For the first episode of DVT, patients should be treated for 3-6 months. Recurrent episodes should be treated for at least 1 year...Laboratory analysis has also been used in aiding the diagnosis of venous thrombosis. Protein S, protein C, antithrombin III (ATIII), factor V Leiden, prothrombin 20210A mutation, antiphospholipid antibodies, and homocysteine levels can be measured. Deficiencies of these factors or the presence of these abnormalities all produce a hypercoagulable state. These are rare causes of deep venous thrombosis (DVT). Laboratory investigations for these abnormalities are primarily indicated when DVT is diagnosed in patients younger than 50 years, when there is a confirmed family history of a hypercoagulable state or a familial deficiency, when venous thrombosis is detected in unusual sites, and in the clinical setting of warfarin-induced skin necrosis.D dimer assy can be done... Consult nearest vascular surgeon they will help you further...