An electrochemical analysis system for analytical determination of a constituent of a sample includes a disposable analysis element and an evaluation unit. The disposable analysis element includes an isolating carrier with a sample application device for applying a sample thereto for analysis, and at least one sensor with a working electrode and a reference electrode for sensing electrical properties of the sample. The analysis element also includes a connection zone with connecting contacts which are connected to the electrodes via connecting leads. The evaluation unit includes an analysis element connector for electrically connecting to the connecting contacts of the analysis element, and a measuring and evaluation circuit for measuring electrical variation characteristics of the electrical properties sensed by the sensor on the analysis element. This circuit also converts a measured value into an analytical value, and includes a changeover device for changing over connection of an electrical power source with a current measuring device or a voltage measuring device to different connecting contacts of the analysis element.