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 a transcutaneous analyte sensor, comprising:
receiving sensor data from a transcutaneous analyte sensor, wherein the sensor data is indicative of an analyte concentration in a host;
determining a conversion function, using a processor module, wherein the conversion function comprises at least one of a slope or a baseline, wherein the slope is representative of a sensor sensitivity, and wherein the at least one of the slope or the baseline is determined by selecting a most probable slope and/or baseline based at least in part on prior distribution information of slopes or baselines, wherein the prior distribution information is generated before insertion of the transcutaneous analyte sensor in the host;
converting the sensor data using the conversion function;
generating an estimated analyte value based at least in part on the converted sensor data; and
displaying, on a display, the generated estimated analyte value.
2. The method of claim 1 , wherein determining the conversion function comprises determining the slope based at least in part on prior slope distribution information.
3. The method of claim 2 , wherein determining the slope comprises selecting a most probable slope from a distribution of slopes based at least in part on the prior slope distribution information.
4. The method of claim 1 , wherein determining the conversion function comprises determining the baseline based at least in part on prior baseline distribution information.
5. The method of claim 4 , wherein determining the baseline comprises selecting a most probable baseline from a distribution of baselines based at least in part on the prior baseline distribution information.
6. The method of claim 1 , wherein determining the conversion function comprises determining the slope and the baseline based at least in part on prior slope and baseline distribution information.
7. The method of claim 6 , wherein determining the slope and the baseline comprises selecting a most probable slope and baseline from a distribution of slopes and baselines based at least in part on the prior slope and baseline distribution information.
8. The method of claim 7 , wherein selecting the most probable slope and baseline comprises selecting a slope and baseline closest to the maximum joint probability of both the slope and baseline distributions.
9. The method of claim 1 , where determining the conversion function comprises selecting one of a plurality of possible calibration lines having various baselines and slopes based at least in part on prior information indicative of typical distribution of slopes and/or baselines.
10. The method of claim 1 , wherein the slope is determined, at least in part, based on in-vitro slope information determined by a benchtop calibration process.
11. The method of claim 1 , further comprising receiving reference data from a reference analyte monitor, wherein the slope is determined, at least in part, based on the reference analyte value.
12. The method of claim 1 , wherein the prior distribution information is derived from in vivo testing of at least one other transcutaneous analyte sensor or in vitro testing of at least one other transcutaneous analyte sensor.
13. The method of claim 1 , wherein displaying the generated estimated analyte value is performed in substantially real time.
14. The method of claim 1 , wherein the analyte is glucose.
15. The method of claim 1 , wherein the prior distribution information comprises normal distributions.
16. The method of claim 1 , wherein the slope of the conversion function is determined based at least in part on corrections for a difference between an in viva sensor sensitivity and an in vitro sensor sensitivity.
17. The method of claim 1 , wherein receiving the sensor data from the transcutaneous analyte sensor is performed before determining the conversion function.
18. The method of claim 1 , wherein determining the conversion function is performed before receiving the sensor data from the transcutaneous analyte sensor.
19. A system for calibrating a transcutaneous analyte sensor, comprising:
a transcutaneous analyte sensor configured to provide sensor data indicative of an analyte concentration in a host;
a processor module configured to determine a conversion function, wherein the conversion function comprises at least one of a slope or a baseline, wherein the slope is representative of a sensor sensitivity, wherein the at least one of the slope or the baseline is determined by selecting a most probable slope and/or baseline based at least in part on prior distribution information, wherein the prior distribution information is generated before insertion of the transcutaneous analyte sensor in the host, wherein the processor module is configured to convert the sensor data using the conversion function, and wherein the processor module is configured to generate an estimated analyte value based at least in part on the converted sensor data; and
a display configured to display the generated estimated analyte value.
20. The system of claim 19 , wherein the processor module is configured to determine the slope based at least in part on prior slope distribution information.
21. The system of claim 20 , wherein the processor module is configured to determine the slope by selecting a most probable slope from a distribution of slopes based at least in part on the prior slope distribution information.
22. The system of claim 19 , wherein the processor module is configured to determine the baseline based at least in part on prior baseline distribution information.
23. The system of claim 22 , wherein the processor module is configured to determine the baseline by selecting a most probable baseline from a distribution of baselines based at least in part on the prior baseline distribution information.
24. The system of claim 19 , wherein the processor module is configured to determine the slope and the baseline based at least in part on prior slope and baseline distribution information.
25. The system of claim 16 , wherein the prior distribution information comprises normal distributions.
26. The system of claim 19 , wherein the slope of the conversion function is determined based at least in part on corrections for a difference between an in viva sensor sensitivity and an in vitro sensor sensitivity.
27. The system of claim 19 , wherein the prior distribution information is derived from in viva testing of at least one other transcutaneous analyte sensor or in vitro testing of at least one other transcutaneous analyte sensor.
28. The system of claim 19 , wherein the analyte is glucose.