1. Prior history of DVT, VTE or PE. (deep venous thrombosus, venous thromboembolism, or pulmonary embolus)
2. Malignancy (active or in a patient’s history)
3. Thrombophilia disorders.*
4. Obesity (particularly for obese patients <40 years of age)
5. Use of oral contraceptives, tamoxifen, hormone replacement therapy or estrogen-containing drugs.
*Inherited and acquired Thrombophilia disorders include:
Factor V Leiden mutation
Prothrombin 20210A mutation (found only in whites)
Protein S deficiency
Protein C deficiency
High levels of: Fibrinogen, Plasminogen, Factor VIII, Factor IX, Thrombin activatable fibrinolysis inhibitor or Protein C inhibitor.
Low levels of tissue factor pathway inhibitor (TFPI)
Hyperhomocysteinemia (plasma homocysteine level >18.5 mmol/L)
Antiphospholipid antibodies (lupus anticoagulant & anti-cardiolipin)