Suspicion for hypercoagulable states as the cause of stroke varies by clinical scenario, but they may be considered in younger populations with no identifiable cause for stroke, self- or family history of unprovoked thrombosis, prior spontaneous abortion, or coexistence of systemic signs and symptoms sugges- tive of hypercoagulability. Recommendation-Specific Supportive Text 1. Thrombophilic states such as prothrombin 20210A mutation; activated protein C resistance (often caused by factor V Leiden); deficiencies of protein C, protein S, or antithrombin; and ele- vated factor VIII levels have been associated with higher stroke risk in selected populations without especially among people with The risk of stroke recurrence among stroke survivors with thrombophilic traits is less Furthermore, although individuals who carry 1 of these disease traits may be considered hypercoagulable, the ideal treatment (antiplatelet versus anticoagulation) remains unknown. Among patients with stroke and unprovoked deep vein thrombosis with or without a positive blood test for thrombophilic states, adhering to deep vein thrombosis treat- ment recommendations seems reasonable if they otherwise meet eligibility criteria.606 Therefore, in CLINICAL STATEMENTS AND GUIDELINES Kleindorfer the absence of a diagnosis that would change the default treatment for ischemic stroke, it is uncertain whether testing for these hematologic traits is of benefit in the context of secondary stroke prevention. If in certain clinical scenarios (eg, paradoxical emboli caused by venous throm- bosis or recurrent venous thrombosis) testing for thrombophilic states is considered, testing for protein C, protein S, or antithrombin levels should be deferred or repeated at least 4 to 6 weeks (or up to 6 months for factor VIII609 ) after the acute stroke given that these protein levels may be altered during the acute stroke phase.607,608,610,611 5.8.2. Antiphospholipid Syndrome Recommendations for Antiphospholipid Syndrome Referenced studies that support recommendations are summarized in online Data Supplement 46. 