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 system for calibrating a continuous analyte sensor, comprising:
a continuous analyte sensor configured to provide sensor data indicative of an analyte concentration in a host; and
a processor module configured to determine a conversion function, wherein the conversion function comprises a slope representative of a sensor sensitivity, wherein the slope is determined by selecting a most probable slope from a distribution of slopes, and wherein the processor module is configured to convert the sensor data using the conversion function.
2. The system of claim 1 , wherein the distribution of slopes comprises prior slope distribution information.
3. The system of claim 1 , wherein the conversion function further comprises a baseline, and wherein the processor module is configured to determine the baseline based on prior baseline distribution information.
4. The system of claim 3 , wherein the processor module is configured to determine the baseline by selecting a most probable baseline from a distribution of baselines based on the prior baseline distribution information.
5. The system of claim 1 , wherein the conversion function further comprises a baseline, and wherein the processor module is configured to determine the slope and the baseline based on prior slope and baseline distribution information.
6. The system of claim 1 , wherein the conversion function further comprises a baseline, and wherein the processor module is configured to determine the slope and the baseline by selecting a most probable slope and a most probable baseline from a distribution of slopes and baselines based on the prior slope and baseline distribution information.
7. The system of claim 6 , wherein the processor module is configured to select the most probable slope and the most probable baseline by selecting a slope and baseline closest to the maximum joint probability of both the slope and baseline distributions.
8. The system of claim 1 , wherein the conversion function further comprises a baseline, and wherein the processor module is configured to determine the conversion function by selecting one of a plurality of possible calibration lines having various baselines and slopes based on prior information indicative of typical distribution of slopes and/or baselines.
9. The system of claim 1 , wherein the slope is determined, at least in part, based on in-vitro slope information determined by a benchtop calibration process.
10. The system of claim 1 , wherein the processor module is configured to receive reference data from a reference analyte monitor, and wherein the slope is determined, at least in part, based on the reference analyte value.
11. The system of claim 1 , wherein the distribution of slopes is derived from in vivo testing of at least one other continuous glucose sensor or in vitro testing.
12. The system of claim 1 , wherein the processor module is configured to display the converted sensor data in substantially real time.
13. The system of claim 1 , wherein the analyte is glucose.