Method and System for Providing Calibration of an Analyte Sensor in an Analyte Monitoring System

Abstract

Method and apparatus for providing calibration of analyte sensor including applying a control signal, detecting a measured response to the control signal, determining a variance in the detected measured response, and estimating a sensor sensitivity based on the variance in the detected measured response is provided

1 . (canceled) 
     
     
         2 . A method for calibrating an analyte sensor, the method comprising:
 applying a time-varying signal to the analyte sensor;   measuring a signal response to the applied signal;   determining, using sensor electronics, a sensitivity of the analyte sensor, the determining comprising correlating at least one property of the signal response to a predetermined sensor sensitivity profile; and   generating, using sensor electronics, estimated analyte concentration values using the determined sensitivity and sensor data generated by the analyte sensor.   
     
     
         3 . The method of  claim 2 , wherein the sensitivity profile comprises varying sensitivity values over time since implantation of the sensor. 
     
     
         4 . The method of  claim 2 , wherein the predetermined sensitivity profile comprises a plurality of sensitivity values. 
     
     
         5 . The method of  claim 2 , wherein the predetermined sensitivity profile is based on sensor sensitivity data generated from studying sensitivity changes of analyte sensors similar to the analyte sensor. 
     
     
         6 . The method of  claim 2 , further comprising applying a bias voltage to the sensor, wherein the time-varying signal comprises a step voltage above the bias voltage or a sine wave overlaying a voltage bias voltage. 
     
     
         7 . The method of  claim 2 , wherein the determining further comprises calculating an impedance value based on the measured signal response and correlating the impedance value to a sensitivity value of the predetermined sensitivity profile. 
     
     
         8 . The method of  claim 2 , further comprising applying a DC bias voltage to the sensor to generate sensor data, wherein the estimating analyte concentration values includes generating corrected sensor data using the determined sensitivity. 
     
     
         9 . The method of  claim 8 , further comprising applying a conversion function to the corrected sensor data to generate the estimated analyte concentration values. 
     
     
         10 . The method of  claim 8 , further comprising forming a conversion function based at least in part of the determined sensitivity, and wherein the conversion function is applied to the sensor data to generate the estimated analyte concentration values. 
     
     
         11 . The method of  claim 2 , wherein the property is a peak current value of the signal response. 
     
     
         12 . The method of  claim 2 , wherein the determining further comprises using at least one of performing a Fast Fourier Transform on the signal response data, integrating at least a portion of a curve of the signal response, and determining a peak current of the signal response. 
     
     
         13 . The method of  claim 12 , further comprising generating estimated analyte concentration values using the selected sensitivity profile. 
     
     
         14 . The method of  claim 2 , wherein the determining further comprises selecting the predetermined sensitivity profile based on the determined sensor property from a plurality of different predetermined sensitivity profiles. 
     
     
         15 . The method of  claim 14 , wherein the selecting includes performing a data association analysis to determine a correlation between the determined sensor property and each of the plurality of different predetermined sensitivity profiles and wherein the selected predetermined sensitivity profile has the highest correlation. 
     
     
         16 . The method of  claim 14 , further comprising generating estimated analyte concentration values using the selected sensitivity profile. 
     
     
         17 . The method of  claim 16 , further comprising determining a second sensitivity value using the selected sensitivity profile, wherein a first set of estimated analyte concentration values is generated using the determined sensitivity value and sensor data associated with a first time period, and wherein a second set of concentration values is generated using the second sensitivity value and sensor data associated with a second time period. 
     
     
         18 . A system for measuring an analyte, the system comprising sensor electronics configured to be operably connected to a continuous analyte sensor, the sensor electronics configured to:
 apply a time-varying signal to the analyte sensor;   measure a signal response to the applied signal;   determine a sensitivity of the analyte sensor, the determining comprising correlating at least one property of the signal response to a predetermined sensor sensitivity profile; and   generate estimated analyte concentration values using the determined sensitivity and sensor data generated by the analyte sensor.   
     
     
         19 . The system of  claim 18 , wherein the sensitivity profile comprises varying sensitivity values over time since implantation of the sensor. 
     
     
         20 . The system of  claim 18 , wherein the predetermined sensitivity profile comprises a plurality of sensitivity values. 
     
     
         21 . The system of  claim 18 , wherein the predetermined sensitivity profile is based on sensor sensitivity data generated from studying sensitivity changes of analyte sensors similar to the analyte sensor. 
     
     
         22 . The system of  claim 18 , wherein the sensor electronics are further configured to apply a bias voltage to the sensor, wherein the time-varying signal comprises a step voltage above the bias voltage or a sine wave overlaying a voltage bias voltage. 
     
     
         23 . The system of  claim 18 , wherein the determining further comprises calculating an impedance value based on the measured signal response and correlating the impedance value to a sensitivity value of the predetermined sensitivity profile. 
     
     
         24 . The system of  claim 18 , wherein the sensor electronics are further configured to apply a DC bias voltage to the sensor to generate sensor data, wherein the estimating analyte concentration values includes generating corrected sensor data using the determined sensitivity. 
     
     
         25 . The system of  claim 18 , wherein the sensor electronics are further configured to apply a conversion function to the corrected sensor data to generate the estimated analyte concentration values. 
     
     
         26 . The system of  claim 18 , wherein the sensor electronics are further configured to form a conversion function based at least in part of the determined sensitivity, and wherein the conversion function is applied to the sensor data to generate the estimated analyte concentration values. 
     
     
         27 . The system of  claim 18 , wherein the property is a peak current value of the signal response. 
     
     
         28 . The system of  claim 18 , wherein the determining further comprises using at least one of performing a Fast Fourier Transform on the signal response data, integrating at least a portion of a curve of the signal response, and determining a peak current of the signal response. 
     
     
         29 . The system of  claim 28 , wherein the sensor electronics are further configured to generate estimated analyte concentration values using the selected sensitivity profile. 
     
     
         30 . The system of  claim 18 , wherein the determining further comprises selecting the predetermined sensitivity profile based on the determined sensor property from a plurality of different predetermined sensitivity profiles. 
     
     
         31 . The system of  claim 30 , wherein the selecting includes performing a data association analysis to determine a correlation between the determined sensor property and each of the plurality of different predetermined sensitivity profiles and wherein the selected predetermined sensitivity profile has the highest correlation. 
     
     
         32 . The system of  claim 30 , wherein the system electronics are further configured to generate estimated analyte concentration values using the selected sensitivity profile. 
     
     
         33 . The system of  claim 32 , wherein the system electronics are further configured to determine a second sensitivity value using the selected sensitivity profile, wherein a first set of estimated analyte concentration values is generated using the determined sensitivity value and sensor data associated with a first time period, and wherein a second set of concentration values is generated using the second sensitivity value and sensor data associated with a second time period. 
     
     
         34 . The system of  claim 18 , wherein the sensor electronics comprise a processor module, the processor module comprising instructions stored in computer memory, wherein the instructions, when executed by the processor module, cause the sensor electronics to perform the applying, the measuring, the determining and the generating.