A kit for determining a concentration of at least one analyte in a body fluid of a user, the kit comprising: a) a sensor module comprising i. at least one sensor element adapted to determine the concentration of the analyte, wherein the sensor element is at least partly implantable into a body tissue of the user; ii. at least one control device connected to the sensor element , wherein the control device comprises at least one data collection device adapted to collect measurement data acquired by using the sensor element , wherein the control device further comprises at least one wireless near-field communication device adapted to transmit measurement data, wherein the sensor module comprises a sensor module mechanical interface ; b) at least one data reader module adapted to receive measurement data transmitted by the sensor module via wireless near-field communication, wherein the data reader module comprises at least one data storage device and is adapted to store the measurement data; c) at least one data transmission module adapted to receive measurement data transmitted by the sensor module via wireless near-field communication, wherein the data transmission module comprises at least one wireless far-field communication device , wherein the wireless far-field communication device is adapted to transmit at least part of the measurement data to an external device via wireless far-field communication; wherein the data reader module and the data transmission module each comprise a mechanical interface adapted to reversibly engage the sensor module mechanical interface , thereby alternatively generating a fixed spatial relationship between the sensor module and the data reader module or the sensor module and the data transmission module ; wherein the data reader module and the data transmission module are separate components. a) a sensor module comprising i. at least one sensor element adapted to determine the concentration of the analyte, wherein the sensor element is at least partly implantable into a body tissue of the user; ii. at least one control device connected to the sensor element , wherein the control device comprises at least one data collection device adapted to collect measurement data acquired by using the sensor element , wherein the control device further comprises at least one wireless near-field communication device adapted to transmit measurement data, wherein the sensor module comprises a sensor module mechanical interface ; i. at least one sensor element adapted to determine the concentration of the analyte, wherein the sensor element is at least partly implantable into a body tissue of the user; ii. at least one control device connected to the sensor element , wherein the control device comprises at least one data collection device adapted to collect measurement data acquired by using the sensor element , wherein the control device further comprises at least one wireless near-field communication device adapted to transmit measurement data, b) at least one data reader module adapted to receive measurement data transmitted by the sensor module via wireless near-field communication, wherein the data reader module comprises at least one data storage device and is adapted to store the measurement data; c) at least one data transmission module adapted to receive measurement data transmitted by the sensor module via wireless near-field communication, wherein the data transmission module comprises at least one wireless far-field communication device , wherein the wireless far-field communication device is adapted to transmit at least part of the measurement data to an external device via wireless far-field communication; <EOS>