Disclosed herein is a method for identifying patients with cryptogenic stroke or embolic stroke of undetermined source (ESUS) who are at risk for having occult atrial fibrillation, underlying malignancy, and/or recurrent arterial thromboembolic events. Also disclosed is a method for determining who among these patients will benefit from anticoagulants. Also disclosed herein is a method to predict whether the anticoagulant is sufficiently effective to reduce the activated coagulation system in a patient. Also disclosed wherein is a method for identifying patients with cardiovascular and cerebrovascular arterial diseases who have occult atrial fibrillation, underlying but unrecognized malignancy, and/or are at high risk of recurrent arterial thromboembolic events.
