A structured approach to the diagnosis and management of unexplained arterial thrombosis.^2-5  *Includes factor V Leiden, prothrombin G20210A mutation, protein C deficiency, protein S deficiency, and antithrombin deficiency. aCL, anticardiolipin; aβ₂GPI, anti-β2 glycoprotein 1; CBC, complete blood count; CRP, C-reactive protein; DM, diabetes; ESR, erythrocyte sedimentation rate; HbA1c, hemoglobin A1c; HLD, hyperlipidemia; HTN, hypertension; LA, lupus anticoagulant; PCR, polymerase chain reaction; PNH, paroxysmal nocturnal hemoglobinuria; TEE, transesophageal echocardiogram; TTE, transthoracic echocardiogram; UA, urinalysis.