Arrangement for testing a sample for at least one substance, wherein the arrangement comprises - a sensor unit, - a monitoring unit (40, 40.1, 70) having a first monitoring sensor (43, 78), and - an evaluation program that can be run on a computer, wherein the sensor unit comprises - an input unit and - a substance sensor, wherein the input unit - allows the input of a sample to be tested and - is capable of accepting a submitted sample, wherein the substance sensor comprises - at least one chemical reagent and - at least one indicator, wherein the or each reagent - is assigned to at least one substance and - is capable of chemically reacting with a sample taken up by the input unit, wherein the chemical reaction of the or each reagent depends upon the presence and/or concentration of the or each assigned substance in a sample taken up by the input unit, wherein the or each indicator is designed to visually display the corresponding result of a chemical reaction, wherein the sensor unit can be connected to the monitoring unit (40, 40.1, 70) in such a way that, after the connection has been established, the sensor unit is unable to perform any movement relative to the monitoring unit (40, 40.1, 70), and wherein the first monitoring sensor (43, 78) is designed to automatically measure a degree of a movement of the sensor unit connected to the monitoring unit (40, 40.1, 70) in space, and wherein the evaluation program is designed to automatically decide, by evaluating measured values of the first monitoring sensor (43, 78), whether the actual temporal course of the movement of the sensor unit in space is equal to a predetermined temporal target course up to a predetermined tolerance. - a sensor unit, - a monitoring unit (40, 40.1, 70) having a first monitoring sensor (43, 78), and - an evaluation program that can be run on a computer, wherein the sensor unit comprises - an input unit and - a substance sensor, wherein the input unit - allows the input of a sample to be tested and - is capable of accepting a submitted sample, wherein the substance sensor comprises - at least one chemical reagent and - at least one indicator, wherein the or each reagent - is assigned to at least one substance and - is capable of chemically reacting with a sample taken up by the input unit, wherein the chemical reaction of the or each reagent depends upon the presence and/or concentration of the or each assigned substance in a sample taken up by the input unit, wherein the or each indicator is designed to visually display the corresponding result of a chemical reaction, wherein the sensor unit can be connected to the monitoring unit (40, 40.1, 70) in such a way that, after the connection has been established, the sensor unit is unable to perform any movement relative to the monitoring unit (40, 40.1, 70), and wherein the first monitoring sensor (43, 78) is designed to automatically measure a degree of a movement of the sensor unit connected to the monitoring unit (40, 40.1, 70) in space, and wherein the evaluation program is designed to automatically decide, by evaluating measured values of the first monitoring sensor (43, 78), whether the actual temporal course of the movement of the sensor unit in space is equal to a predetermined temporal target course up to a predetermined tolerance.