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 (138, 140) 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;