codes: G16H 10/40 : for data related to laboratory analysis, e.g. patient specimen analysis
• CPC Class Codes: G16H 20/17 : delivered via infusion or injection
• CPC Class Codes: G16H 40/40 : for the management of medical equipment or devices, e.g. scheduling maintenance or upgrades
• CPC Class Codes: G16H 40/63 : for local operation
• CPC Class Codes: H05K 999/00 : dummy group
• CPC Class Codes: H05K 999/99 : dummy group
• 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 data and self-calibration are provided. In some embodiments, systems and methods are provided which are capable of calibrating a continuous analyte sensor based on an initial sensitivity, and then continuously performing self-calibration without using, or with reduced use of, reference measurements. In certain embodiments, a sensitivity of the analyte sensor is determined by applying an estimative algorithm that is a function of certain parameters. Also described herein are systems and methods for determining a property of an analyte sensor using a stimulus signal. The sensor property can be used to compensate sensor data for sensitivity drift, or determine another property associated with the sensor, such as temperature, sensor membrane damage, moisture ingress in sensor electronics, and scaling factors.

Claims

1. A method comprising:

manufacturing a plurality of transcutaneous electrochemical glucose sensors, wherein the plurality of transcutaneous electrochemical glucose sensors comprise a first transcutaneous electrochemical glucose sensor, wherein the first transcutaneous electrochemical glucose sensor is configured to measure glucose in an interstitial fluid of the host, wherein the first transcutaneous electrochemical glucose sensor comprises an ex vivo portion and an in vivo portion, wherein the first transcutaneous electrochemical glucose sensor is configured to operably connect to sensor electronics during a sensor session;

obtaining data associated with a first characteristic of the first transcutaneous electrochemical glucose sensor prior to the sensor session;

determining, based at least in part on the data associated with the first characteristic, a first sensitivity associated with the first transcutaneous electrochemical glucose sensor;

assigning a calibration code to the first transcutaneous electrochemical glucose sensor, wherein the calibration code is based at least in part on the first sensitivity;

storing information associated with the calibration code on the sensor electronics;

obtaining data associated with a second characteristic of the first transcutaneous electrochemical glucose sensor during the sensor session;

determining, based at least in part on the data associated with the second characteristic, a second sensitivity associated with the first transcutaneous electrochemical glucose sensor;

generating, based at least in part on the second sensitivity, a glucose value associated with an estimated glucose concentration; and

displaying the glucose value on a user interface.

2. The method of claim 1, wherein the calibration code is part of a calibration encoded label.

3. The method of claim 1, wherein the first transcutaneous electrochemical glucose sensor is formed as a wire.

4. The method of claim 1, further comprising measuring a length of time the first transcutaneous electrochemical glucose sensor was dipped in a particular coating solution, and wherein the calibration code is further based at least in part on the measured dipping length of time.

5. The method of claim 1, wherein the first transcutaneous electrochemical glucose sensor comprises a membrane, wherein the first characteristic of the first transcutaneous electrochemical glucose sensor is associated with a thickness of the membrane of the first transcutaneous electrochemical glucose sensor.

6. The method of claim 5, wherein the membrane is a membrane system.

7. The method of claim 5, wherein the membrane is a membrane layer.

8. The method of claim 1, wherein the first transcutaneous electrochemical glucose sensor comprises a membrane, wherein the first characteristic of the first transcutaneous electrochemical glucose sensor is associated with a permeability of the membrane to glucose.

9. The method of claim 1, wherein the first transcutaneous electrochemical glucose sensor comprises a membrane, wherein the first characteristic of the first transcutaneous electrochemical glucose sensor is associated with a property of the membrane.

10. The method of claim 1, wherein the second characteristic of the first transcutaneous electrochemical glucose sensor is associated with a measured temperature.

11. The method of claim 1, wherein the first sensitivity is a sensitivity value.

12. The method of claim 1, wherein the first sensitivity is a sensitivity distribution.

13. The method of claim 1, wherein the second sensitivity is a sensitivity value.

14. The method of claim 1, wherein the second sensitivity is a sensitivity distribution.

15. A method comprising:

manufacturing a plurality of transcutaneous electrochemical glucose sensors, wherein the plurality of transcutaneous electrochemical glucose sensors comprise a first transcutaneous electrochemical glucose sensor, wherein the first transcutaneous electrochemical glucose sensor is configured to measure glucose in an interstitial fluid of the host, wherein the first transcutaneous electrochemical glucose sensor comprises an ex vivo portion and an in vivo portion, wherein the first transcutaneous electrochemical glucose sensor is configured to operably connect to sensor electronics during a sensor session;

determining a first distribution associated with a sensitivity of the first transcutaneous electrochemical glucose sensor;

obtaining data associated with a characteristic of the first transcutaneous electrochemical glucose sensor prior to the sensor session; and

determining, based at least in part on the first distribution and based at least in part on the data associated with the characteristic of the first transcutaneous electrochemical glucose sensor, a second distribution associated with sensor sensitivity of the first transcutaneous electrochemical glucose sensor.

16. The method of claim 15, wherein the first transcutaneous electrochemical glucose sensor comprises a membrane, wherein the characteristic of the first transcutaneous electrochemical glucose sensor is associated with a thickness of the membrane of the first transcutaneous electrochemical glucose sensor.

17. The method of claim 15, wherein the first transcutaneous electrochemical glucose sensor comprises a membrane, wherein the characteristic of the first transcutaneous electrochemical glucose sensor is associated with a permeability of the membrane to glucose.

18. The method of claim 15, wherein the first transcutaneous electrochemical glucose sensor comprises a membrane, wherein the characteristic of the first transcutaneous electrochemical glucose sensor is associated with a property of the membrane.

19. A method comprising:

manufacturing a plurality of transcutaneous electrochemical glucose sensors, wherein the plurality of transcutaneous electrochemical glucose sensors comprise a first transcutaneous electrochemical glucose sensor, wherein the first transcutaneous electrochemical glucose sensor is configured to measure glucose in an interstitial fluid of the host, wherein the first transcutaneous electrochemical glucose sensor comprises an ex vivo portion and an in vivo portion, wherein the first transcutaneous electrochemical glucose sensor is configured to operably connect to sensor electronics during a sensor session;

determining a distribution associated with a sensitivity of the first transcutaneous electrochemical glucose sensor;

obtaining data associated with a characteristic of the first transcutaneous electrochemical glucose sensor prior to the sensor session; and

determining, based at least in part on the first distribution and based at least in part on the data associated with the characteristic of the first transcutaneous electrochemical glucose sensor, a value associated with a sensitivity of the first transcutaneous electrochemical glucose sensor.

20. The method of claim 19, wherein the first transcutaneous electrochemical glucose sensor comprises a membrane, wherein the characteristic of the first transcutaneous electrochemical glucose sensor is associated with a thickness of the membrane of the first transcutaneous electrochemical glucose sensor.

21. The method of claim 19, wherein the first transcutaneous electrochemical glucose sensor comprises a membrane, wherein the characteristic of the first transcutaneous electrochemical glucose sensor is associated with a permeability of the membrane to glucose.

22. The method of claim 19, wherein the first transcutaneous electrochemical glucose sensor comprises a membrane, wherein the characteristic of the first transcutaneous electrochemical glucose sensor is associated with a property of the membrane.

23. A method comprising:

manufacturing a plurality of transcutaneous electrochemical glucose sensors, wherein the plurality of transcutaneous electrochemical glucose sensors comprise a first transcutaneous electrochemical glucose sensor and a second transcutaneous electrochemical glucose sensor, wherein the first transcutaneous electrochemical glucose sensor and the second transcutaneous electrochemical analyte sensor are each configured to measure glucose in an interstitial fluid of a host, wherein the first transcutaneous electrochemical glucose sensor and the second transcutaneous electrochemical glucose sensor each comprises an ex vivo portion and an in vivo portion, wherein the first transcutaneous electrochemical glucose sensor and the second transcutaneous electrochemical glucose sensor are each configured to operably connect to sensor electronics during a sensor session;

obtaining data associated with a characteristic of the first transcutaneous electrochemical glucose sensor prior to the sensor session;

determining, based at least in part on the data associated with the first transcutaneous electrochemical glucose sensor, a first sensitivity, wherein the first sensitivity is associated with a sensitivity of the first transcutaneous electrochemical glucose sensor;

assigning, to the first transcutaneous electrochemical glucose sensor, a first code associated with calibration, wherein the first code is associated with the first sensitivity;

obtaining data associated with a characteristic of the second transcutaneous electrochemical glucose sensor prior to the sensor session;

determining, based at least in part on the data associated with the second transcutaneous electrochemical glucose sensor, a second sensitivity, wherein the second sensitivity is associated with a sensitivity of the second transcutaneous electrochemical glucose sensor; and

assigning, to the second transcutaneous electrochemical glucose sensor, a second code associated with calibration, wherein the second code is associated with the second sensitivity;

wherein the first code and the second code are different.

24. The method of claim 23, wherein the characteristic of the first transcutaneous electrochemical glucose sensor and the characteristic of the second transcutaneous electrochemical glucose sensor are the same.

25. The method of claim 23, wherein the first transcutaneous electrochemical glucose sensor comprises a first membrane, wherein the second transcutaneous electrochemical glucose sensor comprises a second membrane, wherein the characteristic of the first transcutaneous electrochemical glucose sensor is associated with a thickness of the first membrane of the first transcutaneous electrochemical glucose sensor, wherein the characteristic of the second transcutaneous electrochemical glucose sensor is associated with a thickness of the second membrane of the second transcutaneous electrochemical glucose sensor.

26. The method of claim 23, wherein the first transcutaneous electrochemical glucose sensor comprises a first membrane, wherein the second transcutaneous electrochemical glucose sensor comprises a second membrane, wherein the characteristic of the first transcutaneous electrochemical glucose sensor is associated with a permeability of the first membrane to glucose, wherein the characteristic of the second transcutaneous electrochemical glucose sensor is associated with a permeability of the second membrane to glucose.

27. The method of claim 23, wherein the first transcutaneous electrochemical glucose sensor and the second transcutaneous each comprises a membrane, wherein the first characteristic of the first transcutaneous electrochemical glucose sensor and the second characteristic of the second transcutaneous electrochemical sensor are each associated with a property of the membrane.

28. The method of claim 23, wherein the first sensitivity and the second sensitivity are sensitivity values.

29. The method of claim 23, wherein the first sensitivity and the second sensitivity are sensitivity distributions.