System and methods for processing analyte sensor data for sensor calibration
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.
1. A method for calibrating data from a glucose sensor, wherein the glucose sensor is configured for transcutaneous implantation in a host while operably connected to sensor electronics, and wherein the glucose sensor comprises a membrane system, the method comprising:
receiving information associated with a priori sensitivity for the glucose sensor prior to implantation of the glucose sensor in the host, wherein the information associated with the a priori sensitivity is derived at least in part from an analysis of glucose sensor sensitivities collected from a set of glucose sensors that are representative of the glucose sensor with respect to a predictive relationship between in vivo and in vitro sensitivities;
receiving sensor data from the glucose sensor by the sensor electronics after the glucose sensor is implanted in the host, wherein the sensor data is representative of a glucose concentration in the host; and
calibrating, using a processor operably connected to the sensor electronics, the sensor data received from the glucose sensor, wherein the calibrating is performed based at least in part on the received information associated with the a priori sensitivity without reliance on reference glucose values obtained from a self-monitoring blood glucose test after implantation of the glucose sensor in the host.
2. The method of claim 1 , wherein the information associated with the a priori sensitivity is derived at least in part on an in vivo versus in vitro sensing relationship derived from clinical data obtained in at least one prior experiment using the representative set of glucose sensors.
3. The method of claim 1 , wherein the predictive relationship is represented by a function relating in vivo versus in vitro sensitivity.
4. The method of claim 3 , wherein the function is derived at least in part on an in vivo versus in vitro sensing relationship derived from clinical data obtained in at least one prior experiment using the representative set of glucose sensors.
5. The method of claim 4 , wherein the function is substantially linear.
6. The method of claim 5 , wherein the in vivo versus in vitro sensing relationship is associated with in vitro sensitivities being greater than corresponding in vivo sensitivities.
7. The method of claim 1 , comprising measuring a change in sensitivity and/or baseline based at least in part on one or more signals obtained from electrodes of the glucose sensor.
8. The method of claim 7 , further comprising calibrating the glucose sensor based at least in part on the measured change in sensitivity and/or baseline.
9. The method of claim 1 , comprising storing a sensor identifier in the memory.
10. The method of claim 1 , wherein the information associated with the a priori sensitivity comprises a slope and a baseline.
11. The method of claim 2 , wherein the information associated with the a priori sensitivity comprises a slope and a baseline.
12. The method of claim 1 , wherein the information associated with the a priori sensitivity comprises a calibration code.
13. The method of claim 2 , wherein the information associated with the a priori sensitivity comprises a calibration code.
14. The method of claim 1 , wherein the processor is part of the sensor electronics.
15. The method of claim 1 , comprising transmitting the sensor data to a receiver containing the processor.
16. The method of claim 1 , wherein the received information is a priori sensitivity data for the glucose sensor.
17. A system for calibrating signals received from an implanted glucose sensor, the system comprising:
a glucose sensor configured for transcutaneous implantation in a host, the glucose sensor comprising a membrane system and configured to generate sensor data representative of a glucose concentration in the host after implantation;
sensor electronics configured for attachment to the host and configured to be operably connected to the glucose sensor;
a processor configured to be operably connected to the sensor electronics;
memory configured to be operably connected to the processor, wherein the memory has stored therein information associated with a priori sensitivity, wherein the information associated with the a priori sensitivity is derived at least in part from an analysis of glucose sensor sensitivities collected from a set of glucose sensors that are representative of the glucose sensor with respect to a predictive relationship between in vivo and in vitro sensitivities; and
wherein the processor is configured to calibrate the glucose sensor based at least in part on the stored information associated with the a priori sensitivity without reliance on reference glucose values obtained from a self-monitoring blood glucose test after implantation of the glucose sensor in the host.
18. The system of claim 17 , wherein the predictive relationship is represented by a function relating in vivo versus in vitro sensitivity.
19. The system of claim 18 , wherein the function is derived at least in part on an in vivo versus in vitro sensing relationship derived from clinical data obtained in at least one prior experiment using the representative set of glucose sensors.
20. The system of claim 19 , wherein the function is substantially linear.
21. The system of claim 20 , wherein the in vivo versus in vitro sensing relationship is associated with in vitro sensitivities being greater than corresponding in vivo sensitivities.
22. The system of claim 17 , wherein the information associated with the a priori sensitivity is derived at least in part on an in vivo versus in vitro sensing relationship derived from clinical data obtained in at least one prior experiment using the representative set of glucose sensors.
23. The system of claim 17 , wherein the sensitivity information comprises a slope and a baseline.
24. The system of claim 17 , wherein the sensitivity information comprises a slope and a baseline.
25. The system of claim 17 , wherein the processor is incorporated into the sensor electronics.
26. The system of claim 17 , comprising a receiver configured to wirelessly receive the sensor data from the sensor electronics.
27. The system of claim 17 , wherein the processor is incorporated into the receiver.
28. The system of claim 17 , wherein the memory is incorporated into the sensor electronics.
29. The system of claim 17 , wherein the memory is incorporated into the receiver.