Abstract: Electrochemical system for measuring a value representing the coagulation time of a drop of whole blood including: an electrochemical sensor in the shape of a strip of small dimensions bearing at least a reference electrode and a working electrode on which a specific reagent is immobilized, including at least one chemical substrate one terminal link of which can be cut off by the thrombin enzyme to give charged groups (LG), and a measuring apparatus intended to receive said sensor allowing a given voltage or current to be imposed across the electrodes of the sensor, the electric signal resulting from the migration of the charged groups to be processed, said signal to be correlated with a value representing the coagulation time, and said value to be displayed on a display panel. The specific reagent preferably includes an oligopeptidic derivative as a substrate, a thromboplastin and a buffer medium.