Transcutaneous analyte sensor

A system for monitoring a glucose concentration in a host, the system comprising:

• a substantially continuous glucose sensor configured to produce sensor data indicative of a glucose concentration in a host;
• a sensor data receiving module configured to receive the sensor data from the substantially continuous glucose sensor;
• a reference data receiving module configured to receive reference data from an in vitro single point glucose monitor, the in vitro single point glucose monitor configured to receive a biological sample from the host and to measure a glucose concentration in the sample;
• a processor module in communication with the sensor data receiving module and the reference data receiving module;
• and
• computer readable memory comprising:
• instructions configured to cause the processor module to calibrate the sensor data received from the substantially continuous glucose sensor;
• instructions configured to cause the processor module to determine a rate of change of the calibrated sensor data;
• instructions configured to determine whether the rate of change is within a range of rates of change delimited by maximum normally sustainable rates of change of glucose in humans;
• and
• instructions configured to allow the processor module to calibrate the sensor data using the reference data when the rate of change is within the range of rates of change delimited by maximum normally sustainable rates of change of glucose in humans, but not allow the processor module to calibrate the sensor data using the reference data when the rate of change is outside the range of rates of change delimited by maximum normally sustainable rates of change of glucose in humans.