Anti-coagulation treatments are required for medical conditions that become more and more frequent with the ageing of the population in developed countries (atrial fibrillation, deep-venous thrombosis, heart prosthetic valves, etc.). These treatments generally use coumarin derivative (vitamin-K antagonist), whose activity needs to be monitored in order to keep the patient in an appropriate therapeutic range. This measurement can be done in laboratories but can also be performed by the patient himself using portable devices. This paper presents the different technological ways to selfmonitor vitamin-K antagonist treatment by measuring coagulation time. It will focus on portable devices, well suited to be used at home and on device to be manipulated by the patient, thus not requiring an extensive training nor sample treatment.