ANALYTE SENSOR

• US 20090242425A1
• Filed: 03/25/2008
• Published: 10/01/2009
• Est. Priority Date: 03/25/2008
• Status: Active Grant

• Current Assignee: DexCom Incorporated
• Original Assignee: DexCom Incorporated
• Inventors: Kamath, Apurv Ullas, Brister, Mark, Simpson, Peter C.
• Granted Patent: US 8,396,528 B2
• Time in Patent Office: Days
• US Class Current: 205/777.500
• CPC Class Codes: A61B 2560/0223 of calibration, e.g. protocols for calibrating sensors
• CPC Class Codes: A61B 5/14532 for measuring glucose, e.g. by tissue impedance measurement
• 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 5/1455 using optical sensors, e.g. spectral photometrical oximeters
• CPC Class Codes: A61B 5/14551 for measuring blood gases
• CPC Class Codes: A61B 5/1459 invasive, e.g. introduced into the body by a catheter A61B5/1464 takes precedence
• 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 5/4094 Diagnosing or monitoring seizure diseases, e.g. epilepsy
• CPC Class Codes: A61B 5/6852 Catheters
• CPC Class Codes: A61B 5/7203 for noise prevention, reduction or removal

Abstract

Systems and methods of use for continuous analyte measurement of a host'"'"'s vascular system are provided. In some embodiments, a continuous glucose measurement system includes a vascular access device, a sensor and sensor electronics, the system being configured for insertion into communication with a host'"'"'s circulatory system.

Claims

1. A continuous analyte detection system, comprising:

a continuous analyte sensor configured for contact with a sample from a circulatory system of a host and configured to generate a first signal and a second signal, wherein the first signal is associated with a test analyte and the second signal is associated with a reference analyte;

a reference sensor configured to generate a reference signal associated with the reference analyte; and

a processor module configured to process the second signal and the reference signal to calibrate the first signal.

2. The system of claim 1, wherein the continuous analyte sensor comprises a first working electrode and a second working electrode, wherein the first working electrode is disposed beneath an active enzymatic portion of a sensor membrane and is configured to generate a signal associated with analyte and non-analyte related electroactive compounds, wherein the non-analyte related electroactive compounds have an oxidation potential that substantially overlaps with an oxidation potential of the analyte;

wherein the second working electrode is disposed beneath an inactive-enzymatic or a non-enzymatic portion of the sensor membrane and is configured to generate a signal associated with the non-analyte-related electroactive species, and wherein the processor module is configured to process signals from the first working electrode and second working electrode whereby a first signal substantially without a non-analyte-related signal component is generated.

3. The system of claim 2, wherein the first working electrode is further configured to generate the second signal.

4. The system of claim 2, wherein the second working electrode is further configured to generate the second signal.

5. The system of claim 2, wherein the continuous analyte sensor further comprises a third working electrode disposed beneath the sensor membrane and configured to generate the second signal.

6. The system of claim 1, wherein the reference sensor comprises an optical sensing apparatus.

7. The system of claim 1, wherein the reference sensor is disposed in a same local environment as the continuous analyte sensor.

8. The system of claim 1, wherein the continuous analyte sensor comprises a working electrode configured to generate both the first signal and the second signal.

9. The system of claim 1, further comprising a flow control device configured to meter a flow of a fluid.

10. A method for measuring an analyte in a host, comprising:

exposing a continuous analyte detection system to a sample, wherein the continuous analyte detection system comprises a continuous analyte sensor configured for contact with a sample from a circulatory system of a host in vivo and configured to generate a first signal associated with a test analyte and a second signal associated with a reference analyte, and a reference sensor configured to generate a reference signal associated with the reference analyte;

receiving the first signal, the second signal, and the reference signal;

calculating a calibration factor associated with a sensitivity of the continuous analyte sensor; and

calibrating the first signal, wherein calibrating comprises using the calibration factor.

11. The method of claim 10, wherein the exposing step further comprises simultaneously exposing the continuous analyte sensor and the reference sensor to the sample.

12. The method of claim 10, wherein the receiving step further comprises receiving the first signal from a first working electrode disposed under an enzymatic portion of a membrane system.

13. The method of claim 12, wherein the receiving step further comprises receiving the second signal from the first working electrode.

14. The method of claim 12, wherein the receiving step further comprises receiving the second signal from a second working electrode disposed under the membrane system.

15. The method of claim 14, wherein the receiving step further comprises receiving a non-analyte-related signal from the second working electrode, wherein the second working electrode is disposed under a non-enzymatic portion of the membrane system.

16. The method of claim 14, wherein the receiving step further comprises receiving a non-analyte-related signal from a third working electrode disposed under a non-enzymatic portion of the membrane system.

17. The method of claim 10, wherein the receiving step further comprises optically detecting the reference analyte.

18. The method of claim 10, wherein the receiving step further comprises receiving a first signal associated with a glucose concentration of the sample.

19. The method of claim 10, wherein the receiving step further comprises receiving a second signal associated with an oxygen concentration of the sample, and a reference signal associated with the oxygen concentration of the sample.

20. The method of claim 10, wherein the exposing step comprises exposing the continuous analyte detection system to a bodily fluid and the calculating step further comprises comparing steady-state information of the first signal and steady-state information of the second signal.

21. The method of claim 10, the exposing step comprises exposing the continuous analyte detection system to a substantially stagnant non-bodily fluid during a time period and the calculating step further comprises comparing a signal increase on each of the first and second working electrodes during the time period.

22. A continuous analyte detection system, comprising:

an analyte sensor comprising a membrane system, wherein the analyte sensor is configured to generate a measurement signal associated with a measurement analyte concentration in vivo and wherein the analyte sensor is further configured to generate a reference signal associated with a reference analyte concentration in vivo;

a reference sensor located proximal to the analyte sensor and configured to generate a reference value associated with the reference analyte, wherein the reference sensor is located proximal to the analyte sensor; and

a processor module configured to process the reference signal and the reference value to calibrate the measurement signal.

23. The system of claim 22, wherein the processor module is configured to calibrate the measurement signal without an external reference value.

24. The system of claim 22, wherein the system is configured for automatic calibration of the measurement signal.

25. The system of claim 22, wherein the system is configured such that the analyte sensor and the reference sensor are located within the same local environment such that the reference concentration measured by the analyte sensor and the reference concentration measured by the reference sensor are substantially equal.

26. The system of claim 22, wherein the analyte sensor is an electrochemical sensor and the reference sensor is an optical sensor.