An analyte concentration sensor system for measuring an analyte of a fluid sample of a user, the sensor system comprising: a biosensor interface operable to be connected to a test sensor holding the fluid sample; a thermistor based temperature sensor configured to measure ambient temperature; a controller coupled to the biosensor interface and the temperature sensor, the controller being configured to: generate an input signal to the biosensor interface; read an output signal from the biosensor interface; determine a measured ambient temperature from the temperature sensor; execute a temperature estimation algorithm to determine an estimated ambient temperature; determine an absolute difference between the estimated ambient temperature and the measured ambient temperature; select one of the estimated ambient temperature or the measured ambient temperature, the selection based on the estimated ambient temperature, the measured ambient temperature, and the absolute difference between the estimated ambient temperature and the measured ambient temperature when the absolute difference is less than a largest allowed temperature compensation value; provide the selected estimated ambient temperature or measured ambient temperature as a temperature input to an analyte concentration determination algorithm; determine an analyte concentration from executing the analyte concentration determination algorithm; and report an error code for the test sensor if the absolute value of the difference between the estimated ambient temperature and the measured ambient temperature is greater than the largest allowed temperature compensation value. a biosensor interface operable to be connected to a test sensor holding the fluid sample; a thermistor based temperature sensor configured to measure ambient temperature; a controller coupled to the biosensor interface and the temperature sensor, the controller being configured to: generate an input signal to the biosensor interface; read an output signal from the biosensor interface; determine a measured ambient temperature from the temperature sensor; execute a temperature estimation algorithm to determine an estimated ambient temperature; determine an absolute difference between the estimated ambient temperature and the measured ambient temperature; select one of the estimated ambient temperature or the measured ambient temperature, the selection based on the estimated ambient temperature, the measured ambient temperature, and the absolute difference between the estimated ambient temperature and the measured ambient temperature when the absolute difference is less than a largest allowed temperature compensation value; provide the selected estimated ambient temperature or measured ambient temperature as a temperature input to an analyte concentration determination algorithm; determine an analyte concentration from executing the analyte concentration determination algorithm; and report an error code for the test sensor if the absolute value of the difference between the estimated ambient temperature and the measured ambient temperature is greater than the largest allowed temperature compensation value. generate an input signal to the biosensor interface; read an output signal from the biosensor interface; determine a measured ambient temperature from the temperature sensor; execute a temperature estimation algorithm to determine an estimated ambient temperature; determine an absolute difference between the estimated ambient temperature and the measured ambient temperature; select one of the estimated ambient temperature or the measured ambient temperature, the selection based on the estimated ambient temperature, the measured ambient temperature, and the absolute difference between the estimated ambient temperature and the measured ambient temperature when the absolute difference is less than a largest allowed temperature compensation value; provide the selected estimated ambient temperature or measured ambient temperature as a temperature input to an analyte concentration determination algorithm; determine an analyte concentration from executing the analyte concentration determination algorithm; and report an error code for the test sensor if the absolute value of the difference between the estimated ambient temperature and the measured ambient temperature is greater than the largest allowed temperature compensation value.