Advanced analyte sensor calibration and error detection

• US 10,722,162 B2
• Filed: 09/27/2019
• Issued: 07/28/2020
• 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:
  US16/586,407
• Publication Number:
  US 20200037934A1
• Time in Patent Office: 305 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. An analyte sensor system comprising:

a transcutaneous electrochemical analyte sensor comprising;

a first portion configured to remain ex vivo during a sensor session; and

a second portion configured to be disposed in vivo during the sensor session, wherein the second portion comprises an electrode configured to generate a signal associated with an analyte concentration; and

a membrane disposed over at least a portion of the electrode; and

sensor electronics operably connectable to the transcutaneous electrochemical analyte sensor, wherein the sensor electronics comprise a memory storing information associated with sensor sensitivity, wherein the information associated with sensor sensitivity is based at least in part on information based on a measurement of at least one sensor characteristic of the transcutaneous electrochemical analyte sensor during or after manufacturing of the transcutaneous electrochemical analyte sensor but prior to a sensor session;

wherein the measured at least one sensor characteristic is associated with a thickness of the membrane.

2. The analyte sensor system of claim 1, wherein the sensor electronics are configured to process sensor data measured by the transcutaneous electrochemical analyte sensor to generate displayable sensor information.

3. The analyte sensor system of claim 1, further comprising a display device.

4. The analyte sensor system of claim 1, wherein the transcutaneous electrochemical analyte sensor is comprises a wire.

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

6. The analyte sensor system of claim 1, further comprising a temperature sensor configured to measure an ex vivo temperature, wherein the analyte sensor system, during processing of the signal, is configured to perform temperature compensation by accounting for the measured ex vivo temperature.

7. The analyte sensor system of claim 1, wherein the sensor electronics are configured to process the signal.

8. The analyte sensor system of claim 7, wherein the sensor electronics are configured to process the signal based at least in part on the information associated with sensor sensitivity.

9. The analyte sensor system of claim 7, further comprising a receiver, wherein the receiver is configured to further process the processed signal based at least in part on the information associated with sensor sensitivity.

10. The analyte sensor system of claim 7, wherein the sensor electronics are configured to transmit the processed signal and the information associated with sensor sensitivity to a receiver for further processing to determine an estimated analyte value.

11. The analyte sensor system of claim 10, wherein the receiver is a handheld device, and wherein the handheld device is a smart phone.

12. The analyte sensor system of claim 1, wherein the membrane further comprises a polymer having a mediator.

13. The analyte sensor system of claim 1, wherein the analyte sensor system is configured to calibrate the transcutaneous electrochemical analyte sensor without reference to any blood glucose data obtained during the sensor session.

14. The analyte sensor system of claim 1, wherein the membrane is a membrane system comprising a plurality of different membrane layers.

15. The analyte sensor system of claim 1, wherein the membrane is a membrane layer.

16. A non-transient computer readable memory incorporated into an analyte sensor system, the non-transient computer readable memory having instructions stored therein that cause the analyte sensor system to perform the method of:

storing information associated with sensor sensitivity, wherein the information associated with sensor sensitivity is configured to be used to convert sensor data into estimated analyte values;

wherein the information associated with sensitivity is based at least in part on pre-implant information;

receiving sensor data generated by a transcutaneous electrochemical analyte sensor, wherein the transcutaneous electrochemical analyte sensor comprises a first portion configured to remain ex vivo during a sensor session and second portion configured to be disposed in vivo in a host during the sensor session, wherein the second portion comprises an electrode, wherein the electrode is covered at least in part by a membrane;

processing the sensor data generated by the transcutaneous electrochemical analyte sensor to generate displayable sensor information; and

wherein the pre-implant information is based at least in part on information from a measurement of at least one sensor characteristic associated with fabrication of the transcutaneous electrochemical analyte sensor, wherein the measured at least one sensor characteristic is associated with a thickness of at least a portion of the membrane.

17. The non-transient computer readable memory of claim 16, wherein the method further comprises outputting the estimated analyte values on a display.

18. The non-transient computer readable memory of claim 16, wherein the analyte is glucose.

19. The non-transient computer readable memory of claim 16, wherein the displayable sensor information comprises substantially raw sensor data or transformed sensor data.

20. The non-transient computer readable memory of claim 16, wherein the displayable sensor information comprises estimated analyte values.

21. An analyte sensor system comprising:

a transcutaneous electrochemical analyte sensor comprising;

a first portion configured to remain ex vivo during a sensor session;

a second portion configured to be disposed in vivo in a host during the sensor session, wherein the second portion comprises an electrode configured to generate at least one data point indicative of analyte concentration;

a membrane disposed on at least a portion of the electrode; and

a control system configured to;

use a calibration code associated with the transcutaneous electrochemical analyte sensor, wherein the calibration code is based at least in part on information from a measurement of at least one sensor characteristic of the transcutaneous electrochemical analyte sensor during or after manufacturing of the transcutaneous electrochemical analyte sensor but before a sensor session, wherein the measured at least one sensor characteristic is associated with a thickness of the membrane;

receive the at least one sensor data point from the transcutaneous electrochemical analyte sensor; and

convert, in real-time, the at least one sensor data point to an estimated analyte value.

22. The analyte sensor system of claim 21, wherein the control system is further configured to display the estimated analyte value.

23. The analyte sensor system of claim 21, wherein the analyte is glucose.

24. The analyte sensor system of claim 21, further comprising a temperature sensor configured to measure an ex vivo temperature, wherein the control system is configured to convert, in real-time, the at least one sensor data point to an estimated analyte value, based at least in part on the measured ex vivo temperature.

25. The analyte sensor system of claim 21, wherein the membrane is a membrane system comprising a plurality of different membrane layers.

26. The analyte sensor system of claim 21, wherein the membrane is a membrane layer.

27. The analyte sensor system of claim 21, further comprising sensor electronics configured to operably connect with the sensor.

28. The analyte sensor system of claim 27, wherein the control system is a component of the sensor electronics.

29. The analyte sensor system of claim 27, wherein the sensor electronics is configured to operably connect with a receiver, wherein the control system is a component of the receiver.

30. The analyte sensor system of claim 29, wherein the control system is a software on the receiver.