Method and assembly for determining the temperature of a test sensor

A device for determining an analyte concentration in a fluid sample, comprising:

• a receiving port that receives a test sensor, the test sensor including a fluid-receiving area for receiving a fluid sample, the fluid-receiving area containing a reagent that produces a measurable reaction with an analyte in the fluid sample, the test sensor having a test-sensor temperature and the reagent having a reagent temperature;
• a measurement system that measures the reaction between the reagent and the analyte;
• a temperature-measuring system that measures the test sensor temperature when the test sensor is received into the receiving port, a concentration of the analyte in the fluid sample being determined according to the measurement of the reaction and the measurement of the test sensor temperature;
• and
• a diagnostic system that determines an accuracy of the temperature-measuring system, the diagnostic system including a reference object that achieves at least one reference temperature, the temperature-measuring system measuring at least one test temperature for the reference object when the reference object achieves the at least one reference temperature, and the diagnostic system determining the accuracy of the temperature-measuring system by comparing the at least one test temperature to the corresponding reference temperature.