The present invention provides an anticoagulant agent including a first element capable of inhibiting coagulation and a second element capable of targeting an activated platelet wherein upon administration of element directs the first element to the activated platelet. Also provided is a probe for detecting a blood vessel abnormality including (a) a binding element capable of targeting an activated platelet and (b) a label. Applicant has shown that agents and probes directed to activated platelets are useful in the diagnosis and therapy of coagulation disorders.
