We present a real-time coagulation-monitoring sensor by using an externally vibrated, self-sensing piezoresistive microcantilever for disposable point-of-care coagulation.Patients with cardiovascular disease to avoid the thrombosis formation are required to take anticoagulant drugs periodically.With the increasing use of oral anti-coagulant drugs and increasing adverse drug events, the need for personal self-diagnosis has become necessary.Prothrombin time (PT) is an index for anticoagulant therapy to determine the blood condition in coagulation reaction.