Thrombophilia evaluations are usually performed to assess the need to extend anticoagulation, hence testing should be performed in a steady state, remote from the acute event. Laboratory assays to detect thrombophilic states include highly sensitive and specific test like molecular diagnosis, immunologic and functional assays. Many coagulation factors and inhibitors are affected during acute thrombosis, acute illnesses, inflammatory conditions, pregnancy certain medications. Antithrombin is decreased by heparin and acute thrombosis whereas protein C & S levels are increased during acute thrombosis, but decreased by warfarin. Antiphospholipid antibodies like lupus anticoagulants, anti cardiolipin antibodies & anti beta 2 glycprotein antibodies are also associated with thromboembolic disease states. Higher levels of factor VIII (>150%), factor V leiden mutations and increased homocysteine levels are also associated with increased risk of thromboembolic disease.