The formation of blood clots in the arteries and veins can increase the risk of heart attack and stroke. Individuals at high risk of blood clots are often treated with anticoagulants – drugs that thin the blood and prevent the clotting process. However, anticoagulant therapy requires patients to undergo frequent monitoring of blood flow in the hospital. Furthermore, if a person takes the wrong dosage of anticoagulants, this can cause cardiovascular problems rather than help reduce them. With this in mind, researchers in Switzerland have created a device that could allow patients undergoing anticoagulant therapy to self-monitor.